A microcrystalline glass, a preparation method thereof, and an electronic device cover plate and an electronic device cover plate assembly made of the same

Abstract

This invention discloses a microcrystalline glass, its preparation method, and electronic device cover plates and electronic device cover plate assemblies made therefrom. The microcrystalline glass has an overall crystallinity of 60%-95%, and its crystalline phases are lithium disilicate and lithium feldspar, with a weight ratio of lithium disilicate to lithium feldspar ≥1.5. The microcrystalline glass of this invention has a specific glass composition and crystal phase structure. Utilizing the synergistic effect of its glass composition and high lithium disilicate crystal phase structure, it not only endows the microcrystalline glass products with a high elastic modulus but also enables the microcrystalline glass products to obtain the desired stress structure after chemical strengthening treatment, especially high central tensile stress (|CT-CV|) and a large average tensile stress (CT-AV).

Description

Technical Field

[0001] This invention belongs to the field of microcrystalline glass technology, specifically relating to a microcrystalline glass and its preparation method, an electronic device cover plate and an electronic device cover plate assembly, which is suitable for scenarios with high requirements for material rigidity and toughness, such as electronic device covers and precision optical devices. Background Technology

[0002] With the rapid development of consumer electronics and display technology, cover materials for electronic devices are trending towards ultra-thinness and high strength, thus placing higher demands on their mechanical properties (drop resistance) and optical properties (high transmittance, low haze). Lithium aluminum silicon (Li2O-Al2O3-SiO2, LAS) glass-ceramics have become an ideal candidate material for ultra-thin flexible display cover plates due to their excellent thermal stability, high mechanical strength, and chemically strengthenable properties. However, existing LAS glass-ceramic technologies still face challenges in achieving ultra-thinness.

[0003] WO2023246365A1 employs a low crystallinity design (approximately 20%), with lithium disilicate (Li2Si2O5) crystalline phase accounting for less than 20%. This approach has significant drawbacks: firstly, the insufficient lithium disilicate crystalline phase results in poor material hardness and scratch resistance; secondly, the excessive glass phase leads to a shallow surface compressive stress layer after chemical strengthening, and uneven distribution of central tensile stress (|CT-CV|), making the material prone to stress imbalance fracture under mechanical loads.

[0004] The Chinese patent with publication number CN116177877A designs a microcrystalline glass with lithium disilicate as the main crystalline phase and a small amount of lithium monosilicate as the crystalline phase. The lithium monosilicate crystalline phase is prone to forming coarse grains, resulting in a large upper limit of grain size (≤80nm), which affects the visible light transmittance. At the same time, coarse grains are prone to become stress concentration points, increasing the risk of brittleness.

[0005] Patent CN18307204A discloses the use of lithium disilicate / lithium feldspar (LiAlSi4O) 10 The technical scheme with a crystal ratio of 0.8-1.0 (lithium disilicate and petalite phases accounting for approximately 30-50%) exhibits a weaker crack deflection ability compared to the lithium disilicate phase, making it difficult to improve drop resistance. Furthermore, the glass strengthened in this technical scheme has a low |CT-CV| value and a high surface compressive stress (CS) value, making it prone to "stress penetration" fracture during bending.

[0006] Patent CN111099829B discloses a transparent microcrystalline glass, microcrystalline glass products, and a method for preparing the same. The main crystalline phases of the transparent microcrystalline glass contain lithium silicate and quartz phases, and its composition, expressed as a weight percentage, includes: SiO2: 65-85%; Al2O3: 1-15%; Li2O: 5-15%; ZrO2: 0.1-10%; P2O5: 0.1-10%; K2O: 0-10%; MgO: 0-10%; ZnO: 0-10%, where the (SiO2 + Li2O) / Al2O3 ratio is 6-15. However, the ion exchange layer depth of this microcrystalline glass after strengthening is relatively low, and parameters affecting the drop performance of sandpaper, such as |CT-CV|, CS-50, and CT-AV, have not been tested and characterized, making it impossible to determine whether it meets the drop resistance requirements of electronic devices. Summary of the Invention

