A microcrystalline glass, a chemically strengthened microcrystalline glass, a preparation method therefor and applications thereof

Abstract

The application discloses a microcrystalline glass, a chemically strengthened microcrystalline glass and a preparation method and application thereof. The application provides a microcrystalline glass with a specific crystal phase structure by optimizing a crystal phase structure, wherein the main crystal phase is soda nepheline, and the secondary crystal phase contains lithia nepheline. The chemically strengthened microcrystalline glass with good impact resistance and extrusion resistance, large fragment size after breaking and high safety can be prepared from the microcrystalline glass, and is suitable for fields such as electronic device cover glass. Meanwhile, the lithium content of the microcrystalline glass is low, which is beneficial to reducing lithium resource consumption and manufacturing cost.

Description

Technical Field

[0001] This application relates to the field of glass-ceramic technology, specifically to a glass-ceramic, a chemically strengthened glass-ceramic, its preparation method, and its application. Background Technology

[0002] As electronic devices (such as mobile phones, watches, and tablets) continue to evolve towards ultra-thin designs, the market demand for thinner and lighter protective cover glass is increasing. To balance thinness with high-strength properties such as impact resistance, pressure resistance, scratch resistance, and abrasion resistance, cover glass typically undergoes chemical strengthening treatment to form reinforced glass with a certain stress level. Currently, the microcrystalline glass used for cover glass on the market is mainly a lithium aluminum silicon system with a high lithium content. However, the rapid development of the new energy industry in recent years has driven a continuous rise in lithium raw material prices, leading to a significant increase in production costs. Affected by the increasingly scarce and expensive lithium resources, the development of low-cost transparent microcrystalline glass that uses less or no lithium has become increasingly urgent. Therefore, in recent years, lithium sodium aluminum silicon system microcrystalline glass with relatively low lithium content has become one of the research hotspots in the industry. Summary of the Invention

[0003] Nepheline-based glass-ceramics, due to their ability to utilize relatively low lithium content, represent a significant development direction for low-cost transparent glass-ceramics. However, this application, in its research on nepheline-based glass-ceramics, discovered that:

[0004] (1) In glass-ceramics with sodium nepheline as the main crystal phase: if the lithium content is too low, problems such as insufficient deep stress after chemical strengthening, shallow compressive stress layer, and poor drop resistance are likely to occur; if lithium is mainly present in the glass phase and does not form lithium nepheline crystal phase, problems such as low tensile stress, long strengthening time, and poor drop resistance are likely to occur; if the overall crystallinity is high and the lithium nepheline crystal phase content is high, its crystal structure is likely to change during the chemical strengthening process, resulting in poor drop resistance.

[0005] (2) In glass-ceramics with nepheline as the main crystal phase: Although the depth of deep stress and compressive stress layer is improved after chemical strengthening, when the crystallinity of glass-ceramics is high, its crystal structure is prone to change during the chemical strengthening process, resulting in poor drop resistance.

[0006] In addition, some chemically strengthened glass-ceramics made from nepheline glass-ceramics are prone to producing a large number of small fragments after breakage, posing a safety hazard.

[0007] To address the aforementioned issues, this application provides a high-strength, transparent glass-ceramic with sodium nepheline as the main crystalline phase and lithium nepheline as the secondary crystalline phase, through optimization of the glass composition and crystal phase structure. This glass-ceramic possesses high crystallinity and a specific crystal phase structure, which not only enhances its inherent strength but also strengthens its crystal structure stability. After chemical strengthening, this glass-ceramic achieves high mechanical strength and excellent breakage safety. Specifically, this chemically strengthened glass-ceramic exhibits both good impact and compression resistance, is not prone to spontaneous breakage, and produces relatively large fragments after breakage, effectively avoiding safety hazards posed by small fragments. It also meets temporary emergency use needs after breakage. Using this chemically strengthened glass-ceramic reduces raw material costs while improving the user experience of the final product.

[0008] To achieve the above objectives, the technical solution provided in this application includes:

[0009] (1) This application provides a glass-ceramic, which includes a primary crystalline phase of nepheline and a secondary crystalline phase of nepheline. The mass percentage of nepheline in all crystalline phases is not less than 80%, and the mass percentage of nepheline accounts for 3.5% to 15% of the sum of the masses of nepheline and nepheline. The crystallinity of the glass-ceramic is >60 wt%.

[0010] The composition of the glass-ceramic, by mass percentage of oxides, includes: SiO2: 47-52%, Al2O3: 23-28%, P2O5: 3.5-4.5%, ZrO2: 1.5-4%, Na2O: 10-13%, K2O: 0-2%, Li2O: 3-5.5%, CaO: 0-2%, ZnO: 0-3%, B2O3: 0-3%, and Y2O3: 0-1.5%. Without being limited by any theory, this application discovers that by making a glass-ceramic with high crystallinity satisfy a specific crystal phase structure, a nepheline glass-ceramic possessing both high strength and good crystal structure stability can be obtained. After chemical strengthening, this glass-ceramic can yield a chemically strengthened glass-ceramic with high mechanical strength and good breakage safety. Furthermore, without being limited by any theory, this application discovers that the synergistic effect of key components in specific amounts can achieve unexpected technical results. For example, controlling the content of SiO2, Al2O3, Na2O, and Li2O within a specific range is beneficial for ensuring the formation of a specific nepheline crystal phase structure and avoiding melting difficulties. Simultaneously, controlling the Li2O content while managing costs ensures that the highly crystalline glass-ceramic forms a specific stress structure after chemical strengthening, guaranteeing high strength, and also prevents excessive precipitation of the lithium nepheline crystal phase, thus avoiding phase transformation during chemical strengthening. Furthermore, the synergistic effect of ZrO2 and P2O5 not only helps refine grains and promote uniform crystallization but also improves the fracture toughness of the glass-ceramic.

[0011] (2) This application also provides a microcrystalline glass, which includes a primary crystalline phase of sodium nepheline and a secondary crystalline phase of nepheline, wherein 0 < nepheline content ≤ 10wt%, sodium nepheline content ≥ 55wt%, the mass of nepheline accounts for 3.5% to 15% of the sum of the masses of nepheline and sodium nepheline, and the crystallinity of the microcrystalline glass is > 60wt%.

[0012] Unrestricted by any particular theory, this application discovers that by enabling microcrystalline glass with high crystallinity to satisfy a specific crystal phase structure, nepheline microcrystalline glass possessing both high strength and good crystal structure stability can be obtained. After chemical strengthening, this microcrystalline glass yields chemically strengthened microcrystalline glass with high mechanical strength and good breakage safety. Specifically, this chemically strengthened microcrystalline glass exhibits good impact and compression resistance, is not prone to spontaneous breakage, and produces relatively large fragments after breakage, effectively avoiding the safety hazards posed by small fragments. It also meets the needs for temporary emergency use after breakage.

[0013] (3) In some embodiments of this application, the microcrystalline glass described in (1) or (2) satisfies the following: the composition of the microcrystalline glass described in (1) or (2) is satisfied based on the mass percentage of oxides:

[0014] 2.2≤Na2O / Li2O≤3, preferably 2.3≤Na2O / Li2O≤2.8;

[0015] 4.5≤Na2O / (P2O5×0.5)≤7.5, preferably 4.5≤Na2O / (P2O5×0.5)≤6.5;

[0016] 1.7≤Na2O / (Li2O+K2O)≤3, preferably 1.8≤Na2O / (Li2O+K2O)≤2.7.

[0017] (4) In some embodiments of this application, the microcrystalline glass described in (2) satisfies the following: the composition of the microcrystalline glass, based on the mass percentage of oxides, includes:

[0018] SiO2: 47~52%, Al2O3: 23~28%, P2O5: 3.5~4.5%, ZrO2: 1.5~4%, Na2O: 10~13% , K2O: 0~2%, Li2O: 3~5.5%, CaO: 0~2%, ZnO: 0~3%, B2O3: 0~3%, Y2O3: 0~1.5%.

[0019] (5) In some embodiments of this application, the glass-ceramic of any one of (1)-(4) satisfies the following: in the glass-ceramic, the mass of nepheline accounts for 3.5% to 10% of the sum of the masses of nepheline and sodium nepheline, preferably 3.5% to 7.5%, and more preferably 3.5% to 5%; and / or, in the glass-ceramic, the mass percentage of sodium nepheline in all crystal phases is not less than 90%.

[0020] (6) In some embodiments of this application, (1) the microcrystalline glass satisfies the following: in the microcrystalline glass: 0 < nepheline content ≤ 10 wt%, sodium nepheline content ≥ 55 wt%.

[0021] (7) In some embodiments of this application, in any one of (1)-(6) the microcrystalline glass: 0 < nepheline content ≤ 8wt%, 60wt% ≤ sodium nepheline content ≤ 80wt%; preferably, 3wt% ≤ nepheline content ≤ 6wt%, 63wt% ≤ sodium nepheline content ≤ 75wt%.

[0022] (8) In some embodiments of this application, the glass-ceramic of any one of (1)-(7) satisfies the following: the crystallinity of the glass-ceramic is 65wt%~80wt%, preferably 68wt%~78wt%; and / or,

[0023] In the microcrystalline glass, the average grain size does not exceed 50 nm, preferably the average grain size is 10 nm to 40 nm, and more preferably the average grain size is 20 nm to 30 nm.

[0024] (9) In some embodiments of this application, the glass-ceramic of any one of (1)-(8) satisfies the following: the glass-ceramic contains, by mass percentage of oxides: 48-51% SiO2; and / or 23.5-27.5% Al2O3; and / or 3.7-4.3% P2O5; and / or 1.5-3.8% ZrO2; and / or 10-12.8% Na2O; and / or 0-1.5% K2O; and / or 3.5-5.2% Li2O; and / or 0-1.5% CaO; and / or 0-0.5% ZnO; and / or 0-2.1% B2O3; and / or 0-0.5% Y2O3.

[0025] (10) In some embodiments of this application, the glass-ceramic of any one of (1)-(9) satisfies:

[0026] When the thickness of the microcrystalline glass is 0.35mm~0.6mm, the haze of the microcrystalline glass is <0.2%, the b-value of the microcrystalline glass is <0.9, preferably b-value <0.8, more preferably b-value ≤0.75; and / or,

[0027] The microcrystalline glass is transparent in the visible light wavelength range; preferably, when the thickness of the microcrystalline glass is 0.35~0.6mm, the transmittance of the microcrystalline glass at a wavelength of 550nm is ≥85%, more preferably ≥90%, and even more preferably ≥90.5%.

[0028] (11) In some embodiments of this application, the glass-ceramic of any one of (1)-(10) satisfies the following: the Young's modulus of the glass-ceramic is ≥90 GPa, preferably 90 GPa~105 GPa; and / or,

[0029] The refractive index of the microcrystalline glass is 1.53~1.55; and / or,

[0030] The density of the microcrystalline glass is 2.5~2.7 g / cm³. 3 .

[0031] (12) This application provides a chemically strengthened glass-ceramic, the chemically strengthened glass-ceramic comprising a tensile stress layer and a compressive stress layer, the chemically strengthened glass-ceramic comprising a primary crystalline phase of nepheline and a secondary crystalline phase of nepheline, wherein the mass percentage of nepheline in all crystalline phases is not less than 80%, and the mass percentage of nepheline accounts for 3.5% to 15% of the sum of the masses of nepheline and nepheline, and the crystallinity of the chemically strengthened glass-ceramic is >60 wt%;

[0032] The composition of the chemically strengthened glass-ceramic tensile stress layer or the composition at the center of the chemically strengthened glass-ceramic, based on the mass percentage of oxides, includes:

[0033] SiO2: 47~52%, Al2O3: 23~28%, P2O5: 3.5~4.5%, ZrO2: 1.5~4%, Na2O: 10~13% , K2O: 0~2%, Li2O: 3~5.5%, CaO: 0~2%, ZnO: 0~3%, B2O3: 0~3%, Y2O3: 0~1.5%.

[0034] (13) This application also provides a chemically strengthened glass-ceramic, the chemically strengthened glass-ceramic comprising a tensile stress layer and a compressive stress layer, the chemically strengthened glass-ceramic comprising a primary crystalline phase of nepheline and a secondary crystalline phase of nepheline, wherein 0 < nepheline content ≤ 10 wt%, nepheline content ≥ 55 wt%, the mass of nepheline accounts for 3.5% to 15% of the sum of the masses of nepheline and nepheline, and the crystallinity of the chemically strengthened glass-ceramic is > 60 wt%.

[0035] The chemically strengthened glass-ceramic of this application is made from glass-ceramics that satisfy a specific crystal phase structure. Unrestricted by any theory, this application has discovered that because this glass-ceramic possesses both high strength and good crystal structure stability, it does not undergo significant phase transformation after chemical strengthening treatment, and its crystal phase structure remains basically stable. This results in chemically strengthened glass-ceramics with high mechanical strength and good breakage safety. Simultaneously, this chemically strengthened glass-ceramic also exhibits good impact and compression resistance, is not prone to spontaneous breakage, and produces relatively large fragments after breakage, effectively avoiding the safety hazards posed by small fragments. Furthermore, it can meet the needs of temporary emergency use after breakage.

[0036] (14) In some embodiments of this application, the chemically strengthened glass crystal described in (12) or (13) satisfies the following: the composition of the tensile stress layer of the chemically strengthened glass crystal or the composition at the center of the chemically strengthened glass crystal, based on the mass percentage of oxides, satisfies the following:

[0037] 2.2≤Na2O / Li2O≤3, preferably 2.3≤Na2O / Li2O≤2.8;

[0038] 4.5≤Na2O / (P2O5×0.5)≤7.5, preferably 4.5≤Na2O / (P2O5×0.5)≤6.5;

[0039] 1.7≤Na2O / (Li2O+K2O)≤3, preferably 1.8≤Na2O / (Li2O+K2O)≤2.7.

[0040] (15) In some embodiments of this application, (13) the chemically strengthened glass crystal satisfies the following: the composition of the tensile stress layer of the chemically strengthened glass crystal or the composition at the center of the chemically strengthened glass crystal, based on the mass percentage of oxides, includes:

[0041] SiO2: 47~52%, Al2O3: 23~28%, P2O5: 3.5~4.5%, ZrO2: 1.5~4%, Na2O: 10~13% , K2O: 0~2%, Li2O: 3~5.5%, CaO: 0~2%, ZnO: 0~3%, B2O3: 0~3%, Y2O3: 0~1.5%.

[0042] (16) In some embodiments of this application, the chemically strengthened glass crystal of any one of (12)-(15) satisfies the following: in the chemically strengthened glass crystal, the mass of nepheline accounts for 3.5% to 7.3% of the sum of the masses of nepheline and sodium nepheline, preferably 4% to 7%; and / or, in the chemically strengthened glass crystal, the mass percentage of sodium nepheline in all crystal phases is not less than 90%.

[0043] (17) In some embodiments of this application, (12) the chemically strengthened glass crystal satisfies the following: in the chemically strengthened glass crystal: 0 < nepheline content ≤ 10 wt%, sodium nepheline content ≥ 55 wt%.

[0044] (18) In some embodiments of this application, the chemically strengthened glass crystal in any one of (12)-(17) satisfies the following: the crystallinity of the chemically strengthened glass crystal is 65wt%~80wt%, preferably 67wt%~78wt%; and / or,

[0045] In the chemically strengthened glass-ceramic, the average grain size does not exceed 50 nm, preferably 10 nm to 40 nm, and more preferably 20 nm to 30 nm; and / or,

[0046] In the chemically strengthened glass-ceramic: 0 < nepheline content ≤ 8 wt%, 60 wt% ≤ sodium nepheline content ≤ 80 wt%, preferably, 3 wt% ≤ nepheline content ≤ 6 wt%, 63 wt% ≤ sodium nepheline content ≤ 75 wt%; and / or,

[0047] The chemically strengthened microcrystalline glass does not contain potassium nepheline in its crystal phase.

[0048] (19) In some embodiments of this application, the chemically strengthened glass-ceramic of any one of (12)-(18) satisfies the following: in the composition of the tensile stress layer of the chemically strengthened glass-ceramic or in the composition at the center of the chemically strengthened glass-ceramic, based on the mass percentage of oxides: the content of SiO2 is 48-51%; and / or, the content of Al2O3 is 23.5-27.5%; and / or, the content of P2O5 is 3.7-4.3%; and / or, the content of ZrO2 is 1.5-3.8%; and / or, the content of Na2O is 10-12.8%; and / or, the content of K2O is 0-1.5%; and / or, the content of Li2O is 3.5-5.2%; and / or, the content of CaO is 0-1.5%; and / or, the content of ZnO is 0-0.5%; and / or, the content of B2O3 is 0-2.1%; and / or, the content of Y2O3 is 0-0.5%.

[0049] (20) In some embodiments of this application, the chemically strengthened glass crystal of any one of (12)-(19) satisfies: the chemically strengthened glass crystal satisfies:

[0050] 0.20≤DOL_0 / t≤ 0.25, where DOL_0 is the compressive stress layer depth and t is the thickness of the chemically strengthened glass-ceramic; and / or, surface CS≥1400MPa, preferably surface CS is 1500MPa~1900MPa.

[0051] (21) The thickness of the microcrystalline glass or the chemically strengthened microcrystalline glass is not limited in this application, and those skilled in the art can choose according to their needs. For example, in some embodiments of this application, the chemically strengthened microcrystalline glass in any one of (12)-(20) satisfies the following: the thickness t of the chemically strengthened microcrystalline glass is 0.35mm~1.0mm, preferably 0.4mm~0.7mm, and more preferably 0.45mm~0.55mm.

[0052] (22) In some embodiments of this application, the chemically strengthened glass-ceramic of any one of (12)-(20) satisfies the following: when the thickness of the chemically strengthened glass-ceramic is (0.5±0.01) mm, the chemically strengthened glass-ceramic satisfies the following:

[0053] The tensile stress linear density CT_LD ≥ 35000 MPa / mm, preferably CT_LD is 35000 MPa / mm ~ 50000 MPa / mm; and / or,

[0054] CS_50 ≥ 100 MPa, preferably CS_50 is 100 MPa ~ 150 MPa, CS_50 refers to the compressive stress value at a depth of 50 μm from the main surface of the chemically strengthened glass-ceramic, in MPa; and / or,

[0055] |CT_AV|≥75MPa, preferably |CT_AV| is 75 MPa ~100MPa, where |CT_AV| is the absolute value of the average tensile stress in MPa; and / or,

[0056] DOL_K ≥ 6 μm, preferably 6 μm ~ 15 μm, where DOL_K refers to the depth of potassium ions that have penetrated into the glass through ion exchange, measured from the main surface of the chemically strengthened glass-ceramic; and / or,

[0057] The compressive stress layer depth DOL_0 > 95 μm, preferably DOL_0 is 100 μm to 120 μm.

[0058] (23) In some embodiments of this application, the chemically strengthened glass-ceramic of any one of (12)-(21) satisfies the following: when the chemically strengthened glass-ceramic is subjected to a sandpaper drop test, the sandpaper used is 120-grit sandpaper, and the thickness is not more than 0.60 mm, preferably 0.49 mm to 0.55 mm, more preferably 0.49 mm to 0.51 mm, the average sandpaper drop height of the chemically strengthened glass-ceramic is ≥0.9 m, and when the chemically strengthened glass-ceramic breaks after a drop, the average size of the longest side of the fragments is ≥15 mm; and / or,

[0059] The chemically strengthened glass-ceramic is pressed using a 10mm diameter round-headed metal pressure bar. The static compressive strength of the single bar that the chemically strengthened glass-ceramic can withstand is tested. When the thickness does not exceed 0.60mm, preferably 0.49mm~0.55mm, and more preferably 0.49mm~0.51mm, the static compressive strength of the single bar that the chemically strengthened glass-ceramic can withstand is ≥350N, preferably 350~500N; and / or,

[0060] A 32g steel ball is used to conduct a drop ball impact test on the chemically strengthened microcrystalline glass. When the thickness does not exceed 0.60mm, preferably when the thickness is 0.49mm~0.55mm, and more preferably when the thickness is 0.49mm~0.51mm, the drop ball impact height when the chemically strengthened microcrystalline glass breaks is ≥1.0m, preferably 1.0~1.5m.

[0061] (24) This application provides an electronic device comprising a glass crystal as described in any one of (1)-(11), or a chemically strengthened glass crystal as described in any one of (12)-(23). Exemplarily:

[0062] In some embodiments, the electronic device includes a housing assembled on the outside of the electronic device, the housing comprising a microcrystalline glass as described in any one of (1)-(11), or a chemically strengthened microcrystalline glass as described in any one of (12)-(23). The housing may be partially or entirely composed of microcrystalline glass or chemically strengthened microcrystalline glass. In some embodiments, the housing includes a display cover assembled on the front side of the electronic device, the display cover comprising a microcrystalline glass as described in any one of (1)-(11), or a chemically strengthened microcrystalline glass as described in any one of (12)-(23). In some embodiments, the housing includes a rear cover assembled on the rear side of the electronic device, the rear cover comprising a microcrystalline glass as described in any one of (1)-(11), or a chemically strengthened microcrystalline glass as described in any one of (12)-(23).

[0063] In some embodiments, the electronic device further includes a camera assembly, and the camera assembly is covered with a camera protective cover, the camera protective cover comprising microcrystalline glass as described in any one of (1)-(11), or chemically strengthened microcrystalline glass as described in any one of (12)-(23).

[0064] In some embodiments, the electronic device further includes a mid-frame located between the display module and the housing, the mid-frame comprising microcrystalline glass as described in any one of (1)-(11), or chemically strengthened microcrystalline glass as described in any one of (12)-(23).

[0065] In some embodiments, the electronic device in this application may be one or more of the following: display cover, back cover, camera protective cover, and middle frame, including any one of the microcrystalline glass as described in (1)-(11), or including any one of the chemically strengthened microcrystalline glass as described in (12)-(23).

[0066] (25) This application provides a cover glass comprising microcrystalline glass as described in any one of (1)-(11), or chemically strengthened microcrystalline glass as described in any one of (12)-(23). Exemplarily, the cover glass in this application can be used as a display screen cover, an electronic device back cover, or a camera protective cover.

[0067] (26) This application provides a glass article comprising microcrystalline glass as described in any one of (1)-(11), or chemically strengthened microcrystalline glass as described in any one of (12)-(23).

[0068] (27) This application provides a method for preparing microcrystalline glass. Each raw material component is prepared according to the proportion of the aforementioned oxides, melted, cooled and annealed to obtain a base glass. The base glass is then subjected to heat treatment, for example, nucleation treatment and crystallization treatment in sequence, to obtain microcrystalline glass.

[0069] In some embodiments of this application, the temperature is preferably increased to the nucleation temperature at a heating rate of 3°C / min to 15°C / min, the nucleation temperature is preferably 640°C to 660°C, and the nucleation time is preferably 10 min to 1440 min.

[0070] In some embodiments of this application, the temperature is preferably increased to the crystallization temperature at a heating rate of 3°C / min to 15°C / min, the crystallization temperature is preferably 725°C to 750°C, and the crystallization time is preferably 5 min to 1440 min.

[0071] Compared with the prior art, this application has the following beneficial effects:

[0072] This application addresses the technical problems of insufficient deep stress, shallow compressive stress layer, or long strengthening time, resulting in poor drop resistance in microcrystalline glass with a single sodium nepheline crystal phase and a specific crystal structure of nepheline as the main crystalline phase and lithium-containing nepheline as the secondary crystalline phase, through specific crystal structure control. It also solves the technical problem of poor mechanical properties caused by phase transformation during chemical strengthening of microcrystalline glass containing a relatively large amount of lithium nepheline crystal phase and high crystallinity. Furthermore, while optimizing mechanical properties, this application also achieves good breakage safety in chemically strengthened microcrystalline glass. The chemically strengthened microcrystalline glass prepared by this application has both good impact resistance and compression resistance, is not prone to spontaneous breakage, and produces relatively large fragments after breakage, thus avoiding the safety hazards caused by small fragments and meeting the needs for temporary emergency use after breakage.

[0073] This application achieves synergistic optimization of crystal phase structure stability, mechanical strength, and safety by precisely controlling the crystal phase ratio and component content of microcrystalline glass with high crystallinity, ensuring that chemically strengthened microcrystalline glass can be produced with both high mechanical strength and good safety.

[0074] This application significantly reduces the consumption of scarce lithium resources by reasonably controlling the amount of lithium source added, compared with traditional lithium aluminum silicon microcrystalline glass. It achieves high performance while ensuring controllable production costs, and has good prospects for industrial mass production and market application. Attached Figure Description

[0075] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0076] Figure 1 The image shows the DSC curve of the base glass in Example 9.

[0077] Figure 2 The image shows the XRD pattern of the microcrystalline glass of Example 9.

[0078] Figure 3 This is a comparison of the XRD curves of the microcrystalline glass and the chemically strengthened microcrystalline glass of Example 9.

[0079] Figure 4 The image shows the XRD pattern of the glass-ceramic in Comparative Example 1.

[0080] Figure 5The image shows a comparison of the XRD curves of the microcrystalline glass and the chemically strengthened microcrystalline glass in Comparative Example 1.

[0081] Figure 6 The image shows the XRD pattern of the glass-ceramic in Comparative Example 2.

[0082] Figure 7 The image shows a comparison of the XRD curves of the microcrystalline glass and the chemically strengthened microcrystalline glass in Comparative Example 2.

[0083] Figure 8 The transmittance curve of the microcrystalline glass in Example 9 is shown.

[0084] Figure 9 The graph shows the transmittance curves of the microcrystalline glass and the chemically strengthened microcrystalline glass of Example 9.

[0085] Figure 10 This is a schematic diagram of the fragments of the chemically strengthened microcrystalline glass of Example 9, Comparative Example 1, and Comparative Example 8 after a drop test.

[0086] Figure 11 This is a schematic diagram of the structure of chemically strengthened glass-ceramics, where t is the thickness, d is the depth of the compressive stress layer, 21 is the compressive stress layer, and 22 is the tensile stress layer. Detailed Implementation

[0087] The technical solutions of this application will be clearly and completely described below with reference to the embodiments and accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on this application are within the scope of protection of this application. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments used are not specified, they can be obtained commercially.

[0088] Unless otherwise specified in the specific circumstances, the numerical ranges listed herein include upper and lower limits, as well as all integers and fractions within those ranges, and are not limited to the specific values ​​listed when defining the range. For numerical ranges, endpoint values ​​of various ranges, endpoint values ​​of various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. The term "and / or" used herein is inclusive; for example, "A and / or B" means only A, or only B, or both A and B. Terms such as "about," "substantially the same," and similar expressions herein indicate that reasonable deviations are permissible.

[0089] It should be noted that the performance requirements (such as optical properties, Young's modulus, etc.) of the microcrystalline glass provided in this application are not limited to specific thicknesses or sizes. In specific embodiments, samples are prepared according to different testing standards to test properties such as Young's modulus and density. In this application, the optical properties are tested on samples with a thickness of approximately 0.50 mm, and the stress characteristics, drop resistance, compression resistance, drop ball resistance, and fragmentation are tested after strengthening the sample of this thickness. This is only a simplified explanation and is not intended to limit the scope of protection of this application.

[0090] In this application, glass-ceramic is a solid material comprising a glass phase and a crystalline phase (or also called a microcrystalline phase or crystalline phase).

[0091] In this application, chemically strengthened glass-ceramics are solid composite materials obtained by chemically strengthening glass-ceramics.

[0092] It should be understood that during chemical strengthening, after the glass-ceramic is placed in a molten salt bath for ion exchange, a compressive stress layer (or compressive stress region) forms on the surface of the glass-ceramic, while a tensile stress layer (or tensile stress region, tensile stress region) forms inside the glass-ceramic. That is, after chemical strengthening, a chemically strengthened glass-ceramic containing both a compressive stress layer and a tensile stress layer is obtained. The composition of the regions in the chemically strengthened glass-ceramic that have not undergone ion exchange, such as the tensile stress layer or the composition at the center, is the same as or substantially the same as that of the original glass-ceramic.

[0093] In this application, surface CS refers to the surface compressive stress (or surface compressive stress) of chemically strengthened glass-ceramics, which can be measured using an FSM-9000.

[0094] In this application, the compressive stress layer depth DOL_0 refers to the distance from any main surface of the chemically strengthened glass-ceramic to a position close to that main surface where the compressive stress is zero, which can be obtained by testing with an SLP-2000 stress meter.

[0095] In this application, DOL_K refers to the depth of potassium ions that have entered the glass interior through ion exchange, measured from the main surface of the chemically strengthened glass-ceramic, and can be determined using an FSM-9000.

[0096] In this application, CS_50 refers to the compressive stress value at a depth of 50 μm from the main surface of the chemically strengthened glass-ceramic, in MPa, which can be obtained by testing with an SLP-2000 stress meter (or also known as a scattered light photoelastic stress meter).

[0097] In this application, |CT_AV| refers to the absolute value of the average tensile stress, in MPa, which can be obtained by testing with an SLP-2000 stress meter.

[0098] In this application, CT_LD refers to the tensile stress linear density, with units of MPa / mm. CT_LD is calculated using the following formula in this application:

[0099]

[0100] Where t represents the thickness of the chemically strengthened glass-ceramic, in mm; DOL_0 represents the compressive stress layer depth of the chemically strengthened glass-ceramic, in μm; and |CT_AV| represents the absolute value of the average tensile stress of the chemically strengthened glass-ceramic, in MPa. It should be understood that the calculation formula for the tensile stress linear density involves substituting the data according to the above unit requirements to obtain the calculation result; the units are not involved in the calculation. In this application, the tensile stress linear density value is approximately the ratio of the definite integral of the tensile stress curve to the thickness of the chemically strengthened glass-ceramic.

[0101] In this application, the primary crystalline phase (or major crystalline phase) refers to a crystalline phase having a higher mass percentage (or weight percentage) than other crystalline phases present in the glass-ceramic or chemically strengthened glass-ceramic. The secondary crystalline phase (or minor crystalline phase) refers to crystalline phases present in the glass-ceramic or chemically strengthened glass-ceramic other than the primary crystalline phase, and its content is typically lower than that of the primary crystalline phase.

[0102] In this application, the composition at the center of the chemically strengthened glass-ceramic refers to the composition at or near the center of the depth or thickness of the chemically strengthened glass-ceramic. Since no ion exchange occurs at the center of the chemically strengthened glass-ceramic, it has the same composition and phase structure as the glass-ceramic itself.

[0103] In this application, the main surface refers to the surface with the largest surface area, such as the upper or lower surface of a horizontally placed microcrystalline glass sheet.

[0104] In this application, crystallinity refers to the percentage of the total mass of crystalline phases or crystals in a glass-ceramic (or chemically strengthened glass-ceramic) to the total mass of the glass-ceramic (or chemically strengthened glass-ceramic), or it is also referred to as the total content of crystalline phases in the glass-ceramic (or chemically strengthened glass-ceramic).

[0105] In this application, the optical b-value is used to characterize the yellow-blue value of a material. The optical b-value in this application is the transmitted light b-value; a positive optical b-value indicates that the material has a bluish tint.

[0106] Tensile stress layer (or tensile stress layer): refers to the region within chemically strengthened glass-ceramics where significant ion exchange has not occurred and the original composition and phase structure of the glass-ceramics are still maintained. This region is located between compressive stress layers symmetrically distributed on two opposing main surfaces, serving to balance the surface compressive stress.

[0107] I. Microcrystalline Glass

[0108] Unrestricted by any theory, this application, in its research on nepheline microcrystalline glass, discovered that different nepheline species of microcrystalline glass exhibit varying degrees of performance improvement after chemical strengthening treatment, for example:

[0109] Although nepheline glass-ceramics containing only sodium nepheline or lithium nepheline but with a low lithium nepheline content have relatively stable crystal structures and are not prone to phase transitions during chemical strengthening, they require a long chemical strengthening time or suffer from insufficient deep stress and shallow compressive stress layer depth after chemical strengthening. This results in poor drop resistance of the chemically strengthened glass-ceramics.

[0110] While nepheline microcrystalline glass containing only nepheline or both sodium nepheline and nepheline with a higher proportion of nepheline crystal phase may have improved depth of deep stress and compressive stress layer after chemical strengthening, its crystal structure is prone to change during the chemical strengthening process when the crystallinity of the microcrystalline glass is high. This can also lead to deviations in the drop resistance of the chemically strengthened microcrystalline glass.

[0111] Furthermore, after in-depth research on chemically strengthened glass-ceramics made from nepheline glass-ceramics, it was found that some nepheline-based chemically strengthened glass-ceramics are prone to producing a large number of small fragments after breakage, posing a safety hazard.

[0112] Based on this, this application provides a high-strength transparent glass-ceramic with sodium nepheline as the main crystalline phase and lithium-containing nepheline as the secondary crystalline phase by optimizing the glass composition and crystal phase structure. After chemical strengthening, this glass-ceramic achieves high mechanical strength and good safety. It exhibits good impact and compression resistance, is not prone to spontaneous breakage, and produces relatively large fragments upon breakage, avoiding the generation of numerous small fragments (not only avoiding safety hazards from small fragments but also meeting temporary emergency use needs after breakage). By optimizing the composition and controlling the proportion of crystalline phases, this application not only improves the crystallinity of the glass-ceramic, enhancing its inherent strength, but also strengthens the stability of the crystal structure, improving the mechanical strength and breakage safety of the chemically strengthened glass-ceramic, and enhancing the user experience of the end product.

[0113] In some embodiments of this application, a glass-ceramic is provided, wherein the crystallinity of the glass-ceramic is >60 wt%, and the glass-ceramic comprises a primary crystalline phase of sodium nepheline and a secondary crystalline phase of lepidolite, wherein the mass of lepidolite accounts for 3.5% to 15% of the sum of the masses of lepidolite and sodium nepheline, preferably 3.5% to 10%, more preferably 3.5% to 7.5%, and even more preferably 3.5% to 5%. Without being limited by any theory, this application has discovered that by making a glass-ceramic with high crystallinity satisfy a specific crystal phase structure, a nepheline glass-ceramic possessing both high strength and good crystal structure stability is obtained. Figure 3 As shown, the XRD curves of the microcrystalline glass of Example 9 of this application and the chemically strengthened microcrystalline glass made from it are basically the same. This indicates that the crystal structure remains basically stable before and after chemical strengthening, without any significant phase transition. After chemical strengthening, this microcrystalline glass can be obtained with high mechanical strength and good breakage safety. Specifically, this chemically strengthened microcrystalline glass has both good impact resistance and compression resistance, is not prone to spontaneous breakage, and produces relatively large fragments after breakage, thus avoiding a large number of small fragments and effectively preventing safety hazards caused by small fragments. It can also meet the needs of temporary emergency use after breakage. In some embodiments, the mass percentage of nepheline in the microcrystalline glass relative to the sum of the masses of nepheline and sodium nepheline can be 3.5%, 4.14%, 5.0%, 5.55%, 5.66%, 5.69%, 5.87%, 5.97%, 6.12%, 6.68%, 7.5%, 8%, 9%, 10%, or 7.11%, or can be any range or subrange between any two of the above specific values, as long as the microcrystalline glass with the desired performance of this application can be obtained.