[0007] To overcome the shortcomings of existing technologies, this invention provides a LAS microcrystalline glass that still exhibits good mechanical properties even at an ultra-thin thickness of 0.4mm-0.6mm. This invention improves the mechanical properties of the glass precursor (before strengthening) by optimizing the glass phase composition and fully utilizing the advantages of the lithium disilicate crystalline phase (the toughening mechanism of crack deflection induced by crystal structure interlocking and the intrinsic strength of the crystal). Furthermore, the glass precursor can be strengthened to further enhance its mechanical properties. The specific technical solution is as follows: The first solution provided by this invention is: a microcrystalline glass with an overall crystallinity of 60%-95%, the crystalline phases being lithium disilicate and petalite, and the weight ratio of the lithium disilicate crystalline phase to the petalite crystalline phase being ≥1.5. Controlling the overall crystallinity of the microcrystalline glass product to above 60% is fundamental to ensuring that the microcrystalline glass has good mechanical properties.

[0008] Preferably, the lithium disilicate crystalline phase accounts for 50-95 wt% of the microcrystalline glass product; more preferably, it accounts for 60-85 wt%; and even more preferably, it accounts for 60-80 wt%. The significance of the lithium disilicate crystalline phase accounting for more than 50 wt% of the microcrystalline glass product lies in the fact that it serves as a prerequisite for subsequent chemical strengthening to improve the mechanical properties of the microcrystalline glass.

[0009] Preferably, the lithium feldspar crystal phase accounts for 0.1-30 wt% of the microcrystalline glass product, more preferably 0.2-25 wt% of the microcrystalline glass product, and even more preferably 5-20 wt% of the lithium feldspar crystal phase.

[0010] The preferred mass ratio of lithium disilicate to petalite is ≥1.5, more preferably ≥2.5, and even more preferably ≥4. The mass ratio of lithium disilicate to petalite can be 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 12, 13, 14, 15, 16, 17, or 18, or any value between these two values.

[0011] Its average grain size is ≤50nm, and preferably the average grain size is 10nm-30nm.

[0012] The Young's modulus of the microcrystalline glass is greater than or equal to 90 GPa, preferably greater than or equal to 100 GPa, and more preferably greater than 110 GPa. The fact that the Young's modulus of the microcrystalline glass product is within the above range indicates that it has strong resistance to material deformation, i.e., high material stiffness, thus ensuring its excellent mechanical properties.

[0013] In this technical solution, the ROR of the microcrystalline glass is ≥1000N, preferably ≥1200N; the average failure height of the dropped ball (150g steel ball) is ≥0.4m, preferably ≥0.5m; the average failure height of the dropped 80-grit sandpaper is ≥0.3m, preferably ≥0.4m; and the average failure height of the dropped 180-grit sandpaper is ≥0.6m, preferably ≥0.8m.

[0014] The Vickers hardness of the microcrystalline glass is greater than or equal to 750 kgf / mm². 2 The preferred value is 750 kgf / mm 2 -790kgf / mm 2 .

[0015] The raw material composition of the microcrystalline glass is SiO2 60-75wt%, Al2O3 1-6wt%, Na2O 0-4wt%, K2O 0-2wt%, Li2O 12-18wt%, ZrO2 6-15wt%, P2O5 2-6wt%, CaO 0-4wt%, SnO2 0-0.1wt%, and Sb2O3 0-0.5wt%.

[0016] The mass ratio of ZrO2 / Al2O3 is 1.5-5.5, preferably 1.71 ≤ ZrO2 / Al2O3 mass ratio ≤ 5.08, and even more preferably 2.05 ≤ ZrO2 / Al2O3 mass ratio ≤ 4.45. The mass ratio of Al2O3 / Li2O is <0.45, preferably 0.05 < Al2O3 / Li2O mass ratio <0.40, and even more preferably 0.05 < Al2O3 / Li2O mass ratio <0.35.