[0114] In some embodiments of this application, the glass-ceramic comprises a primary crystalline phase, sodium nepheline, and a secondary crystalline phase, nepheline. Sodium nepheline accounts for at least 80% of the total mass of all crystalline phases, preferably at least 90%. The mass of nepheline accounts for 3.5% to 15% of the sum of the masses of nepheline and sodium nepheline, preferably 3.5% to 10%, more preferably 3.5% to 7.5%, and even more preferably 3.5% to 5%. The crystallinity of the glass-ceramic is >60 wt%. Based on the mass percentage of oxides, the composition of the glass-ceramic includes: SiO2: 47-52%, Al2O3: 23-28%, P2O5: 3.5-4.5%, ZrO2: 1.5-4%, Na2O: 10-13%, K2O: 0-2%, Li2O: 3-5.5%, CaO: 0-2%, ZnO: 0-3%, B2O3: 0-3%, and Y2O3: 0-1.5%. It should be understood that, in specific implementation schemes, any of the above ranges can be combined with any other ranges, as long as the microcrystalline glass with the desired performance of this application can be obtained. Unrestricted by any theory, this application has discovered that by making a microcrystalline glass with high crystallinity satisfy a specific crystal phase structure, a nepheline microcrystalline glass with both high strength and good crystal structure stability can be obtained. After chemical strengthening, this microcrystalline glass can be obtained as a chemically strengthened microcrystalline glass with high mechanical strength and good breakage safety. Simultaneously, unrestricted by any theory, this application has discovered that the synergistic effect of key components with specific contents can achieve unexpected technical effects. For example, controlling the content of SiO2, Al2O3, Na2O, and Li2O within a specific range is beneficial for ensuring the formation of a specific nepheline crystal phase structure and avoiding melting difficulties; at the same time, controlling the Li2O content while controlling costs not only ensures that the microcrystalline glass with high crystallinity forms a specific stress structure after chemical strengthening, guaranteeing high strength, but also prevents excessive precipitation of the lithium nepheline crystal phase, thereby avoiding phase transitions in the microcrystalline glass during chemical strengthening. For example, ZrO2 and P2O5 work synergistically, which not only helps to refine the grains and promote uniform crystallization, but also helps to improve the fracture toughness of glass-ceramics.

[0115] In some embodiments of this application, the microcrystalline glass contains: 0 < nepheline content ≤ 10 wt%, and sodium nepheline content ≥ 55 wt%. The microcrystalline glass has a high content of crystalline phases or high crystallinity, which is beneficial for obtaining high intrinsic strength. Here, "nepheline content" refers to the mass content of the nepheline crystalline phase in the microcrystalline glass, and "sodium nepheline content" refers to the mass content of the sodium nepheline crystalline phase in the microcrystalline glass.

[0116] In some embodiments of this application, the glass-ceramic comprises a primary crystalline phase of sodium nepheline and a secondary crystalline phase of nepheline, wherein 0 < nepheline content ≤ 10 wt%, sodium nepheline content ≥ 55 wt%, and the mass of nepheline accounts for 3.5%~15% of the sum of the masses of nepheline and sodium nepheline, preferably 3.5%~10%, more preferably 3.5%~7.5%, and even more preferably 3.5%~5%, and the crystallinity of the glass-ceramic is > 60 wt%. Without being limited by any theory, this application has discovered that by making a glass-ceramic with high crystallinity satisfy a specific crystal phase structure, a nepheline glass-ceramic possessing both high strength and good crystal structure stability can be obtained. After chemical strengthening, this glass-ceramic can be obtained as a chemically strengthened glass-ceramic with high mechanical strength and good breakage safety. Specifically, this chemically strengthened glass-ceramic has good impact resistance and compression resistance, is not prone to spontaneous explosion, and produces relatively large fragments after breakage, thus effectively avoiding safety hazards caused by small fragments and meeting temporary emergency use needs after breakage.

[0117] In some embodiments of this application, the composition of the microcrystalline glass, based on the mass percentage of oxides, includes: SiO2: 47~52%, Al2O3: 23~28%, P2O5: 3.5~4.5%, ZrO2: 1.5~4%, Na2O: 10~13%, K2O: 0~2%, Li2O: 3~5.5%, CaO: 0~2%, ZnO: 0~3%, B2O3: 0~3%, Y2O3: 0~1.5%.

[0118] In some embodiments of this application, in the microcrystalline glass: 0 < nepheline content ≤ 8 wt%, 60 wt% ≤ sodium nepheline content ≤ 80 wt%; preferably, 3 wt% ≤ nepheline content ≤ 6 wt%, 63 wt% ≤ sodium nepheline content ≤ 75 wt%. In some embodiments, the mass content of nepheline can be 3 wt%, 3.20 wt%, 3.80 wt%, 3.90 wt%, 4.10 wt%, 4.50 wt%, 4.60 wt%, 4.70 wt%, 4.90 wt%, 5.40 wt%, 6 wt%, 8.00 wt%, or 10.00 wt%, or can be any range and sub-range between any two of the above specific values, as long as the microcrystalline glass with the desired performance of this application can be obtained. In some embodiments, the mass content of nepheline can be 60.00 wt%, 63 wt%, 64.70 wt%, 68.30 wt%, 68.40 wt%, 70.50 wt%, 70.60 wt%, 72.10 wt%, 74.00 wt%, 74.10 wt%, 75 wt%, or 80 wt%, or any range and sub-range between any two specific values ​​mentioned above, as long as the microcrystalline glass with the desired performance of this application is obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the microcrystalline glass with the desired performance of this application is obtained.

[0119] In some embodiments of this application, the composition of the microcrystalline glass, calculated as a percentage of oxides, satisfies the following content relationship:

[0120] 2.2≤Na2O / Li2O≤3, preferably 2.3≤Na2O / Li2O≤2.8;

[0121] 4.5≤Na2O / (P2O5×0.5)≤7.5, preferably 4.5≤Na2O / (P2O5×0.5)≤6.5;

[0122] 1.7≤Na2O / (Li2O+K2O)≤3, preferably 1.8≤Na2O / (Li2O+K2O)≤2.7.

[0123] In this application, by adjusting the glass composition to simultaneously satisfy the above three content relationships, it is beneficial to form a specific, stable crystalline phase structure as desired in this application.

[0124] In some embodiments, the Na₂O / Li₂O ratio in the glass-ceramic, calculated as a mass percentage of oxides, can be 2.2, 2.3, 2.4, 2.42, 2.45, 2.49, 2.53, 2.54, 2.57, 2.7, 2.8, 2.9, 3.0, or 2.60, or any range and sub-range between any two of the above specific values, as long as the glass-ceramic exhibiting the performance required by this application is obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other range, as long as the glass-ceramic exhibiting the performance required by this application is obtained.

[0125] In some embodiments, the value of Na2O / (P2O5×0.5) in the glass-ceramic, calculated as a mass percentage of oxides, can be 4.5, 4.81, 5.24, 5.48, 5.66, 5.68, 6.11, 6.5, 7, 7.5, or 6.12, or any range and sub-range between any two specific values ​​mentioned above, as long as the glass-ceramic exhibiting the performance required by this application is obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the glass-ceramic exhibiting the performance required by this application is obtained.

[0126] In some embodiments, the value of Na₂O / (Li₂O+K₂O) in the glass-ceramic, calculated as a mass percentage of oxides, can be 1.7, 1.75, 1.8, 1.85, 1.9, 1.91, 1.94, 2.03, 2.05, 2.42, 2.6, 2.7, 2.8, 2.9, 3.0, or 2.54, or any range and sub-range between any two specific values ​​mentioned above, as long as the glass-ceramic exhibiting the performance required by this application is obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the glass-ceramic exhibiting the performance required by this application is obtained.

[0127] In this application, SiO2, as the oxide forming the glass network, is an indispensable component of the glass network structure. Simultaneously, SiO2 is also essential as a crucial component of the nepheline crystalline phase. However, excessive SiO2 can increase the viscosity of the glass, causing difficulties in glass melting. To obtain the desired glass forming and crystallization effects, the SiO2 content in the microcrystalline glass is calculated as 47-52% by mass percentage of the oxide, preferably 48-51%.

[0128] In some embodiments, the SiO2 content in the glass-ceramic, calculated as a percentage by mass of oxides, can be 47.00%, 48%, 48.31%, 48.84%, 49.23%, 49.52%, 50.08%, 50.14%, 50.51%, 50.83%, 51%, or 52.00%, or any range and sub-range between any two of the above specific values, as long as the glass-ceramic exhibiting the performance required by this application is obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other range, as long as the glass-ceramic exhibiting the performance required by this application is obtained.

[0129] In this application, Al2O3 serves as an intermediate oxide in glass formation and is also an important component of the nepheline crystalline phase. An appropriate amount of Al2O3 can improve the thermal stability of the base glass and the glass-ceramic. However, if the Al2O3 content is too high, it hinders melting and reduces the content of the nepheline crystalline phase. To obtain the desired crystalline structure, the Al2O3 content in the glass-ceramic is calculated as a percentage of the oxide mass, ideally 23.5% to 27.5%.

[0130] In some embodiments, the Al2O3 content in the glass-ceramic, calculated as a percentage of oxide mass, can be 23.00%, 23.5%, 23.71%, 24.13%, 24.52%, 24.87%, 24.96%, 25.03%, 25.32%, 25.78%, 27.33%, 27.5%, or 28.00%, or any range and sub-range between any two specific values ​​mentioned above, as long as the glass-ceramic exhibiting the performance required by this application is obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other range, as long as the glass-ceramic exhibiting the performance required by this application is obtained.

[0131] In this application, P2O5 is the main nucleating agent and an essential component. If its content is too low or too high, the crystallization effect will be poor and the desired transparent glass-ceramic cannot be obtained. In order to obtain a transparent glass-ceramic with the desired crystalline structure, the P2O5 content in the glass-ceramic is calculated as 3.5-4.5% by mass percentage of oxides, preferably 3.7-4.3%.

[0132] In some embodiments, the P2O5 content in the glass-ceramic, calculated as a percentage by mass of oxides, can be 3.50%, 3.84%, 4.04%, 4.05%, 4.13%, 4.16%, 4.19%, 4.21%, 4.22%, 4.24%, 4.5%, 4.3%, 3.7%, or 4.00%, or any range and sub-range between any two specific values ​​mentioned above, as long as the glass-ceramic exhibiting the performance required by this application is obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the glass-ceramic exhibiting the performance required by this application is obtained.

[0133] In this application, ZrO2 can be used as a nucleating agent and toughening agent to reduce grain size and increase the toughness of the glass-ceramic. However, when its content is too high, it will inhibit the precipitation of nepheline crystalline phase. In order to obtain the desired crystalline structure, the ZrO2 content in the glass-ceramic is calculated as 1.5~4.0% by mass percentage of oxides, preferably 1.5~3.8%.

[0134] In some embodiments, the ZrO2 content in the glass-ceramic, calculated as a percentage by mass of oxides, can be 1.50%, 1.61%, 1.83%, 2.66%, 2.69%, 3.30%, 3.51%, 3.59%, 3.63%, 3.8%, or 4.00%, or any range and sub-range between any two specific values ​​mentioned above, as long as the glass-ceramic exhibiting the performance required by this application is obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the glass-ceramic exhibiting the performance required by this application is obtained.

[0135] In this application, Na₂O, as an external oxide in the network, provides free oxygen, improves the viscosity of the glass, and promotes the melting and clarification of the molten glass. Simultaneously, Na₂O is the main component of nepheline. However, excessive Na₂O may cause a large amount of nepheline crystal phase to precipitate in the glass, affecting the lithium-sodium ion exchange efficiency and chemical stability. To obtain the desired crystal structure, the Na₂O content in the microcrystalline glass is calculated as 10-13% by mass percentage of the oxide, preferably 10-12.8%.

[0136] In some embodiments, the Na₂O content in the glass-ceramic, calculated as a percentage by mass of oxides, can be 10.00%, 10.12%, 10.97%, 11.39%, 11.48%, 11.74%, 11.99%, 12.00%, 12.37%, 12.8%, 12.63%, or 13.00%, or any range and sub-range between any two of the above specific values, as long as the glass-ceramic exhibiting the performance required by this application is obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other range, as long as the glass-ceramic exhibiting the performance required by this application is obtained.

[0137] In this application, Li₂O, as the network oxide in glass formation, provides free oxygen, improves the viscosity of the glass, promotes the melting and clarification of the molten glass, and can also undergo ion exchange with the molten salt bath, making it a significant factor affecting glass stress. Furthermore, Li₂O is a major component of nepheline. However, excessive Li₂O may lead to the precipitation of a large amount of nepheline crystal phase in the glass, affecting the stability of the crystal structure and consequently the strength of the chemically strengthened glass-ceramic. To obtain the desired crystal structure and excellent performance, the Li₂O content in the glass-ceramic is calculated as 3-5.5% by mass percentage of the oxide, preferably 3.5-5.2%.

[0138] In some embodiments, the Li₂O content in the glass-ceramic, calculated as a percentage by mass of oxides, can be 3.00%, 3.5%, 3.99%, 4.41%, 4.51%, 4.67%, 4.68%, 4.79%, 4.85%, 4.89%, 5.11%, 5.2%, or 5.50%, or any range and sub-range between any two of the above specific values, as long as the glass-ceramic exhibiting the performance required by this application is obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the glass-ceramic exhibiting the performance required by this application is obtained.

[0139] In this application, an appropriate amount of K2O can reduce the high-temperature viscosity and crystallization tendency of the base glass. Furthermore, it can promote the formation of nepheline crystals during the crystallization process. However, excessive K2O will inhibit the precipitation of the nepheline crystalline phase. To obtain the desired properties and crystal structure, the K2O content in the microcrystalline glass is calculated as a percentage of oxide mass, preferably 0-1.5%.

[0140] In some embodiments, the K₂O content in the glass-ceramic, calculated as a percentage by mass of oxides, can be 0, 0.28%, 0.94%, 1.34%, 1.37%, 1.40%, 1.5%, or 2.00%, or any range and sub-range between any two of the above specific values, as long as the glass-ceramic exhibiting the performance required by this application is obtained. It should be understood that, in specific embodiments, any of the above ranges can be combined with any other range, as long as the glass-ceramic exhibiting the performance required by this application is obtained.

[0141] In this application, an appropriate amount of CaO can reduce high-temperature viscosity, which is beneficial for glass forming, and at the same time, it can enhance the network structure and improve the stress gain during the strengthening process. However, excessive CaO will cause a sharp decrease in the crystallinity of the glass, affecting the intrinsic strength of the glass-ceramic. In order to obtain the desired properties and crystal phase structure, the CaO content in the glass-ceramic is 0~2%, preferably 0~1.5%, calculated as a percentage by mass of oxides.

[0142] In some embodiments, the CaO content in the glass-ceramic, calculated as a percentage of oxide mass, can be 0, 0.49%, 0.80%, 1.23%, 1.5%, or 2.00%, or any range and sub-range between any two specific values ​​mentioned above, as long as the glass-ceramic exhibiting the performance required by this application is obtained. It should be understood that, in specific embodiments, any of the above ranges can be combined with any other range, as long as the glass-ceramic exhibiting the performance required by this application is obtained.

[0143] In this application, an appropriate amount of B2O3 serves as the network oxide of the glass, typically filling the voids in the silicon-oxygen tetrahedral framework, which improves the thermal and chemical stability of the glass. However, excessive B2O3 can inhibit the precipitation of the nepheline crystalline phase. To obtain the desired properties and crystal structure, the B2O3 content in the microcrystalline glass is calculated as 0-3% by mass percentage of the oxide, preferably 0-2.1%.

[0144] In some embodiments, the B2O3 content in the glass-ceramic, calculated as a percentage of oxide by mass, can be 0, 1.04%, 1.99%, 2.07%, 2.1%, or 3.00%, or any range and sub-range between any two of the above specific values, as long as the glass-ceramic exhibiting the performance required by this application is obtained. It should be understood that, in specific embodiments, any of the above ranges can be combined with any other range, as long as the glass-ceramic exhibiting the performance required by this application is obtained.

[0145] In this application, an appropriate amount of ZnO can reduce the coefficient of thermal expansion of the glass and improve its thermal stability. Furthermore, it can promote crystallization. However, excessive ZnO can easily lead to crystallization during the molding of the base glass. To obtain the desired properties and crystal structure, the ZnO content in the microcrystalline glass is calculated as a percentage of oxide mass, ideally 0-0.5%.

[0146] In some embodiments, the ZnO content in the glass-ceramic can be 0, 0.30%, 0.5%, or 3.00% by mass percentage of oxides, or it can be any range or sub-range between any two of the above specific values, as long as the glass-ceramic with the desired performance of this application is obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the glass-ceramic with the desired performance of this application is obtained.

[0147] In this application, an appropriate amount of Y₂O₃ is used as the network oxide of the glass, which can improve the strength and elastic modulus of the glass, while lowering the melting temperature. However, excessive Y₂O₃ can easily increase the crystallization tendency of the base glass and inhibit the precipitation of nepheline crystal phase in the glass-ceramic. In order to obtain the desired performance and crystal structure, the Y₂O₃ content in the glass-ceramic is calculated as 0~1.5% by mass percentage of oxide, preferably 0~0.5%.

[0148] In some embodiments, the Y₂O₃ content in the glass-ceramic, calculated as a percentage by mass of oxide, can be 0, 0.39%, 0.5%, 1.00%, or 1.50%, or can be any range or sub-range between any two of the above specific values, as long as the glass-ceramic exhibiting the performance required by this application is obtained. It should be understood that, in specific embodiments, any of the above ranges can be combined with any other range, as long as the glass-ceramic exhibiting the performance required by this application is obtained.

[0149] In some embodiments of this application, the crystallinity of the glass-ceramic is 65wt% to 80wt%, preferably 68wt% to 78wt%. A high crystalline phase content or crystallinity in the glass-ceramic is beneficial for obtaining high intrinsic strength.

[0150] In some embodiments, the crystallinity of the glass-ceramic can be 60.1 wt%, 65.00 wt%, 68 wt%, 68.50 wt%, 68.60 wt%, 72.40 wt%, 73.30 wt%, 75.20 wt%, 75.90 wt%, 76.60 wt%, 77.30 wt%, 78 wt%, 78.70 wt%, or 80.00 wt%, or any range and sub-range between any two specific values ​​mentioned above, as long as the glass-ceramic exhibiting the performance required by this application is obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other range, as long as the glass-ceramic exhibiting the performance required by this application is obtained.

[0151] In this application, the average grain size in the microcrystalline glass does not exceed 50 nm, preferably 10 nm to 40 nm, and more preferably 20 nm to 30 nm. A smaller grain size is beneficial for the microcrystalline glass to achieve excellent optical performance.

[0152] In some embodiments, the average grain size of the glass-ceramic can be 10.00 nm, 20.00 nm, 24.6 nm, 24.8 nm, 25.7 nm, 26.6 nm, 27.2 nm, 28.0 nm, 29.3 nm, 29.8 nm, 30.00 nm, or 40.00 nm, or can be any range or sub-range between any two specific values ​​mentioned above, as long as the glass-ceramic exhibiting the performance required by this application can be obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other range, as long as the glass-ceramic exhibiting the performance required by this application can be obtained.

[0153] In some embodiments of this application, the proportion of the nepheline phase in the glass-ceramic is 80 wt% to less than 100 wt% of all crystalline phases. In some embodiments, the proportion of the nepheline phase in the glass-ceramic can be 80 wt%, 90 wt%, 92.89 wt%, 93.32 wt%, 93.88 wt%, 94.03 wt%, 94.13 wt%, 94.31 wt%, 94.34 wt%, 94.45 wt%, 95.86 wt%, or 96 wt%, or any range and sub-range between any two specific values ​​mentioned above, as long as the glass-ceramic with the desired performance of this application is obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other range, as long as the glass-ceramic with the desired performance of this application is obtained.

[0154] In some embodiments of this application, the refractive index of the microcrystalline glass is 1.53 to 1.55. In some embodiments, the refractive index of the microcrystalline glass can be 1.530, 1.534, 1.535, 1.536, 1.537, 1.538, 1.539, 1.542, or 1.550, or can be any range or sub-range between any two specific values ​​mentioned above, as long as the microcrystalline glass with the desired performance of this application can be obtained.

[0155] In some embodiments of this application, the density of the microcrystalline glass is 2.5~2.7 g / cm³. 3 .

[0156] In some embodiments of this application, when the thickness of the glass-ceramic is 0.35mm to 0.6mm, the haze of the glass-ceramic is <0.20%. In some embodiments, when the thickness of the glass-ceramic is 0.35mm to 0.6mm, the haze of the glass-ceramic can be 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, or 0.18%, or can be any range and sub-range between any two specific values ​​mentioned above, as long as the glass-ceramic with the performance required by this application can be obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the glass-ceramic with the performance required by this application can be obtained.

[0157] In some embodiments of this application, when the thickness of the glass-ceramic is 0.35mm to 0.6mm, the b-value of the glass-ceramic is <0.9, preferably <0.8, and more preferably b-value ≤0.75. In some embodiments, when the thickness of the glass-ceramic is 0.35mm to 0.6mm, the b-value of the glass-ceramic can be 0.56, 0.58, 0.59, 0.60, 0.61, 0.64, 0.70, 0.72, or 0.73, or can be any range and sub-range between any two specific values ​​mentioned above, as long as the glass-ceramic with the performance required by this application can be obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the glass-ceramic with the performance required by this application can be obtained.

[0158] In some embodiments of this application, the microcrystalline glass is transparent in the visible light wavelength range. "Transparent" means that the average transmittance in the visible light wavelength range is greater than or equal to 85%. Preferably, when the thickness of the microcrystalline glass is 0.35~0.6mm, the transmittance of the microcrystalline glass at a wavelength of 550nm is ≥85%, more preferably ≥90%, and even more preferably ≥90.5%. In some embodiments, when the thickness of the microcrystalline glass is 0.35~0.6mm, the transmittance of the microcrystalline glass at a wavelength of 550nm can be 85%, 86%, 87%, 88%, 89%, 90.5%, 90.82%, 90.85%, 90.89%, 90.91%, 90.95%, 91.02%, 91.05%, or 91.10%, or any range and sub-range between any two specific values ​​mentioned above, as long as the microcrystalline glass with the performance required by this application can be obtained. It should be understood that, in specific implementations, any of the above ranges can be combined with any other ranges, as long as the microcrystalline glass with the desired performance of this application can be obtained. In this application, the optical properties of the microcrystalline glass before and after chemical strengthening, such as transmittance, are substantially the same, such as... Figure 9 As shown, the transmittance curves of the microcrystalline glass of Example 9 and the chemically strengthened microcrystalline glass obtained by chemical strengthening treatment of the microcrystalline glass are basically the same.

[0159] In some embodiments of this application, the Young's modulus of the glass-ceramic is ≥90 GPa, preferably 90 GPa to 105 GPa. In some embodiments, the Young's modulus of the glass-ceramic can be 90 GPa, 91 GPa, 92 GPa, 93 GPa, 94 GPa, 95 GPa, 96 GPa, 97 GPa, 98 GPa, 99 GPa, or 105 GPa, or any range and sub-range between any two specific values ​​mentioned above, as long as the glass-ceramic with the desired properties of this application is obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the glass-ceramic with the desired properties of this application is obtained. It should be understood that the chemical strengthening process mainly improves mechanical properties (such as drop resistance, compression resistance, etc.) by introducing a compressive stress layer on the surface of the glass-ceramic, while the intrinsic mechanical properties of the glass-ceramic (such as Young's modulus, Vickers hardness, etc.) remain basically stable before and after chemical strengthening.

[0160] II. A method for preparing microcrystalline glass

[0161] In some embodiments of this application, a method for preparing microcrystalline glass is provided, comprising:

[0162] The raw material components are prepared according to the aforementioned oxide ratios, melted, cooled, and annealed to obtain the base glass; the base glass is then subjected to heat treatment, for example, nucleation and crystallization treatments, to obtain glass-ceramics.

[0163] In some embodiments of this application, the temperature is increased to the nucleation temperature at a heating rate of 3°C / min to 15°C / min, the nucleation temperature is 640°C to 660°C, and the nucleation time is 10 min to 1440 min. In some embodiments, the nucleation temperature can be 640°C, 645°C, 650°C, 655°C, or 660°C, or any range or subrange between any two specific values ​​mentioned above, as long as the microcrystalline glass with the desired performance of this application is obtained; the nucleation treatment time can be 10 min, 180 min, 240 min, 300 min, 1200 min, or 1440 min, or any range or subrange between any two specific values ​​mentioned above, as long as the microcrystalline glass with the desired performance of this application is obtained; the heating rate can be 3°C / min, 4°C / min, 5°C / min, 6°C / min, 7°C / min, 8°C / min, 9°C / min, 10°C / min, or 15°C / min, or any range or subrange between any two specific values ​​mentioned above, as long as the microcrystalline glass with the desired performance of this application is obtained; it should be understood that, in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the microcrystalline glass with the desired performance of this application is obtained.

[0164] In some embodiments of this application, the temperature is increased to the crystallization temperature at a heating rate of 3°C / min to 15°C / min, the crystallization temperature is 725°C to 750°C, and the crystallization time is 5 min to 1440 min. In some embodiments, the crystallization temperature can be 725℃, 730℃, 735℃, 740℃, 745℃, or 750℃, or any range and sub-range between any two specific values ​​mentioned above, as long as the microcrystalline glass with the desired performance of this application is obtained; the crystallization treatment time can be 5 min, 10 min, 180 min, 240 min, 300 min, 1200 min, or 1440 min, or any range and sub-range between any two specific values ​​mentioned above, as long as the microcrystalline glass with the desired performance of this application is obtained; the heating rate can be 3℃ / min, 4℃ / min, 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, 10℃ / min, or 15℃ / min, or any range and sub-range between any two specific values ​​mentioned above, as long as the microcrystalline glass with the desired performance of this application is obtained; it should be understood that, in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the microcrystalline glass with the desired performance of this application is obtained.

[0165] III. A chemically strengthened microcrystalline glass

[0166] In some embodiments of this application, a chemically strengthened glass-ceramic is provided, which is obtained by chemically strengthening the aforementioned glass-ceramic. It should be understood that the surface composition of the chemically strengthened glass-ceramic obtained after chemical strengthening may differ from the composition of the glass-ceramic before chemical strengthening. This is because ion exchange occurs during the chemical strengthening process, and during ion exchange, one type of ion on the surface of the glass-ceramic is replaced by another type of ion, such as alkali metal ions (e.g., Li) on the surface of the glass-ceramic. + Or Na + They will be respectively affected by larger alkali metal ions (e.g., Na+). + or K + However, in specific embodiments, the glass composition and phase structure at or near the depth or thickness center of the chemically strengthened glass-ceramic will still have the composition and phase structure of the glass-ceramic. That is to say, in this application, the composition and phase structure at the center of the chemically strengthened glass-ceramic, or the composition and phase structure of the tensile stress layer that has not undergone substantial ion exchange, are the same as or substantially the same as those of the untreated glass-ceramic.

[0167] In some embodiments of this application, the chemically strengthened glass-ceramic includes a tensile stress layer and a compressive stress layer. The crystallinity of the chemically strengthened glass-ceramic is >60 wt%. The chemically strengthened glass-ceramic includes a primary crystalline phase of nepheline and a secondary crystalline phase of nepheline. The mass of nepheline accounts for 3.5% to 15% of the sum of the masses of nepheline and nepheline, preferably 3.5% to 7.3%, and more preferably 4% to 7%. The chemically strengthened glass-ceramic of this application is made from a glass-ceramic that satisfies a specific crystal phase structure. Without being limited by any theory, this application has found that because this glass-ceramic possesses both high strength and good crystal structure stability, it does not undergo significant phase transformation after chemical strengthening treatment, and the crystal phase structure remains basically stable. This results in a chemically strengthened glass-ceramic with high mechanical strength and good breakage safety. Simultaneously, this chemically strengthened glass-ceramic also possesses good impact resistance and compression resistance, is not prone to spontaneous explosion, and produces relatively large fragments after breakage, thus avoiding the safety hazards caused by small fragments and meeting temporary emergency use needs after breakage.

[0168] In some embodiments of this application, the chemically strengthened glass-ceramic includes a tensile stress layer and a compressive stress layer. The chemically strengthened glass-ceramic includes a primary crystalline phase, nepheline, and a secondary crystalline phase, cepheline. The mass percentage of nepheline in all crystalline phases is not less than 80%, preferably not less than 90%. The mass percentage of cepheline accounts for 3.5% to 15% of the sum of the masses of cepheline and nepheline, preferably 3.5% to 7.3%, more preferably 4% to 7%. The crystallinity of the chemically strengthened glass-ceramic is >60 wt%.

[0169] The composition of the chemically strengthened glass-ceramic tensile stress layer or the composition at the center of the chemically strengthened glass-ceramic, based on the mass percentage of oxides, includes:

[0170] SiO2: 47~52%, Al2O3: 23~28%, P2O5: 3.5~4.5%, ZrO2: 1.5~4%, Na2O: 10~13% , K2O: 0~2%, Li2O: 3~5.5%, CaO: 0~2%, ZnO: 0~3%, B2O3: 0~3%, Y2O3: 0~1.5%.

[0171] In some embodiments of this application, the chemically strengthened glass-ceramic includes a tensile stress layer and a compressive stress layer, and comprises a primary crystalline phase of nepheline and a secondary crystalline phase of nepheline; wherein, 0 < nepheline content ≤ 10 wt%, nepheline content ≥ 55 wt%, and the mass of nepheline accounts for 3.5% to 15% of the sum of the masses of nepheline and nepheline, preferably 3.5% to 7.3%, more preferably 4% to 7%, and the crystallinity of the chemically strengthened glass-ceramic is > 60 wt%. Here, "nepheline content" refers to the mass content of the nepheline crystalline phase in the chemically strengthened glass-ceramic, and "nepheline content" refers to the mass content of the nepheline crystalline phase in the chemically strengthened glass-ceramic.

[0172] In some embodiments of this application, in the chemically strengthened microcrystalline glass: 0 < nepheline content ≤ 8 wt%, 60 wt% ≤ sodium nepheline content ≤ 80 wt%, preferably, 3 wt% ≤ nepheline content ≤ 6 wt%, and 63 wt% ≤ sodium nepheline content ≤ 75 wt%.

[0173] In some embodiments, the mass content of nepheline in the chemically strengthened glass-ceramic can be 3 wt%, 3.20 wt%, 3.80 wt%, 3.90 wt%, 4.10 wt%, 4.50 wt%, 4.60 wt%, 4.70 wt%, 4.90 wt%, 5.40 wt%, 6 wt%, 8.00 wt%, or 10.00 wt%, or can be any range and subrange between any two of the above specific values, as long as the chemically strengthened glass-ceramic with the properties required by this application can be obtained. In some embodiments, the sodium nepheline content in the chemically strengthened glass-ceramic can be 60.00 wt%, 63 wt%, 64.70 wt%, 68.30 wt%, 68.40 wt%, 70.50 wt%, 70.60 wt%, 72.10 wt%, 74.00 wt%, 74.10 wt%, 75 wt%, or 80 wt%, or any range or subrange between any two of the above specific values, as long as the chemically strengthened glass-ceramic with the desired performance of this application is obtained. In some embodiments, the percentage of lithium nepheline in the chemically strengthened glass-ceramic relative to the sum of the masses of lithium nepheline and sodium nepheline can be 3.5%, 4.14%, 5.0%, 5.55%, 5.66%, 5.69%, 5.87%, 5.97%, 6.12%, 6.68%, or 7.11%, or any range or subrange between any two of the above specific values, as long as the chemically strengthened glass-ceramic with the desired performance of this application is obtained. It should be understood that, in specific implementation schemes, any of the above ranges can be combined with any other ranges, as long as the chemically strengthened microcrystalline glass with the desired performance of this application can be obtained.

[0174] In some embodiments of this application, the composition of the tensile stress layer of the chemically strengthened glass-ceramic or the composition at the center of the chemically strengthened glass-ceramic, based on the mass percentage of oxides, satisfies the following:

[0175] 2.2≤Na2O / Li2O≤3, preferably 2.3≤Na2O / Li2O≤2.8;

[0176] 4.5≤Na2O / (P2O5×0.5)≤7.5, preferably 4.5≤Na2O / (P2O5×0.5)≤6.5;

[0177] 1.7≤Na2O / (Li2O+K2O)≤3, preferably 1.8≤Na2O / (Li2O+K2O)≤2.7.

[0178] In some embodiments, the composition of the tensile stress layer of the chemically strengthened glass-ceramic or the composition at the center of the chemically strengthened glass-ceramic, based on the mass percentage of oxides, includes the following: the Na₂O / Li₂O value can be 2.2, 2.3, 2.4, 2.42, 2.45, 2.49, 2.53, 2.54, 2.57, 2.7, 2.8, 2.9, 3.0, or 2.60, or any range or sub-range between any two specific values ​​mentioned above, as long as the chemically strengthened glass-ceramic with the desired performance of this application is obtained; the Na₂O / (P₂O₅×0.5) value can be 4.5, 4.81, 5.24, 5.48, 5.66, 5.68, 6.11, 6.5, 7, 7.5, or 6.12, or any range or sub-range between any two specific values ​​mentioned above, as long as the chemically strengthened glass-ceramic with the desired performance of this application is obtained; the Na₂O / (Li₂O+K₂O) value can also be... The value can be 1.7, 1.75, 1.8, 1.85, 1.9, 1.91, 1.94, 2.03, 2.05, 2.42, 2.6, 2.7, 2.8, 2.9, 3.0, or 2.54, or any range or subrange between any two specific values ​​mentioned above, as long as the chemically strengthened glass-ceramic with the desired performance of this application can be obtained. It should be understood that, in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the chemically strengthened glass-ceramic with the desired performance of this application can be obtained.

[0179] In some embodiments of this application, the composition of the chemically strengthened glass-ceramic tensile stress layer or the composition at the center of the chemically strengthened glass-ceramic, based on the mass percentage of oxides, includes:

[0180] SiO2: 47~52%, Al2O3: 23~28%, P2O5: 3.5~4.5%, ZrO2: 1.5~4%, Na2O: 10~13% , K2O: 0~2%, Li2O: 3~5.5%, CaO: 0~2%, ZnO: 0~3%, B2O3: 0~3%, Y2O3: 0~1.5%.