[0017] The mass ratio of (CaO+Na2O+K2O) / Al2O3 is ≤0.39, preferably ≤0.39, and even more preferably ≤0.28.

[0018] Li2O+ZrO2-P2O5 ≥ 16.1wt%, Li2O+ZrO2-P2O5 is 16.1wt%, 16.5wt%, 17wt%, 17.5wt%, 18wt%, 18.5wt%, 19wt%, 19.5wt%, 20wt%, 20.5wt%, 21wt%, 22wt%, 22.5wt%, 23wt%, 23.5wt%, 24wt%, or 24.5wt%, or a value within the range of any two of the above specific values ​​as endpoints.

[0019] A method for preparing the aforementioned microcrystalline glass includes the following steps: Step 1: Prepare microcrystalline glass raw materials according to a certain mass ratio, mix them evenly, melt them into shape, and perform annealing treatment to obtain glass precursor; Step 2: The annealed glass precursor is subjected to crystallization heat treatment and then cooled and shaped.

[0020] The microcrystalline glass raw materials in step 1 are: SiO2 60-75wt%, Al2O3 1-6wt%, Na2O 0-4wt%, K2O 0-2wt%, Li2O 12-18wt%, ZrO2 6-15wt%, P2O5 2-6wt%, CaO 0-4wt%, SnO2 0-0.1wt%, and Sb2O3 0-0.5wt%; the melting temperature is 1400-1600℃, and the melting time is 6-10h; the preheating temperature of the stainless steel mold is 300-450℃; the annealing temperature is 400-500℃, and the annealing time is 3-6h. Preferably, the ZrO2 / Al2O3 mass ratio is 1.5-5.5, more preferably 1.71 ≤ ZrO2 / Al2O3 mass ratio ≤ 5.08, and even more preferably 2.05 ≤ ZrO2 / Al2O3 mass ratio ≤ 4.45. The mass ratio of Al2O3 / Li2O is <0.45, preferably 0.05 < Al2O3 / Li2O mass ratio <0.40, and even more preferably 0.05 < Al2O3 / Li2O mass ratio <0.35.

[0021] The mass ratio of (CaO+Na2O+K2O) / Al2O3 is ≤0.39, preferably ≤0.39, and even more preferably ≤0.28.

[0022] Li2O+ZrO2-P2O5 ≥ 16.1wt%, Li2O+ZrO2-P2O5 is 16.1wt%, 16.5wt%, 17wt%, 17.5wt%, 18wt%, 18.5wt%, 19wt%, 19.5wt%, 20wt%, 20.5wt%, 21wt%, 22wt%, 22.5wt%, 23wt%, 23.5wt%, 24wt%, or 24.5wt%, or a value within the range of any two of the above specific values ​​as endpoints.

[0023] The crystallization heat treatment in step 2 includes a nucleation stage and a crystallization stage. The temperature of the nucleation stage is 530-630℃, and the holding time is 1-10h. The temperature of the crystallization stage is 680-780℃, and the holding time is 1-10h.

[0024] An electronic device cover made of the aforementioned microcrystalline glass.

[0025] An electronic device cover assembly made of the aforementioned microcrystalline glass.

[0026] The second technical solution provided by this invention is: a high-strength, drop-resistant microcrystalline glass, which is obtained by ion strengthening treatment of the microcrystalline glass in the first solution, specifically as follows: A high-strength, drop-resistant microcrystalline glass has an overall crystallinity of 60%-95%, with lithium disilicate and petalite as the crystalline phases, and the weight ratio of the lithium disilicate crystalline phase to the petalite crystalline phase is ≥1.5. The high-strength, drop-resistant microcrystalline glass has a ROR ≥1800N, preferably ≥2000N; an average failure height of ≥1.0m from a dropped ball (150g steel ball), preferably ≥1.2m; an average failure height of ≥0.8m from a drop using 80-grit sandpaper, preferably ≥1.0m; and an average failure height of ≥1.2m from a drop using 180-grit sandpaper, preferably ≥1.5m.