[0181] In some embodiments of this application, the chemically strengthened glass-ceramic, based on the mass percentage of oxides, satisfies the following: In the composition of the tensile stress layer of the chemically strengthened glass-ceramic or in the composition at the center of the chemically strengthened glass-ceramic, based on the mass percentage of oxides: the content of SiO2 is 48-51%; and / or, the content of Al2O3 is 23.5-27.5%; and / or, the content of P2O5 is 3.7-4.3%; and / or, the content of ZrO2 is 1.5-3.8%; and / or, the content of Na2O is 10-12.8%; and / or, the content of K2O is 0-1.5%; and / or, the content of Li2O is 3.5-5.2%; and / or, the content of CaO is 0-1.5%; and / or, the content of ZnO is 0-0.5%; and / or, the content of B2O3 is 0-2.1%; and / or, the content of Y2O3 is 0-0.5%.

[0182] In some embodiments of this application, the crystallinity of the chemically strengthened glass-ceramic is 65wt%~80wt%, more preferably 67wt%~78wt%; and / or, in the chemically strengthened glass-ceramic, the average grain size is not more than 50nm, preferably 10nm~40nm, more preferably 20nm~30nm; and / or, in the chemically strengthened glass-ceramic, the proportion of the nepheline phase in all phases is 80wt%~less than 100wt%.

[0183] In some embodiments, the chemically strengthened glass-ceramic satisfies the following requirements: crystallinity can be 60.10 wt%, 67.70 wt%, 67.80 wt%, 71.60 wt%, 73.00 wt%, 73.80 wt%, 74.50 wt%, 75.20 wt%, 76.60 wt%, 77.70 wt%, or 80.00 wt%, or any range and sub-range between any two specific values ​​mentioned above, as long as the chemically strengthened glass-ceramic with the desired performance of this application can be obtained; the average grain size can be 10.00 nm, 20.00 nm, 24.6 nm, 24.8 nm, 25.7 nm, 26.6 nm, 27.2 nm, 28.0 nm, 29 nm, or 29 nm. The nanometers can be 0.3 nm, 29.8 nm, 30.00 nm, or 40.00 nm, or any range and sub-range between any two specific values ​​mentioned above, as long as the chemically strengthened glass-ceramic with the desired performance of this application is obtained; the proportion of the nepheline phase in all phases can be 80 wt%, 90 wt%, 93.09 wt%, 93.29 wt%, 94.10 wt%, 94.21 wt%, 94.23 wt%, 94.24 wt%, 94.27 wt%, 94.31 wt%, 95.56 wt%, or 96 wt%, or any range and sub-range between any two specific values ​​mentioned above, as long as the chemically strengthened glass-ceramic with the desired performance of this application is obtained. It should be understood that, in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the chemically strengthened glass-ceramic with the desired performance of this application is obtained.

[0184] In some embodiments of this application, it is preferred that the crystal phase of the chemically strengthened microcrystalline glass does not contain potassium nepheline.

[0185] In some embodiments of this application, in the chemically strengthened microcrystalline glass: 0 < nepheline content ≤ 10 wt%, preferably, 0 < nepheline content ≤ 8 wt%, more preferably, 3 wt% ≤ nepheline content ≤ 6 wt%; sodium nepheline content ≥ 55 wt%, preferably, 60 wt% ≤ sodium nepheline content ≤ 80 wt%, more preferably, 63 wt% ≤ sodium nepheline content ≤ 75 wt%. In some embodiments, the content of nepheline in the chemically strengthened glass-ceramic can be 3wt%, 3.40wt%, 3.90wt%, 4.00wt%, 4.10wt%, 4.20wt%, 4.30wt%, 4.50wt%, 4.90wt%, 5.5wt%, 6wt%, or 5.20wt%, or any range and subrange between any two specific values ​​mentioned above, as long as the chemically strengthened glass-ceramic with the performance required by this application can be obtained; the content of sodium nepheline can be 60wt%, 63wt%, 63.80wt%, 67.50wt%, 68.10wt%, 69.60wt%, 70.00wt%, 70.20wt%, 73.20wt%, 74wt%, 75wt%, or 73.40wt%, or any range and subrange between any two specific values ​​mentioned above, as long as the chemically strengthened glass-ceramic with the performance required by this application can be obtained. It should be understood that, in specific implementation schemes, any of the above ranges can be combined with any other ranges, as long as the chemically strengthened microcrystalline glass with the desired performance of this application can be obtained.

[0186] This application does not limit the thickness of the microcrystalline glass or chemically strengthened microcrystalline glass; those skilled in the art can select it according to their needs. Exemplarily, in some embodiments of this application, the thickness t of the chemically strengthened microcrystalline glass can be 0.35mm~1.0mm, 0.4mm~0.7mm, or 0.45mm~0.55mm, etc. For example, the thickness can be 0.35mm, 0.40mm, 0.45mm, 0.50mm, 0.55mm, 0.60mm, 0.65mm, 0.70mm, 0.75mm, 0.80mm, 0.85mm, 0.90mm, 0.95mm, or 1.00mm, or it can be any range and sub-range between any two specific values ​​mentioned above, as long as the chemically strengthened microcrystalline glass with the desired performance of this application can be obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other range, as long as the chemically strengthened microcrystalline glass with the desired performance of this application can be obtained.

[0187] In some embodiments of this application, when the thickness of the chemically strengthened glass-ceramic is (0.5±0.01) mm, the chemically strengthened glass-ceramic satisfies the following: tensile stress linear density CT_LD ≥ 35000 MPa / mm, preferably CT_LD is 35000 MPa / mm~50000 MPa / mm; and / or, CS_50 ≥ 100 MPa, preferably CS_50 is 100 MPa~150 MPa, where CS_50 refers to the compressive stress value at a depth of 50 μm from the main surface of the chemically strengthened glass-ceramic, in MPa; and / or, |CT_AV| ≥ 75 MPa, preferably |CT_AV| is 75 MPa~100 MPa, where |CT_AV| is the absolute value of the average tensile stress, in MPa; and / or, DOL_K ≥ 6 μm, preferably DOL_K is 6 μm. ~15μm, DOL_K refers to the depth of potassium ions that have entered the glass interior through ion exchange, measured from the main surface of the chemically strengthened glass-ceramic; and / or, the compressive stress layer depth DOL_0 > 95μm, preferably DOL_0 is 100μm~120μm.

[0188] In some embodiments, when the thickness of the chemically strengthened glass-ceramic is (0.5 ± 0.01) mm, the compressive stress layer depth DOL_0 of the chemically strengthened glass-ceramic can be 106.9 μm, 107.9 μm, 108.2 μm, 109.2 μm, 109.5 μm, 110.4 μm, 110.5 μm, 111.2 μm, or 111.4 μm, or can be any range and sub-range between any two specific values ​​mentioned above, as long as the chemically strengthened glass-ceramic with the desired performance of this application can be obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the chemically strengthened glass-ceramic with the desired performance of this application can be obtained.

[0189] In some embodiments, when the thickness of the chemically strengthened glass-ceramic is (0.5 ± 0.01) mm, the tensile stress linear density CT_LD of the chemically strengthened glass-ceramic can be 36325.0 MPa / mm, 36624.6 MPa / mm, 38946.6 MPa / mm, 39511.0 MPa / mm, 39525.1 MPa / mm, 39559.9 MPa / mm, 39983.4 MPa / mm, 41781.3 MPa / mm, or 41854.6 MPa / mm, or any range and sub-range between any two specific values ​​mentioned above, as long as the chemically strengthened glass-ceramic with the desired performance of this application can be obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the chemically strengthened glass-ceramic with the desired performance of this application can be obtained.

[0190] In some embodiments, when the thickness of the chemically strengthened glass-ceramic is (0.5±0.01) mm, the CS_50 of the chemically strengthened glass-ceramic can be 107.8 MPa, 110.4 MPa, 112.9 MPa, 113.2 MPa, 113.5 MPa, 116.2 MPa, 120.6 MPa, 121.3 MPa, or 136.5 MPa, or any range and sub-range between any two specific values ​​mentioned above, as long as the chemically strengthened glass-ceramic with the performance required by this application can be obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the chemically strengthened glass-ceramic with the performance required by this application can be obtained.

[0191] In some embodiments, when the thickness of the chemically strengthened glass-ceramic is (0.5±0.01) mm, the |CT_AV| of the chemically strengthened glass-ceramic can be 75 MPa, 79.8 MPa, 80.6 MPa, 84.3 MPa, 84.6 MPa, 85.3 MPa, 86.3 MPa, 87.3 MPa, 88.6 MPa, or 89.2 MPa, or any range and sub-range between any two specific values ​​mentioned above, as long as the chemically strengthened glass-ceramic with the performance required by this application can be obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the chemically strengthened glass-ceramic with the performance required by this application can be obtained.

[0192] In some embodiments, when the thickness of the chemically strengthened glass-ceramic is (0.5 ± 0.01) mm, the DOL_K of the chemically strengthened glass-ceramic can be 6.3 μm, 7.4 μm, 7.9 μm, 8.1 μm, 8.2 μm, 8.5 μm, 8.6 μm, or 10.5 μm, or can be any range or sub-range between any two of the above specific values, as long as the chemically strengthened glass-ceramic with the performance required by this application can be obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other range, as long as the chemically strengthened glass-ceramic with the performance required by this application can be obtained.

[0193] In some embodiments of this application, the chemically strengthened glass-ceramic satisfies: 0.20≤DOL_0 / t≤0.25, where DOL_0 is the compressive stress layer depth and t is the thickness of the chemically strengthened glass-ceramic; and / or, surface CS≥1400MPa, preferably 1500MPa~1900MPa.

[0194] In some embodiments, in the chemically strengthened glass-ceramic, DOL_0 / t can be 0.20, 0.21, 0.22, 0.23, 0.24, or 0.25, or can be any range or sub-range between any two specific values ​​mentioned above, as long as the chemically strengthened glass-ceramic with the desired performance of this application can be obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other range, as long as the chemically strengthened glass-ceramic with the desired performance of this application can be obtained.

[0195] In some embodiments, when the thickness of the chemically strengthened glass-ceramic is (0.5±0.01) mm, the surface pressure (CS) of the chemically strengthened glass-ceramic can be 1586.2 MPa, 1592.6 MPa, 1622.6 MPa, 1690.8 MPa, 1699.0 MPa, 1699.1 MPa, 1740.2 MPa, 1743.4 MPa, or 1746.4 MPa, or any range and sub-range between any two specific values ​​mentioned above, as long as the chemically strengthened glass-ceramic with the desired performance of this application can be obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the chemically strengthened glass-ceramic with the desired performance of this application can be obtained.

[0196] In some embodiments of this application, the chemically strengthened glass-ceramic satisfies the following conditions: When the chemically strengthened glass-ceramic is subjected to a sandpaper drop test using 120-grit sandpaper, and the thickness is not more than 0.60 mm, preferably 0.49 mm to 0.55 mm, and more preferably 0.49 mm to 0.51 mm, the average drop height of the chemically strengthened glass-ceramic is ≥0.9 m, and when the chemically strengthened glass-ceramic breaks upon drop, the average size of the longest side of the fragments is ≥15 mm; and / or,

[0197] The chemically strengthened glass-ceramic is pressed using a 10mm diameter round-headed metal pressure bar. The static compressive strength of the single bar that the chemically strengthened glass-ceramic can withstand is tested. When the thickness does not exceed 0.60mm, preferably 0.49mm~0.55mm, and more preferably 0.49mm~0.51mm, the static compressive strength of the single bar that the chemically strengthened glass-ceramic can withstand is ≥350N, preferably 350~500N; and / or,

[0198] A 32g steel ball is used to conduct a drop ball impact test on the chemically strengthened microcrystalline glass. When the thickness does not exceed 0.60mm, preferably when the thickness is 0.49mm~0.55mm, and more preferably when the thickness is 0.49mm~0.51mm, the drop ball impact height when the chemically strengthened microcrystalline glass breaks is ≥1.0m, preferably 1.0~1.5m.

[0199] In some embodiments of this application, the chemically strengthened glass-ceramic is subjected to a sandpaper drop test using 120-grit sandpaper. When the thickness of the chemically strengthened glass-ceramic is (0.5±0.01) mm, the average sandpaper drop resistance of the chemically strengthened glass-ceramic is ≥0.9 m, and when the chemically strengthened glass-ceramic breaks upon drop, the average size of the longest side of the fragments is ≥15 mm. In some embodiments, the average size of the longest side of the fragments can be 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm, 21 mm, 22 mm, 23 mm, 24 mm, or 25 mm, or any range and sub-range between any two specific values ​​mentioned above, as long as the chemically strengthened glass-ceramic with the performance required by this application can be obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the chemically strengthened glass-ceramic with the performance required by this application can be obtained.

[0200] In some embodiments of this application, the chemically strengthened glass-ceramic is compressed using a 10mm diameter round-headed metal pressure bar, and the static compressive strength of a single bar that the chemically strengthened glass-ceramic can withstand is tested. When the thickness of the chemically strengthened glass-ceramic is (0.5±0.01)mm, the static compressive strength of a single bar that the chemically strengthened glass-ceramic can withstand is ≥350N, preferably 350~500N. In some embodiments, the static compressive strength of a single bar that the chemically strengthened glass-ceramic with a thickness of (0.5±0.01)mm can be 368.6N, 378.5N, 384.1N, 387.9N, 394.1N, 394.6N, 399.2N, 408.4N, or 414.6N, or can be any range and sub-range between any two specific values ​​mentioned above, as long as the chemically strengthened glass-ceramic with the performance required by this application can be obtained. It should be understood that, in specific implementation schemes, any of the above ranges can be combined with any other ranges, as long as the chemically strengthened microcrystalline glass with the desired performance of this application can be obtained.

[0201] In some embodiments of this application, a 32g steel ball is used to perform a drop ball impact test on the chemically strengthened glass-ceramic. When the thickness of the chemically strengthened glass-ceramic is (0.5±0.01) mm, the impact height of the drop ball when it breaks is ≥1.0m, preferably 1.0~1.5m. In some embodiments, when the chemically strengthened glass-ceramic with a thickness of (0.5±0.01) mm breaks, the impact height of the drop ball can be 1.0m, 1.05m, 1.1m, 1.2m, 1.3m, 1.4m, or 1.5m, or it can be any range and sub-range between any two specific values ​​mentioned above, as long as the chemically strengthened glass-ceramic with the performance required by this application can be obtained. It should be understood that in specific embodiments, any of the above ranges can be combined with any other ranges, as long as the chemically strengthened glass-ceramic with the performance required by this application can be obtained.

[0202] IV. A method for preparing chemically strengthened microcrystalline glass

[0203] In some embodiments of this application, a method for preparing the aforementioned chemically strengthened glass-ceramic is provided, the specific steps of which include: placing the aforementioned glass-ceramic in a molten salt bath at 380°C to 550°C for chemical strengthening treatment, the strengthening time being 1h to 24h.

[0204] In some embodiments of this application, the chemical enhancement treatment may employ a single-step or multi-step method, wherein the molten salt bath used in the chemical enhancement treatment is a molten salt bath containing sodium and / or potassium salts. In some embodiments, a two-step enhancement method is preferred; more preferably, in the two-step chemical enhancement treatment:

[0205] The temperature of the first-step chemical strengthening treatment is 480℃~490℃, the chemical strengthening time is 180min~240min, and the salt bath is a molten salt bath containing sodium salt, such as a pure sodium salt bath or a mixed salt bath of sodium and potassium salts. More preferably, in the salt bath of the first-step chemical strengthening treatment, the content of potassium salt is 0wt%~40wt%, the content of sodium salt is 60wt%~100wt%, and lithium salt may also be added to the salt bath, with a lithium salt content of 0.01wt%~0.3wt%.

[0206] The second step of chemical enhancement treatment is carried out at a temperature of 400℃~480℃ and for a time of 30min~180min. The salt bath is a molten salt bath containing potassium salt, such as a pure potassium salt bath or a mixed salt bath of potassium and sodium salts.

[0207] In some embodiments of this application, the sodium salt is selected from at least one of sodium nitrate, sodium sulfate, and sodium carbonate, preferably sodium nitrate; the potassium salt is selected from at least one of potassium nitrate, potassium sulfate, and potassium carbonate, preferably potassium nitrate; and the lithium salt is selected from at least one of lithium nitrate and lithium sulfate, preferably lithium nitrate.

[0208] In this application, the stress distribution structure of the chemically strengthened glass-ceramic is closely related to the composition of the glass-ceramic (including oxide composition and crystal phase composition), the composition of the salt bath, the salt bath temperature, and the chemical strengthening treatment time. Only when a glass-ceramic with a specific composition is chemically strengthened in a suitable salt bath (with suitable composition and temperature) for a suitable time can the prepared chemically strengthened glass-ceramic obtain a specific stress distribution structure, thereby achieving the excellent effect expected in this application.

[0209] V. An electronic device

[0210] In some embodiments of this application, an electronic device is provided, the electronic device comprising the above-described microcrystalline glass or the above-described chemically strengthened microcrystalline glass or the chemically strengthened microcrystalline glass prepared by the above-described preparation method.