[0027] Preferably, the lithium disilicate crystalline phase accounts for 50-95 wt% of the microcrystalline glass product, more preferably 60-85 wt% of the lithium disilicate crystalline phase, and even more preferably 60-80 wt% of the lithium disilicate crystalline phase.

[0028] Preferably, the lithium feldspar crystal phase accounts for 0.1-30 wt% of the microcrystalline glass product, more preferably 0.2-25 wt% of the microcrystalline glass product, and even more preferably 5-20 wt% of the lithium feldspar crystal phase.

[0029] Preferably, the mass ratio of lithium disilicate to petalite is ≥1.5; more preferably, it is ≥2.5; and even more preferably, it is ≥4. The mass ratio of lithium disilicate to petalite can be 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 12, 13, 14, 15, 16, 17, or 18, or any value between these two values.

[0030] Its average grain size is ≤50nm, and preferably the average grain size is 10nm-30nm.

[0031] When the thickness of the high-strength, drop-resistant microcrystalline glass product is 0.6 mm, the optical test wavelength range of the microcrystalline glass is 380-780 nm, the average transmittance is ≥90%, preferably ≥90.5%; the b-value is ≤0.8, preferably ≤0.6; and the haze is ≤0.3, preferably ≤0.2.

[0032] The high-strength, drop-resistant microcrystalline glass has a ROR ≥ 1800N, preferably ROR ≥ 2000N; the average failure height of a dropped ball (150g steel ball) is ≥ 1.0m, preferably ≥ 1.2m; the average failure height of 80-grit sandpaper dropped is ≥ 0.8m, preferably ≥ 1.0m; the average failure height of 180-grit sandpaper dropped is ≥ 1.2m, preferably ≥ 1.5m.

[0033] The high-strength, drop-resistant microcrystalline glass is composed of the following raw materials: SiO2 60-75wt%, Al2O3 1-6wt%, Na2O 0-4wt%, K2O 0-2wt%, Li2O 12-18wt%, ZrO2 6-15wt%, P2O5 2-6wt%, CaO 0-4wt%, SnO2 0-0.1wt%, and Sb2O3 0-0.5wt%.

[0034] The mass ratio of ZrO2 / Al2O3 is 1.5-5.5, preferably 1.71 ≤ ZrO2 / Al2O3 mass ratio ≤ 5.08, and even more preferably 2.05 ≤ ZrO2 / Al2O3 mass ratio ≤ 4.45. The mass ratio of Al2O3 / Li2O is <0.45, preferably 0.05 < Al2O3 / Li2O mass ratio <0.40, and even more preferably 0.05 < Al2O3 / Li2O mass ratio <0.35.

[0035] The mass ratio of (CaO+Na2O+K2O) / Al2O3 is ≤0.39, preferably ≤0.39, and even more preferably ≤0.28.

[0036] Li2O+ZrO2-P2O5 ≥ 16.1wt%, Li2O+ZrO2-P2O5 is 16.1wt%, 16.5wt%, 17wt%, 17.5wt%, 18wt%, 18.5wt%, 19wt%, 19.5wt%, 20wt%, 20.5wt%, 21wt%, 22wt%, 22.5wt%, 23wt%, 23.5wt%, 24wt%, or 24.5wt%, or a value within the range of any two of the above specific values ​​as endpoints.

[0037] The method for preparing high-strength, drop-resistant microcrystalline glass in this solution includes the following steps: Step 1: Prepare microcrystalline glass raw materials according to a certain mass ratio, mix them evenly, melt them into shape, and perform annealing treatment to obtain glass precursor; Step 2: The annealed glass precursor is subjected to crystallization heat treatment and then cooled and shaped. Step 3: Perform chemical strengthening treatment on the microcrystalline glass obtained in Step 2.