[0211] In some embodiments, the electronic device includes a housing assembled on the outside of the electronic device, the housing comprising the aforementioned microcrystalline glass, or comprising the aforementioned chemically strengthened microcrystalline glass. The housing may be partially or entirely composed of microcrystalline glass or chemically strengthened microcrystalline glass. In some embodiments, the housing includes a display screen cover assembled on the front side of the electronic device, the display screen cover comprising the aforementioned microcrystalline glass, or comprising the aforementioned chemically strengthened microcrystalline glass. In some embodiments, the housing includes a rear cover assembled on the rear side of the electronic device, the rear cover comprising the aforementioned microcrystalline glass, or comprising the aforementioned chemically strengthened microcrystalline glass.

[0212] In some embodiments, the electronic device further includes a camera assembly, and the camera assembly is covered with a camera protective cover, which includes the aforementioned microcrystalline glass or the aforementioned chemically strengthened microcrystalline glass.

[0213] In some embodiments, the electronic device further includes a mid-frame located between the display module and the housing, the mid-frame comprising the aforementioned microcrystalline glass, or comprising the aforementioned chemically strengthened microcrystalline glass.

[0214] In some embodiments, the electronic device in this application may be one or more of the following: display screen cover, back cover, camera protective cover, and mid-frame, including the aforementioned microcrystalline glass, or including the aforementioned chemically strengthened microcrystalline glass.

[0215] The electronic devices described in this application include mobile phones, tablets, handheld game consoles, portable digital devices (such as digital cameras), vehicle central control systems, electronic whiteboard glass, smart home devices, televisions, computer displays, and smart wearable devices (such as smart bracelets, smartwatches, etc.). The high-performance microcrystalline glass provided in this application, or chemically strengthened microcrystalline glass made therefrom, can be used not only in electronic devices but also in vehicles, aircraft, or spacecraft, and in any glass device requiring microcrystalline glass. For example, it can be used for displays, cover glass, touchscreens, inner glass screens, or inner frames of electronic devices; it can be used for windshields of vehicles, aircraft, or spacecraft, such as front or side windshields; and it can be used for work surfaces, other surfaces (including but not limited to exterior wall surfaces, stair tread surfaces, column cladding, or counter surfaces), electrical doors, floor tiles, wall panels, or storage containers (including but not limited to cups, plates, medicine bottles, or beverage bottles, etc.).

[0216] VII. A type of cover glass

[0217] In some embodiments of this application, a cover glass is provided, which includes microcrystalline glass as described above, or chemically strengthened microcrystalline glass as described above. Exemplarily, the cover glass in this application can be used as a display screen cover, an electronic device back cover, or a camera protective cover.

[0218] 8. A glass product

[0219] In some embodiments of this application, a glass article is provided, comprising microcrystalline glass as described above, or chemically strengthened microcrystalline glass as described above. The glass article of this application can be used not only in electronic devices, but also in transportation vehicles, such as vehicles, aircraft, or spacecraft, and can also be used for work surfaces, other surfaces (including but not limited to exterior wall surfaces, stair tread surfaces, column cladding, or counter surfaces), appliance doors, floor tiles, wall panels, or storage containers (including but not limited to cups, plates, medicine bottles, or beverage bottles).

[0220] IX. Testing Methods

[0221] 1. Stress test:

[0222] In this application, the surface stress (such as surface CS) and potassium-sodium exchange depth (such as DOL_K) of the glass sample can be tested using a stress tester FSM-9000, and the parameters are set according to the actual refractive index of the sample, with the photoelastic coefficient fixed at 25.5 (unit: nm / cm / MPa).

[0223] In this application, the SLP-2000 stress tester can be used to test the 50μm depth stress (CS_50), compressive stress layer depth (DOL_0), and average tensile stress (|CT_AV|) of the glass sample. The parameters are set according to the actual refractive index of the sample, and the photoelastic coefficient is fixed at 25.5 (unit: nm / cm / MPa).

[0224] 2. DSC Test: After crushing the base glass, it was ground and sieved through a 200-mesh sieve. The sieve residue was collected to obtain the sample. Approximately 20 mg of the sample was then weighed and heated from room temperature to 1100 °C at a heating rate of 10 °C / min using a differential thermal analysis instrument under a nitrogen protective atmosphere to obtain the DSC test curve of the sample. The differential thermal analysis instrument used in this application was a Mettler Toledo TGA / DSC3+ thermogravimetric and simultaneous thermal analyzer. The standard used for the test was α-Al2O3 powder, and the sample was placed in a platinum crucible. The ambient temperature of the instrument was approximately 24 °C, and the air humidity was approximately ≤40%.

[0225] 3. XRD test:

[0226] The glass sample to be tested was crushed and ground into samples with a particle size of less than 75 μm. The ground sample was then tested using an X-ray diffractometer to obtain XRD diffraction peak curves and XRD diffraction data. The X-ray diffractometer used was a Shimadzu XRD-6100, with an incident angle range of 2θ = 10~50°, a scanning speed of 6° / min, an operating voltage of 40kV, and an operating current of 30mA.

[0227] Determination of crystal phase: The crystal phase in the glass sample was obtained by analyzing the XRD diffraction data using Jade software.

[0228] 4. Determination of crystallinity and content of each crystalline phase

[0229] By importing the XRD test results (RAW format) into X-ray diffraction data refinement software (such as Jade) for fitting and calculation, the crystallinity of the sample and the mass content of each crystal phase in the sample can be obtained.

[0230] 5. Determination of average grain size

[0231] Using the XRD test results, the average grain size of the sample can be calculated according to the Scherrer formula D=Kλ / (βcosθ). Here, λ is the X-ray wavelength (λ=0.154056nm), β is the full width at half maximum (FWHM) of the diffraction peak (K=0.89), and θ is the Bragg diffraction angle. Specifically, the RAW file (diffraction pattern) output from the XRD instrument is curve-fitted in Jade software. Jade outputs a fitting report. Based on the angle 2θ and Peak FWHM value (FWHM value) corresponding to each diffraction peak in the fitting report, and converting the Peak FWHM value to radians: β=(FWHM / 180×3.14), the grain size of each diffraction peak is calculated using the Scherrer formula D=Kλ / (βcosθ), and then averaged to obtain the average grain size.

[0232] 6. Thickness test

[0233] Using a micrometer with an accuracy of 0.001 mm, the thickness was measured at 5 different locations randomly selected on the sample surface, and the average value was taken as the test result.

[0234] 7. Optical performance testing

[0235] The optical properties of the samples, such as transmittance, optical b-value, and haze, were tested using a haze meter. Specifically, the transmittance, optical b-value, and haze of five pieces of glass-ceramics or chemically strengthened glass-ceramics from the same batch were measured for different wavelengths of light using a haze meter. The average transmittance at 550 nm wavelength measured from the five pieces of glass-ceramics or chemically strengthened glass-ceramics was taken as the transmittance result of the glass-ceramics or chemically strengthened glass-ceramics at 550 nm wavelength. The average optical b-value or haze measured from the five pieces of glass-ceramics or chemically strengthened glass-ceramics was taken as the optical b-value or haze result of the glass-ceramics or chemically strengthened glass-ceramics.

[0236] The haze meter used in this application test is a Konica Minolta CM-36DG spectrophotometer from Japan. The light-receiving optical system is transmission, the spectral dispersive method is a planar refracting grating, the wavelength range is 360nm~740nm, the wavelength spacing is 10nm, the illumination source is a pulsed xenon lamp X4, the ambient temperature where the instrument is placed is about 24℃, and the air humidity is about 40%.

[0237] 8. Young's modulus test

[0238] The Young's modulus of the samples was tested using the UMS-100 ultrasonic material characterization system via acoustic waves.

[0239] 9. Density test

[0240] This application uses an ALFA MIRAGE SD-200L electronic density balance from Japan to test the density of the sample. The testing principle is "Archimedes' displacement method".

[0241] 10. Drop height test of the whole machine

[0242] The average sandpaper drop resistance height refers to the sum of the sandpaper drop resistance heights measured for each of multiple identical chemically strengthened glass-ceramic samples, divided by the number of samples. This ratio characterizes the drop resistance performance of chemically strengthened glass-ceramic. At least 10 identical chemically strengthened glass-ceramic samples are tested per batch. The average sandpaper drop resistance height is:

[0243]

[0244] Where n is the number of chemically reinforced glass-ceramic samples tested in each batch, in units of pieces; hi is the drop height resistance of a single sample tested against sandpaper, in units of meters.

[0245] Specific test plan for sandpaper drop height resistance of a single sample:

[0246] Step 1: Place the glass sample to be tested, with dimensions of 50mm × 50mm × 0.5mm, onto the front of the 181g model machine;

[0247] Step 2: Place the model on the GreenMap LT-SKDL-CD drop tester, with the glass sample facing the sandpaper, and drop it from a certain height to impact the 120-grit sandpaper located directly below the model, simulating the normal mobile phone drop posture.

[0248] If the glass sample does not break, the drop height of the model machine is increased in a certain pattern. For example, starting from a drop height of 0.4m, the sample is subjected to a drop impact. If it does not break, the height is increased by 0.1m each time and the sample is dropped again until the glass sample breaks.

[0249] Step 3: Record the previous drop height when the glass sample breaks as its sandpaper drop height. For example, if the drop height is increased by 0.1m each time, and the drop height when the sample breaks is 0.5m, then the sandpaper drop height of the sample is 0.4m.

[0250] 11. Refractive index test: The refractive index of the microcrystalline glass was tested using the Abbe refractometer WYA-2WAJ of Shanghai Lichen Bangxi Instrument Technology Co., Ltd.

[0251] 12. Drop ball impact test: A 32g steel ball was used to conduct a drop ball impact test on the chemically strengthened glass-ceramic. The impact height of the drop ball when the chemically strengthened glass-ceramic broke was measured to characterize its resistance to drop ball impact.

[0252] Specifically, a chemically strengthened glass-ceramic sample with dimensions of 50mm × 50mm × 0.5mm is placed inside a fixture, and the fixture containing the sample is placed at the test position on a falling ball impact testing machine (MY-GXDL-1500). The test software is started, and the fixture position is calibrated using infrared rays. A 32g steel ball is used to perform a limit falling ball test on the center point of the chemically strengthened glass-ceramic sample. The initial impact height of the falling ball is set to 0.3m. If the sample does not break after the falling ball impacts it from the initial impact height, the impact height is increased by 0.1m each time, and the impact continues until the sample breaks.

[0253] 13. Single-bar static compressive strength test: Place the glass sample to be tested on the bottom ring of the tensile testing machine (LT-850A), start the testing software, and set the moving speed of the compression bar (bar diameter 10mm, ball head diameter 10mm) to 10mm / min. Click "Start Test." The compression bar will apply force to the center of the glass sample at the set moving speed until the glass sample cracks and breaks. The testing software will automatically read the force (N) at which the glass sample breaks and record it as the single-bar static compressive strength it can withstand, as the test result. Take 10 glass samples in the same condition for testing, and take the average value of the test results as the single-bar static compressive strength of the glass sample to be tested.

[0254] 14. Test method for the average size of the longest side of the glass fragments: First, test the average drop resistance on 120-grit sandpaper. After the glass breaks, take a picture of the breakage and import it into particle size analysis software (such as Nanomeasure) for analysis. During the analysis, select more than 80% of the glass fragments and mark them. The analysis software will automatically calculate and output the average size of the maximum size of the selected glass fragments.

[0255] 10. Examples and Comparative Examples

[0256] The embodiments of this application are described in detail below. They are exemplary and are only used to explain this application, and should not be construed as limiting this application. In the example numbers in the following tables, S refers to an embodiment, such as S1 referring to embodiment 1; D refers to a comparative example, such as D1 referring to comparative example 1.

[0257] Example 1

[0258] Prepare the raw materials according to the proportion of each oxide, with a total mass of 2000g. Add 2g of clarifying agent sodium chloride (NaCl) to the prepared raw materials, and then mix them with a V-type mixer at a speed of 25r / min for more than 30 minutes to obtain a uniformly mixed raw material mixture.

[0259] The mixed raw material mixture was transferred to a platinum crucible and melted in a platinum-rhodium crucible at 1600°C for more than 5 hours. It was then poured into a molding die and cooled to approximately 900°C. Afterward, it was annealed in a 600°C annealing furnace for 12 hours, and then cooled to room temperature in the furnace to obtain a base glass brick with dimensions of approximately 200mm × 100mm × 24mm. It should be understood that, based on the mass percentage of oxides, except for unavoidable impurities not exceeding 1% in total, the composition of the base glass obtained in each embodiment and comparative example is essentially the same as the oxide composition in Tables 1-2.

[0260] Microcrystalline glass can be prepared by sequentially nucleating and crystallizing the base glass bricks. It should be understood that, based on the mass percentage of oxides, the composition of the base glass prepared in each embodiment and comparative example is essentially the same as that of the microcrystalline glass, except for unavoidable impurities totaling no more than 1%.

[0261] To obtain the microcrystalline glass of this application, during nucleation treatment, the temperature is increased to the nucleation temperature (650℃) at a heating rate of 10℃ / min, and the holding time is 240 min. During crystallization treatment, the temperature is increased from the nucleation temperature to the crystallization temperature (750℃) at a heating rate of 10℃ / min, and the holding time is 90 min. Then, the temperature is decreased to room temperature at a cooling rate of 1℃ / min to obtain the microcrystalline glass sample brick. The nucleation holding time, or nucleation time, refers to the time spent holding the crystallization furnace at the set heating rate after reaching the set nucleation temperature. The crystallization holding time, or crystallization time, refers to the time spent holding the crystallization furnace at the set heating rate after reaching the set crystallization temperature.

[0262] After the obtained microcrystalline glass sample bricks are successively cut, CNC machined (the CNC instrument used in this application is model: RCG500S), and polished, a microcrystalline glass sample that meets the required specifications can be obtained.

[0263] The obtained glass-ceramic samples were placed in a salt bath for chemical strengthening treatment to obtain chemically strengthened glass-ceramics. It should be understood that, based on the mass percentage of oxides, except for unavoidable impurities not exceeding 1% in total, the composition of the tensile stress layer or center of the chemically strengthened glass-ceramics prepared in the embodiments and comparative examples is substantially the same as the composition of the glass-ceramics.

[0264] It should be noted that the following embodiments and comparative examples each employed their own suitable chemical strengthening processes to obtain optimal or near-optimal stress effects.

[0265] In the specific embodiments and comparative examples of this application, the microcrystalline glass sample bricks are subjected to the aforementioned cold working treatment to process them into microcrystalline glass samples that meet the requirements of different testing conditions. In this application, the main performance tests are conducted on microcrystalline glass or chemically strengthened microcrystalline glass with a thickness of approximately 0.5 mm.

[0266] The preparation processes of the base glass, microcrystalline glass, and chemically strengthened microcrystalline glass in the other embodiments and comparative examples can be referred to Example 1, except that the composition and preparation process are different. Specifically, the components, preparation processes, and performance parameters of each embodiment and comparative example are detailed in Tables 1 to 6.

[0267] Table 1 (Unit: wt%)

[0268] <![CDATA[SiO2]]> 50.08 50.14 50.83 49.52 49.23 48.84 50.51 50.51 48.31 <![CDATA[Al2O3]]> 24.87 25.78 25.32 24.52 23.71 24.13 25.03 24.96 27.33 <![CDATA[P2O5]]> 4.04 4.16 4.21 3.84 4.13 4.05 4.22 4.19 4.24 <![CDATA[ZrO2]]> 3.51 1.61 2.66 2.69 3.59 3.51 3.30 3.63 1.83 <![CDATA[Na2O]]> 11.48 11.39 10.12 11.74 12.63 12.37 11.99 10.97 12.00 <![CDATA[K2O]]> 1.34 1.37 0.00 1.37 1.37 0.00 0.28 0.94 1.40 <![CDATA[Li2O]]> 4.68 4.51 3.99 4.79 4.85 5.11 4.67 4.41 4.89 CaO 0.00 0.00 0.80 1.23 0.49 0.00 0.00 0.00 0.00 <![CDATA[B2O3]]> 0.00 1.04 2.07 0.00 0.00 1.99 0.00 0.00 0.00 ZnO 0.00 0.00 0.00 0.30 0.00 0.00 0.00 0.00 0.00 <![CDATA[Y2O3]]> 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.39 0.00 total 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00

[0269] Note: An oxide content of "0.00" in the table indicates that the component was not actively or intentionally added to the glass composition during the initial batching process, but the component may exist as an impurity.

[0270] Table 2 (Unit: wt%)

[0271] <![CDATA[SiO2]]> 49.26 48.55 47.47 49.26 43.00 46.00 48.30 43.50 48.31 48.31 49.26 49.26 <![CDATA[Al2O3]]> 27.86 27.46 26.96 27.86 21.00 25.00 22.50 32.40 27.33 27.33 27.86 27.86 <![CDATA[P2O5]]> 4.31 4.25 4.17 4.31 2.50 1.30 6.20 3.50 4.24 4.24 4.31 4.31 <![CDATA[ZrO2]]> 1.87 1.84 3.41 1.87 1.50 3.00 2.70 3.30 1.83 1.83 1.87 1.87 <![CDATA[Na2O]]> 8.47 11.13 10.93 8.47 14.00 19.30 11.30 7.80 12.00 12.00 8.47 8.47 <![CDATA[K2O]]> 1.43 1.41 1.38 1.43 1.50 0.10 0.50 1.60 1.40 1.40 1.43 1.43 <![CDATA[Li2O]]> 6.80 5.36 5.27 6.80 12.00 2.00 5.20 6.60 4.89 4.89 6.80 6.80 CaO 0.00 0.00 0.41 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 <![CDATA[B2O3]]> 0.00 0.00 0.00 0.00 4.00 3.00 1.00 0.30 0.00 0.00 0.00 0.00 ZnO 0.00 0.00 0.00 0.00 0.00 0.00 2.00 1.00 0.00 0.00 0.00 0.00 <![CDATA[Y2O3]]> 0.00 0.00 0.00 0.00 0.50 0.30 0.30 0.00 0.00 0.00 0.00 0.00 total 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00

[0272] Note: An oxide content of "0.00" in the table indicates that the component was not actively or intentionally added to the glass composition during the initial batching process, but the component may exist as an impurity.