[0038] The microcrystalline glass raw materials in step 1 are: SiO2 60-75wt%, Al2O3 1-6wt%, Na2O 0-4wt%, K2O 0-2wt%, Li2O 12-18wt%, ZrO2 6-15wt%, P2O5 2-6wt%, CaO 0-4wt%, SnO2 0-0.1wt%, and Sb2O3 0-0.5wt%; the melting temperature is 1400-1600℃, and the melting time is 6-10h; the preheating temperature of the stainless steel mold is 300-450℃; the annealing temperature is 400-500℃, and the annealing time is 3-6h.

[0039] The crystallization heat treatment in step 2 includes a nucleation stage and a crystallization stage. The temperature of the nucleation stage is 530-630℃, and the holding time is 1-10h. The temperature of the crystallization stage is 680-780℃, and the holding time is 1-10h.

[0040] The chemical strengthening treatment in step 3 adopts a two-step strengthening process. The preferred strengthening conditions for the first step are treatment in a mixed molten salt of 40wt% NaNO3 + 60wt% KNO3 + 0.004wt%-0.03wt% LiNO3 (total of sodium nitrate and potassium nitrate) at 400-520℃ for 2-8 hours. The preferred strengthening conditions for the second step are treatment in a mixed molten salt of 30wt% NaNO3 + 70wt% KNO3 + 0.002wt%-0.01wt% LiNO3 (total of sodium nitrate and potassium nitrate) at 400-480℃ for 0.5-3 hours.

[0041] Furthermore, in step 3, the processing thickness of the microcrystalline glass is 0.4-0.6 mm.

[0042] An electronic device cover assembly made of the aforementioned microcrystalline glass.

[0043] Lithium disilicate is an orthorhombic crystal based on a [Si₂O₅] tetrahedral array, with a flat or plate-like shape. Inside the glass-ceramic, lithium disilicate crystals form a highly interlocked microstructure, causing cracks to deflect, branch, and bridge their paths, significantly hindering crack propagation. Combined with glass composition optimization, this imparts excellent intrinsic strength to the glass-ceramic precursor. Simultaneously, the refractive index of lithium disilicate is close to that of the glass matrix, making it an ideal phase for preparing highly transparent glass-ceramics.

[0044] The lithium-aluminum-silicon microcrystalline glass of the first and second technical solutions of this invention can effectively control the crystal phase formation path and ratio during the microcrystallization process by reducing the alumina content and correspondingly increasing the lithium oxide content. This compositional adjustment significantly promotes the dominant precipitation and growth of the lithium disilicate crystal phase, while significantly inhibiting the formation tendency of the lepidolite crystal phase. The mechanism of action is as follows: on the one hand, alumina, as a key component of the lepidolite crystal phase, weakens the crystallization driving force of lepidolite; on the other hand, the increase in lithium oxide content not only provides a more sufficient lithium ion source to promote the formation of the lithium disilicate crystal phase, but also reduces the viscosity of the glass melt and increases the ion mobility, which is beneficial to the formation and rapid growth of lithium disilicate crystal nuclei.

[0045] The microcrystalline glass of the present invention has a specific glass composition and crystal phase structure. By utilizing the synergistic effect of its glass composition and high lithium disilicate crystal phase structure, it not only endows the microcrystalline glass products with a high elastic modulus, but also enables the microcrystalline glass products to obtain the desired stress structure after chemical strengthening treatment, especially high central tensile stress (|CT-CV|) and large average tensile stress (CT-AV).

[0046] The improvements in |CT-CV| and CT-AV are essentially achieved by enhancing impact resistance through optimizing internal stress distribution and crack propagation behavior.