[0273] Table 3

[0274] <![CDATA[Na2O / Li2O]]> 2.45 2.53 2.54 2.45 2.60 2.42 2.57 2.49 2.45 <![CDATA[Na2O / (P2O5×0.5)]]> 5.68 5.48 4.81 6.11 6.12 6.11 5.68 5.24 5.66 <![CDATA[Na2O / (Li2O+K2O)]]> 1.91 1.94 2.54 1.91 2.03 2.42 2.42 2.05 1.91 Nucleation temperature (°C) 650 650 650 645 645 655 655 655 650 Nucleation holding time (h) 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 Crystallization temperature (°C) 750 740 740 750 740 730 750 740 750 Crystallization holding time (h) 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 Microcrystalline glass phase Sodium nepheline, lithium nepheline Sodium nepheline, lithium nepheline Sodium nepheline, lithium nepheline Sodium nepheline, lithium nepheline Sodium nepheline, lithium nepheline Sodium nepheline, lithium nepheline Sodium nepheline, lithium nepheline Sodium nepheline, lithium nepheline Sodium nepheline, lithium nepheline Crystallinity (wt%) 75.20 72.40 68.50 76.60 77.30 75.90 73.30 68.60 78.70 Sodium nepheline content (wt%) 70.60 68.30 64.70 72.10 74.10 70.50 68.40 64.70 74.00 Nepheline content (wt%) 4.60 4.10 3.80 4.50 3.20 5.40 4.90 3.90 4.70 (Sodium nepheline content / crystallization) × 100% 93.88 94.34 94.45 94.13 95.86 92.89 93.32 94.31 94.03 (Lepidolite content / (Lepidolite content + Sodium nepheline content)) × 100% 6.12 5.66 5.55 5.87 4.14 7.11 6.68 5.69 5.97 Average grain size (nm) 29.8 25.7 24.6 26.6 29.3 27.2 25.7 24.8 28.0 Thickness (mm) 0.50 0.50 0.50 0.50 0.50 0.50 0.50 0.50 0.50 b value 0.73 0.60 0.56 0.59 0.72 0.64 0.61 0.58 0.70 Haze (%) 0.18 0.14 0.15 0.14 0.16 0.14 0.17 0.13 0.16 Transmittance at 550nm (%) 90.85 91.02 91.10 91.05 90.82 90.91 90.95 91.05 90.89 <![CDATA[Density (g / cm 3 ).]]> 2.582 2.566 2.578 2.559 2.572 2.568 2.571 2.583 2.577 Refractive index 1.536 1.534 1.537 1.535 1.536 1.534 1.538 1.542 1.539 Young's modulus (GPa) 94 92 95 93 91 92 94 99 98

[0275] Table 4

[0276] <![CDATA[Na2O / Li2O]]> 1.25 2.08 2.07 1.25 1.17 9.65 2.17 1.18 2.45 2.45 1.25 1.25 <![CDATA[Na2O / (P2O5×0.5)]]> 3.93 5.24 5.24 3.93 11.20 29.69 3.65 4.46 5.66 5.66 3.93 3.93 <![CDATA[Na2O / (Li2O+K2O)]]> 1.03 1.64 1.64 1.03 1.04 9.19 1.98 0.95 1.91 1.91 1.03 1.03 Nucleation temperature (°C) 520 520 520 520 520 520 520 520 650 650 650 650 Nucleation holding time (h) 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 Crystallization temperature (°C) 690 690 700 690 690 735 710 680 700 800 650 750 Crystallization holding time (h) 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 Microcrystalline glass phase Lithium nepheline Sodium nepheline, lithium nepheline Sodium nepheline, lithium nepheline Lithium nepheline Sodium nepheline, lithium nepheline Sodium nepheline Sodium nepheline, lithium nepheline Lithium nepheline Lithium nepheline Sodium nepheline, lithium nepheline Lithium nepheline Sodium nepheline, lithium nepheline Crystallinity (wt%) 77.30 76.80 76.10 77.30 68.20 72.40 70.70 73.10 66.20 81.20 56.30 80.60 Sodium nepheline content (wt%) 0.00 59.50 57.50 0.00 54.30 72.40 57.20 0.00 0.00 78.70 0.00 55.00 Nepheline content (wt%) 77.30 17.30 18.60 77.30 13.90 0.00 13.50 73.10 66.20 2.50 56.30 25.60 (Sodium nepheline content / crystallization) × 100% 0 77.47 75.56 0 79.62 100 80.91 0 0 96.92 0 68.24 (Lepidolite content / (Lepidolite content + Sodium nepheline content)) × 100% 100.00 22.53 24.44 100.00 20.38 0.00 19.09 100.00 100.00 3.08 100.00 31.76 Average grain size (nm) 18.60 24.30 22.40 18.60 23.6 30.1 25.7 21.1 18.2 30.5 16.5 28.9 Thickness (mm) 0.50 0.50 0.50 0.50 0.50 0.50 0.50 0.50 0.5 0.5 0.5 0.5 b value 0.36 0.45 0.52 0.36 0.51 0.4 0.48 0.37 0.39 1.20 0.35 0.98 Haze (%) 0.11 0.13 0.15 0.11 0.13 0.13 0.13 0.12 0.11 0.29 0.10 0.20 Transmittance at 550nm (%) 91.22 91.10 91.02 91.22 91.15 91.10 91.02 91.20 91.17 90.45 91.25 90.52 <![CDATA[Density (g / cm 3 )]]> 2.524 2.528 2.562 2.524 2.536 2.568 2.546 2.561 2.532 2.582 2.521 2.538 Refractive index 1.532 1.531 1.540 1.532 1.536 1.541 1.534 1.543 1.536 1.546 1.530 1.539 Young's modulus (GPa) 88 87 91 88 85 89 87 90 82 101 82 86

[0277] Table 5

[0278] Primary strengthening temperature (°C) 480 480 480 480 480 480 480 490 490 One-time enhanced salt bath formulation (wt%) <![CDATA[79.98wt%NaNO3+19.99wt%KNO3+0.03wt%LiNO3]]> <![CDATA[100wt%NaNO3]]> <![CDATA[100wt%NaNO3]]> <![CDATA[69.98wt%NaNO3+29.99wt%KNO3+0.03wt%LiNO3]]> <![CDATA[100wt%NaNO3]]> <![CDATA[100wt%NaNO3]]> <![CDATA[100wt%NaNO3]]> <![CDATA[100wt%NaNO3]]> <![CDATA[100wt%NaNO3]]> Duration of one reinforcement session (min) 200 180 180 240 180 180 210 180 210 Secondary strengthening temperature (°C) 430 430 430 430 430 430 430 430 430 Secondary enhanced salt bath formulation (wt%) <![CDATA[100%wtKNO3]]> <![CDATA[100%wtKNO3]]> <![CDATA[100%wtKNO3]]> <![CDATA[100%wtKNO3]]> <![CDATA[100%wtKNO3]]> <![CDATA[100%wtKNO3]]> <![CDATA[100%wtKNO3]]> <![CDATA[100%wtKNO3]]> <![CDATA[100%wtKNO3]]> Secondary reinforcement time (min) 120 180 120 180 120 120 120 180 180 CS_50 (MPa) 120.6 116.2 113.2 136.5 121.3 113.5 110.4 112.9 107.8 DOL_0 (μm) 106.9 110.5 111.4 109.2 107.9 110.4 108.2 109.5 111.2 DOL_0 / t 0.21 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 |CT_AV| (MPa) 88.6 87.3 80.6 85.3 89.2 86.3 84.6 84.3 79.8 CT_LD (MPa / mm) 41854.6 39983.4 36624.6 39511.0 41781.3 39559.9 39525.1 38946.6 36325.0 Surface CS (MPa) 1690.8 1586.2 1740.2 1622.6 1743.4 1699.1 1592.6 1746.4 1699.0 DOL_K(μm) 7.9 10.5 7.4 8.5 8.1 6.3 8.6 8.2 6.3 Chemically strengthened microcrystalline glass phase Sodium nepheline, lithium nepheline Sodium nepheline, lithium nepheline Sodium nepheline, lithium nepheline Sodium nepheline, lithium nepheline Sodium nepheline, lithium nepheline Sodium nepheline, lithium nepheline Sodium nepheline, lithium nepheline Sodium nepheline, lithium nepheline Sodium nepheline, lithium nepheline Crystallinity (wt%) 73.80 71.60 67.70 74.50 76.60 75.20 73.00 67.80 77.70 Sodium nepheline content (wt%) 69.60 67.50 63.80 70.20 73.20 70.00 68.10 63.80 73.20 Nepheline content (wt%) 4.20 4.10 3.90 4.30 3.40 5.20 4.90 4.00 4.50 Potassium nepheline content (wt%) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 (Lepidolite / (Lepidolite + Sodium Nepheline)) × 100% 5.69 5.73 5.76 5.77 4.44 6.91 6.71 5.90 5.79 (Sodium nepheline content / crystallization) × 100% 94.31 94.27 94.24 94.23 95.56 93.09 93.29 94.10 94.21 Drop height of 120-grit sandpaper (m) 1.10 1.05 1.00 1.05 1.10 1.15 1.02 1.05 1.00 Single rod static pressure (N) 384.1 368.6 408.4 387.9 414.6 394.6 378.5 394.1 399.2 Impact height of the ball at the center of the drop (m) 1.15 1.00 1.10 1.00 1.20 1.10 1.00 1.10 1.05 Average size of the longest side of the fragment (mm) 19 20 18 22 24 22 18 20 25

[0279] Table 6

[0280] Primary strengthening temperature (°C) 490 480 480 430 480 490 480 490 490 490 490 490 One-time enhanced salt bath formulation (wt%) <![CDATA[100wt%NaNO3]]> <![CDATA[100wt%NaNO3]]> <![CDATA[69.98wt%NaNO3+29.99wt%KNO3+0.03wt%LiNO3]]> <![CDATA[69.98wt%NaNO3+29.99wt%KNO3+0.03wt%LiNO3]]> <![CDATA[100wt%NaNO3]]> <![CDATA[100wt%NaNO3]]> <![CDATA[100wt%NaNO3]]> <![CDATA[100wt%NaNO3]]> <![CDATA[100wt%NaNO3]]> <![CDATA[100wt%NaNO3]]> <![CDATA[100wt%NaNO3]]> <![CDATA[100wt%NaNO3]]> Duration of one reinforcement session (min) 300 180 240 180 120 300 210 300 180 240 240 360 Secondary strengthening temperature (°C) 430 430 430 400 430 430 430 430 430 430 430 430 Secondary enhanced salt bath formulation (wt%) <![CDATA[100%wtKNO3]]> <![CDATA[100%wtKNO3]]> <![CDATA[100%wtKNO3]]> <![CDATA[100%wtKNO3]]> <![CDATA[100%wtKNO3]]> <![CDATA[100%wtKNO3]]> <![CDATA[100%wtKNO3]]> <![CDATA[100%wtKNO3]]> <![CDATA[100%wtKNO3]]> <![CDATA[100%wtKNO3]]> <![CDATA[100%wtKNO3]]> <![CDATA[100%wtKNO3]]> Secondary reinforcement time (min) 60 120 120 120 60 300 120 60 120 180 60.0 60.0 CS_50 (MPa) 338.9 226.8 183.5 128.6 165.8 115.5 123.9 508.6 135.6 103.6 355.2 121.6 DOL_0 (μm) 94.0 103.2 108.6 110.6 111.3 90.2 104.6 92.7 110.2 112.7 91.0 111.8 DOL_0 / t 0.19 0.21 0.22 0.22 0.22 0.18 0.21 0.19 0.22 0.23 0.18 0.22 |CT_AV| (MPa) 154.4 126.3 126.8 84.2 87.3 75.3 112.3 289.5 120.4 52.3 162.6 73.3 CT_LD (MPa / mm) 80899.4 61533.4 59038.1 38529.9 39704.0 40601.8 54083.7 153203.4 55287.7 23493.2 87153.6 33190.2 Surface CS (MPa) 1670.0 1695.3 1889.2 1760.0 1390.3 1985.6 1540.2 1391.7 1725.3 1625.4 1796.2 1483.2 DOL_K(μm) 8.0 7.5 6.8 8.2 13.2 8.6 9.2 17.7 7.9 8.9 9.5 6.2 Chemically strengthened microcrystalline glass phase Sodium nepheline, potassium nepheline Sodium nepheline, lithium nepheline, potassium nepheline Sodium nepheline, lithium nepheline, potassium nepheline Sodium nepheline, potassium nepheline Sodium nepheline, lithium nepheline, potassium nepheline Sodium nepheline Sodium nepheline, lithium nepheline, potassium nepheline Sodium nepheline, potassium nepheline Sodium nepheline, potassium nepheline Sodium nepheline, lithium nepheline Sodium nepheline, potassium nepheline Sodium nepheline, lithium nepheline, potassium nepheline Crystallinity (wt%) 48.40 55.60 52.30 56.20 49.70 70.80 51.60 30.50 46.20 78.60 41.20 77.40 Sodium nepheline content (wt%) 36.10 45.40 42.60 49.70 34.00 70.80 43.90 27.20 37.00 76.30 28.60 60.60 Nepheline content (wt%) 0.00 4.50 4.30 0.00 8.50 0.00 3.50 0.00 0.00 2.30 0.00 9.50 Potassium nepheline content (wt%) 12.30 5.70 5.40 6.50 7.20 0.00 4.20 3.30 9.20 0.00 12.60 7.30 (Lepidolite / (Lepidolite + Sodium Nepheline)) × 100% 0.00 9.02 9.17 0.00 20.00 0.00 7.38 0.00 0.00 2.93 0.00 13.55 (Sodium nepheline content / crystallization) × 100% 74.59 81.65 81.45 88.43 68.41 100 85.08 89.18 80.09 97.07 69.42 78.29 Drop height of 120-grit sandpaper (m) 0.66 0.45 0.40 0.52 0.55 0.52 0.58 1.72 0.55 0.62 0.65 0.58 Single rod static pressure (N) 313.9 327.8 302.0 315.6 299.0 452.6 305.0 228.0 376.5 416.2 365.6 319.5 Impact height of the ball at the center of the drop (m) 0.66 0.90 0.76 0.80 0.75 1.25 0.83 0.73 0.95 1.10 0.90 0.82 Average size of the longest side of the fragment (mm) 1 3 4 18 20 24 6 0.3 9 25 5 18

[0281] From Tables 1-6, we can see that:

[0282] (1) This application precisely controls the crystal phase structure of the glass-ceramic, with sodium nepheline as the main crystal phase and lithium nepheline as the secondary crystal phase, and controls the lithium nepheline content to account for 3.5% to 15% of the total content of lithium nepheline and sodium nepheline. At the same time, it optimizes the content relationship of key oxides. This not only solves the technical problems of low deep stress and poor drop resistance of glass-ceramic with a single sodium nepheline crystal phase after chemical strengthening, but also the problems of phase transformation and performance degradation of glass-ceramic with a relatively large lithium nepheline crystal phase and high crystallinity during chemical strengthening. Moreover, it enables the chemically strengthened glass-ceramic to achieve good breakage safety, is not easy to spontaneously explode, and has a large fragment size after breakage, so as not to produce a large number of small fragments. Therefore, it can effectively avoid the safety hazards caused by small fragments and can also meet the needs of temporary emergency use after breakage. It achieves the synergistic optimization of crystal phase structure stability, mechanical strength and safety, and ensures that the glass-ceramic can be chemically strengthened to produce a glass-ceramic with both high mechanical strength and good safety after chemical strengthening.

[0283] (2) From the perspective of the performance of glass-ceramics, the performance requirements of this application can be achieved by controlling the proportion of crystal phases and the composition limitation requirements in Examples S1 to S9. However, the performance requirements of this application cannot be met because the proportions are not controlled. The crystallinity of the glass-ceramics in Examples S1 to S9 is 68.50wt%~78.70wt%, the content of the sodium nepheline main crystal phase is stable at 64.70wt%~74.10wt%, and the content of the lithium nepheline secondary crystal phase is controlled at 3.20wt%~5.40wt%. The corresponding proportion of lithium nepheline in the total content of the two crystal phases is 4.14%~7.11%. At the same time, the average grain size is stable at 24.6nm~29.8nm, which does not exceed 50nm. This fully demonstrates that the composition control of this application can achieve the target crystal phase structure. In addition, the Young's modulus of the glass-ceramics prepared in these examples is ≥91GPa, and the highest is 99GPa, indicating that it has high intrinsic strength. In addition, by optimizing the composition and crystal structure, this application can ensure that the microcrystalline glass has the desired optical performance while maintaining high strength and crystal structure stability, thereby meeting the basic optical performance requirements of cover glass for electronic devices.

[0284] In the comparative examples, since the crystal structure does not meet the requirements of this application, it is impossible to ensure high intrinsic strength and excellent optical performance. For example, the Young's modulus of the microcrystalline glass prepared by comparative examples D1, D2, D4, D5, D6, D7, D8, D9, D11 and D12 is lower than 91 GPa, which is lower than the Young's modulus of the microcrystalline glass in the embodiment of this application; the b-value and haze of the microcrystalline glass of comparative example D10 are too high, and the optical performance does not meet the requirements of this application.

[0285] (3) In the chemically strengthened glass-ceramics prepared in the embodiments of this application, the crystal structure remains stable, with sodium nepheline as the main crystal phase and lithium nepheline as the secondary crystal phase. No impurity phases such as potassium nepheline are generated. The proportion of lithium nepheline in the total content of the two crystal phases remains stable at 4.44%~6.91%. The crystallinity decreases only slightly compared to before strengthening. The content of sodium nepheline and lithium nepheline changes very little, which fully demonstrates that this application improves the technical problem of poor sandpaper drop resistance in lithium-sodium nepheline glass-ceramics during chemical strengthening due to the unstable crystal structure and phase transition during the process of chemical strengthening by adjusting the ratio of sodium nepheline and lithium nepheline. Figure 3 As shown, the XRD curves of the microcrystalline glass of Example 9 of this application and the chemically strengthened microcrystalline glass made from the microcrystalline glass are basically the same. It can be seen that the crystal structure remains basically stable before and after chemical strengthening, and no obvious phase transition occurs.

[0286] In contrast, the microcrystalline glass with a high nepheline content, after chemical strengthening treatment, underwent a significant change in its crystal structure. The resulting chemically strengthened microcrystalline glass had a crystal structure that was clearly different from that of regular microcrystalline glass. Consequently, the sandpaper drop resistance of these chemically strengthened microcrystalline glasses was significantly inferior to that of the chemically strengthened microcrystalline glass in the embodiments of this application. Figure 5 , Figure 7 As shown, the XRD curves of the microcrystalline glass of Comparative Example 1 and Comparative Example 2 and the chemically strengthened microcrystalline glass prepared from them showed significant changes, indicating that the crystal phase structure changed significantly before and after chemical strengthening.

[0287] While the crystal structure of the single sodium nepheline (D6) and the low lithium nepheline (D10) was basically stable after strengthening, the low lithium or lithium nepheline content resulted in insufficient deep stress after chemical strengthening and a shallow compressive stress layer, leading to poor drop resistance of the resulting chemically strengthened microcrystalline glass.

[0288] (4) The chemically strengthened glass-ceramics prepared in the embodiments of this application meet the requirements of a suitable stress distribution structure, which provides support for good mechanical properties and breakage safety. The chemically strengthened glass-ceramics prepared in the embodiments of this application also have good drop resistance, compression resistance and impact resistance.

[0289] Comparative examples that do not meet the requirements of this application cannot simultaneously possess good drop resistance, compression resistance, and impact resistance. For example, comparative examples D1-D5, D7-D8, and D12 have low single-pole static compressive strength; comparative examples D1-D5, D7-D9, and D11-D12 have low ball impact height; and comparative examples D1-D7 and D9-D12 have low sandpaper drop resistance. Among them, although comparative example D8 appears to have high sandpaper drop resistance, its low single-pole static compressive strength and low ball impact height, and the large number of extremely fine fragments it produces after breakage, pose a significant safety hazard and cannot meet the needs of temporary emergency use after breakage.

[0290] (5) Regarding the issue of fragments after breakage, the chemically strengthened microcrystalline glass prepared according to the embodiments of this application has an average length of ≥18mm and a maximum of 25mm for the longest side of the fragments after breakage. It does not produce a large number of small fragments after breakage, effectively avoiding safety hazards caused by small fragments and meeting the needs for temporary emergency use after breakage. However, some comparative examples of chemically strengthened microcrystalline glass produce smaller and more numerous fragments after breakage, which not only easily leads to splashing and safety problems but also fails to meet the needs for emergency use. For example... Figure 10 As shown, the chemically strengthened microcrystalline glass prepared in Example 9 produced few fragments and no small fragments after breakage, while the chemically strengthened microcrystalline glass prepared in Comparative Examples 1 and 8 produced a large number of small fragments after breakage.

[0291] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and not to limit the technical solutions. Those skilled in the art should understand that any modifications or equivalent substitutions to the technical solutions of this application without departing from the spirit and scope of this technical solution should be covered within the scope of the claims of this application.

Claims

1. A microcrystalline glass, characterized in that, The microcrystalline glass comprises a primary crystalline phase, nepheline, and a secondary crystalline phase, nepheline. The mass percentage of nepheline in all crystalline phases is not less than 80%, and the mass percentage of nepheline accounts for 3.5% to 15% of the sum of the masses of nepheline and nepheline. The crystallinity of the microcrystalline glass is >60 wt%. The microcrystalline glass comprises, by mass percentage of oxides: SiO2: 47-52%, Al2O3: 23-28%, P2O5: 3.5-4.5%, ZrO2: 1.5-4%, Na2O: 10-13%, K2O: 0-2%, Li2O: 3-5.5%, CaO: 0-2%, ZnO: 0-3%, B2O3: 0-3%, and Y2O3: 0-1.5%.

2. A microcrystalline glass, characterized in that, The microcrystalline glass comprises the primary crystalline phase sodium nepheline and the secondary crystalline phase nepheline, wherein 0 < nepheline content ≤ 10 wt%, sodium nepheline content ≥ 55 wt%, the mass of nepheline accounts for 3.5% to 15% of the sum of the masses of nepheline and sodium nepheline, and the crystallinity of the microcrystalline glass is > 60 wt%.

3. The microcrystalline glass according to claim 1 or 2, characterized in that, The composition of the glass-ceramic, calculated as a percentage of oxides, satisfies the following: 2≤Na2O / Li2O≤3, preferably 2.3≤Na2O / Li2O≤2.8; 5≤Na2O / (P2O5×0.5)≤7.5, preferably, 4.5≤Na2O / (P2O5×0.5)≤6.5; 7≤Na2O / (Li2O+K2O)≤3, preferably 1.8≤Na2O / (Li2O+K2O)≤2.

7.

4. The microcrystalline glass according to claim 2, characterized in that, The composition of the glass-ceramic, based on the mass percentage of oxides, comprises: SiO2: 47~52%, Al2O3: 23~28%, P2O5: 3.5~4.5%, ZrO2: 1.5~4%, Na2O: 10~13% , K2O: 0~2%, Li2O: 3~5.5%, CaO: 0~2%, ZnO: 0~3%, B2O3: 0~3%, Y2O3: 0~1.5%.

5. The microcrystalline glass according to any one of claims 1-4, characterized in that, In the glass-ceramic, the mass of nepheline accounts for 3.5% to 10% of the sum of the masses of nepheline and sodium nepheline, preferably 3.5% to 7.5%, and more preferably 3.5% to 5%; and / or, in the glass-ceramic, the mass percentage of sodium nepheline in all crystalline phases is not less than 90%.

6. The microcrystalline glass according to claim 1, characterized in that, In the microcrystalline glass: 0 < nepheline content ≤ 10 wt%, sodium nepheline content ≥ 55 wt%.

7. The microcrystalline glass according to any one of claims 1-6, characterized in that, In the microcrystalline glass: 0 < lithium nepheline content ≤ 8wt%, 60wt% ≤ sodium nepheline content ≤ 80wt%; preferably, 3wt% ≤ lithium nepheline content ≤ 6wt%, 63wt% ≤ sodium nepheline content ≤ 75wt%.

8. The microcrystalline glass according to any one of claims 1-7, characterized in that, The crystallinity of the microcrystalline glass is 65wt%~80wt%, preferably 68wt%~78wt%; and / or, In the microcrystalline glass, the average grain size does not exceed 50 nm, preferably the average grain size is 10 nm to 40 nm, and more preferably the average grain size is 20 nm to 30 nm.

9. The microcrystalline glass according to any one of claims 1-8, characterized in that, The microcrystalline glass contains, by mass percentage of oxides: The SiO2 content is 48-51%; and / or, The Al2O3 content is 23.5%~27.5%; and / or, The P2O5 content is 3.7~4.3%; and / or, The ZrO2 content is 1.5~3.8%; and / or, The Na₂O content is 10-12.8%; and / or, The K2O content is 0~1.5%; and / or, The Li2O content is 3.5~5.2%; and / or, The CaO content is 0~1.5%; and / or, The ZnO content is 0~0.5%; and / or, The B2O3 content is 0~2.1%; and / or, The content of Y2O3 is 0~0.5%.

10. The microcrystalline glass according to any one of claims 1-9, characterized in that, When the thickness of the microcrystalline glass is 0.35mm~0.6mm, the haze of the microcrystalline glass is <0.2%, the b-value of the microcrystalline glass is <0.9, preferably b-value <0.8, more preferably b-value ≤0.75; and / or, The microcrystalline glass is transparent in the visible light wavelength range; preferably, when the thickness of the microcrystalline glass is 0.35~0.6mm, the transmittance of the microcrystalline glass at a wavelength of 550nm is ≥85%, more preferably ≥90%, and even more preferably ≥90.5%.

11. The microcrystalline glass according to any one of claims 1-10, characterized in that, The Young's modulus of the microcrystalline glass is ≥90 GPa, preferably 90 GPa~105 GPa; and / or, The refractive index of the microcrystalline glass is 1.53~1.55; and / or, The density of the microcrystalline glass is 2.5~2.7 g / cm³. 3 .

12. A chemically strengthened microcrystalline glass, characterized in that, The chemically strengthened glass-ceramic comprises a tensile stress layer and a compressive stress layer. The glass-ceramic includes a primary crystalline phase, nepheline, and a secondary crystalline phase, lepidolite. The mass percentage of nepheline in all crystalline phases is not less than 80%, and the mass percentage of lepidolite accounts for 3.5% to 15% of the sum of the masses of lepidolite and nepheline. The crystallinity of the chemically strengthened glass-ceramic is >60 wt%. The composition of the chemically strengthened glass-ceramic tensile stress layer or the composition at the center of the chemically strengthened glass-ceramic, based on the mass percentage of oxides, includes: SiO2: 47~52%, Al2O3: 23~28%, P2O5: 3.5~4.5%, ZrO2: 1.5~4%, Na2O: 10~13% , K2O: 0~2%, Li2O: 3~5.5%, CaO: 0~2%, ZnO: 0~3%, B2O3: 0~3%, Y2O3: 0~1.5%.

13. A chemically strengthened microcrystalline glass, characterized in that, The chemically strengthened glass-ceramic includes a tensile stress layer and a compressive stress layer. The chemically strengthened glass-ceramic includes a primary crystalline phase, sodium nepheline, and a secondary crystalline phase, nepheline. The nepheline content is 0 < 10 wt%, the sodium nepheline content is ≥ 55 wt%, the mass of nepheline accounts for 3.5% to 15% of the sum of the masses of nepheline and sodium nepheline, and the crystallinity of the chemically strengthened glass-ceramic is > 60 wt%.

14. The chemically strengthened microcrystalline glass according to claim 12 or 13, characterized in that, The composition of the chemically strengthened glass-ceramic tensile stress layer or the composition at the center of the chemically strengthened glass-ceramic, based on the mass percentage of oxides, satisfies the following: 2≤Na2O / Li2O≤3, preferably 2.3≤Na2O / Li2O≤2.8; 5≤Na2O / (P2O5×0.5)≤7.5, preferably 4.5≤Na2O / (P2O5×0.5)≤6.5; 7≤Na2O / (Li2O+K2O)≤3, preferably 1.8≤Na2O / (Li2O+K2O)≤2.

7.

15. The chemically strengthened glass-ceramic according to claim 13, characterized in that, The composition of the chemically strengthened glass-ceramic tensile stress layer or the composition at the center of the chemically strengthened glass-ceramic, based on the mass percentage of oxides, includes: SiO2: 47~52%, Al2O3: 23~28%, P2O5: 3.5~4.5%, ZrO2: 1.5~4%, Na2O: 10~13% , K2O: 0~2%, Li2O: 3~5.5%, CaO: 0~2%, ZnO: 0~3%, B2O3: 0~3%, Y2O3: 0~1.5%.

16. The chemically strengthened glass-ceramic according to any one of claims 12-15, characterized in that, In the chemically strengthened glass-ceramic, the mass of nepheline accounts for 3.5% to 7.3% of the sum of the masses of nepheline and sodium nepheline, preferably 4% to 7%; and / or, in the chemically strengthened glass-ceramic, the mass percentage of sodium nepheline in all crystalline phases is not less than 90%.

17. The chemically strengthened glass-ceramic according to claim 12, characterized in that, In the chemically strengthened microcrystalline glass: 0 < lithium nepheline content ≤ 10wt%, sodium nepheline content ≥ 55wt%.

18. The chemically strengthened glass-ceramic according to any one of claims 12-17, characterized in that, The chemically strengthened microcrystalline glass has a crystallinity of 65wt%~80wt%, preferably 67wt%~78wt%; and / or, In the chemically strengthened glass-ceramic, the average grain size does not exceed 50 nm, preferably 10 nm to 40 nm, and more preferably 20 nm to 30 nm; and / or, In the chemically strengthened glass-ceramic: 0 < nepheline content ≤ 8 wt%, 60 wt% ≤ sodium nepheline content ≤ 80 wt%, preferably, 3 wt% ≤ nepheline content ≤ 6 wt%, 63 wt% ≤ sodium nepheline content ≤ 75 wt%; and / or, The chemically strengthened microcrystalline glass does not contain potassium nepheline in its crystal phase.

19. The chemically strengthened glass-ceramic according to any one of claims 12-18, characterized in that, The composition of the chemically strengthened glass-ceramic tensile stress layer or the composition at the center of the chemically strengthened glass-ceramic, based on the mass percentage of oxides, is as follows: The SiO2 content is 48-51%; and / or, The Al2O3 content is 23.5%~27.5%; and / or, The P2O5 content is 3.7~4.3%; and / or, The ZrO2 content is 1.5~3.8%; and / or, The Na₂O content is 10-12.8%; and / or, The K2O content is 0~1.5%; and / or, The Li2O content is 3.5~5.2%; and / or, The CaO content is 0~1.5%; and / or, The ZnO content is 0~0.5%; and / or, The B2O3 content is 0~2.1%; and / or, The content of Y2O3 is 0~0.5%.

20. The chemically strengthened glass-ceramic according to any one of claims 12-19, characterized in that, The chemically strengthened microcrystalline glass satisfies: 20≤DOL_0 / t≤0.25, where DOL_0 is the compressive stress layer depth and t is the thickness of the chemically strengthened glass-ceramic; and / or, The surface CS is ≥1400MPa, preferably 1500MPa~1900MPa.

21. The chemically strengthened glass-ceramic according to any one of claims 12-20, characterized in that, When the thickness of the chemically strengthened glass-ceramic is (0.5±0.01) mm, the chemically strengthened glass-ceramic satisfies: The tensile stress linear density CT_LD ≥ 35000 MPa / mm, preferably CT_LD is 35000 MPa / mm ~ 50000 MPa / mm; and / or, CS_50 ≥ 100 MPa, preferably CS_50 is 100 MPa ~ 150 MPa, CS_50 refers to the compressive stress value at a depth of 50 μm from the main surface of the chemically strengthened glass-ceramic, in MPa; and / or, |CT_AV|≥75MPa, preferably |CT_AV| is 75 MPa ~100MPa, where |CT_AV| is the absolute value of the average tensile stress in MPa; and / or, DOL_K ≥ 6 μm, preferably 6 μm ~ 15 μm, where DOL_K refers to the depth of potassium ions that have penetrated into the glass through ion exchange, measured from the main surface of the chemically strengthened glass-ceramic; and / or, The compressive stress layer depth DOL_0 > 95 μm, preferably DOL_0 is 100 μm to 120 μm.

22. The chemically strengthened glass-ceramic according to any one of claims 12-21, characterized in that, The chemically strengthened microcrystalline glass was subjected to a sandpaper drop test using 120-grit sandpaper. With a thickness not exceeding 0.60 mm, preferably 0.49 mm to 0.55 mm, and more preferably 0.49 mm to 0.51 mm, the average sandpaper drop height of the chemically strengthened microcrystalline glass was ≥0.9 m, and after the glass broke upon drop, the average size of the longest side of the fragments was ≥15 mm; and / or, The chemically strengthened glass-ceramic is pressed using a 10mm diameter round-headed metal pressure bar. The static compressive strength of the single bar that the chemically strengthened glass-ceramic can withstand is tested. When the thickness does not exceed 0.60mm, preferably 0.49mm~0.55mm, and more preferably 0.49mm~0.51mm, the static compressive strength of the single bar that the chemically strengthened glass-ceramic can withstand is ≥350N, preferably 350~500N; and / or, A 32g steel ball is used to conduct a drop ball impact test on the chemically strengthened microcrystalline glass. When the thickness does not exceed 0.60mm, preferably when the thickness is 0.49mm~0.55mm, and more preferably when the thickness is 0.49mm~0.51mm, the drop ball impact height when the chemically strengthened microcrystalline glass breaks is ≥1.0m, preferably 1.0~1.5m.

23. An electronic device, characterized in that, The electronic device comprises a microcrystalline glass as claimed in any one of claims 1-11, or a chemically strengthened microcrystalline glass as claimed in any one of claims 12-22.

24. A cover glass, characterized in that, The cover glass comprises microcrystalline glass as described in any one of claims 1-11, or chemically strengthened microcrystalline glass as described in any one of claims 12-22.

25. A glass article, characterized in that, The glass article includes microcrystalline glass as described in any one of claims 1-11, or includes chemically strengthened microcrystalline glass as described in any one of claims 12-22.

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