[0047] When glass is impacted (e.g., dropped), cracks typically initiate at the surface or edge and propagate inward. The presence of central tensile stress creates an "energy barrier" as the crack propagates inward, requiring it to overcome the energy gradient of the tensile stress zone (the transition from surface compressive stress to central tensile stress) during propagation. High |CT-CV| is usually accompanied by a steeper stress gradient (a faster change in stress from the surface to the center). This steep stress gradient causes the crack to deflect or bifurcate during propagation, rather than penetrating the material in a straight line. An increase in CT-AV means a higher level of tensile stress throughout the central region, requiring more energy for the crack to penetrate the entire material.

[0048] A higher CT value means a stronger internal "energy barrier" state, which can more effectively resist external forces and significantly improve the glass's bending strength and impact resistance. However, when the CT value is too high, microcracks will appear on the glass surface, and it is easy to cause spontaneous breakage.

[0049] In the second technical solution of the present invention, the high-strength, drop-resistant microcrystalline glass has a |CT-CV| ≥ 150 MPa, preferably 150 MPa ≤ |CT-CV| ≤ 230 MPa, and more preferably 150 MPa ≤ |CT-CV| ≤ 200 MPa.

[0050] The high-strength, drop-resistant microcrystalline glass has a CT-AV ≥ 105 MPa, preferably 105 MPa ≤ CT-AV ≤ 150 MPa, and more preferably 110 MPa ≤ CT-AV ≤ 140 MPa.

[0051] The high-strength, drop-resistant microcrystalline glass has a diameter of 80μm≤DOL-0≤130μm, preferably 80μm≤DOL-0≤120μm, and more preferably 90μm≤DOL-0≤120μm, where DOL-0 is the compressive stress layer depth.

[0052] The high-strength, drop-resistant microcrystalline glass has a compressive stress of 120MPa≤CS-50≤290MPa, preferably 140MPa≤CS-50≤260MPa, and more preferably 140MPa≤CS-50≤200MPa, wherein CS-50 refers to the compressive stress value at a depth of 50μm from the main surface of the chemically strengthened microcrystalline glass.

[0053] The second technical solution of this invention controls the glass phase and crystallinity (60-95%) and crystal phase composition (Li2Si2O5 content 50-95%, Li2Si2O5 / LiAlSi4O) through composition-crystallization synergy. 10The intrinsic strength and thermal stability are improved by increasing the strength to ≥1.5. Combined with chemical strengthening process, the stress structure (|CT-CV|≥150MPa, CT-AV≥105MPa) and mechanical properties are synergistically optimized to meet the stringent mechanical performance requirements of next-generation ultra-thin cover plates.

[0054] The third technical solution of the present invention is: A microcrystalline glass, the raw material composition of which is 60-75wt% SiO2, 1-6wt% Al2O3, 0-4wt% Na2O, 0-2wt% K2O, 12-18wt% Li2O, 6-15wt% ZrO2, 2-6wt% P2O5, 0-4wt% CaO, 0-0.1wt% SnO2 and 0-0.5wt% Sb2O3.

[0055] Further, the SiO2 is 62-75 wt%, preferably 62-73 wt%; Al2O3 is 1-4 wt%, preferably 2-4 wt%; Na2O is 0-3 wt%, preferably 0-2 wt%; K2O is 0-1 wt%, preferably 0-0.7 wt%; Li2O is 12-17 wt%, preferably 12-16 wt%; ZrO2 is 8-13 wt%, preferably 8-12 wt%; P2O5 is 2-5 wt%, preferably 2-4 wt%; CaO is 0-3 wt%, preferably 0-2 wt%; SnO2 is 0-0.09 wt%, preferably 0-0.08 wt%; and Sb2O3 is 0-0.45 wt%.

[0056] The mass ratio of ZrO2 / Al2O3 is 1.5-5.5, preferably 1.71 ≤ ZrO2 / Al2O3 mass ratio ≤ 5.08, and even more preferably 2.05 ≤ ZrO2 / Al2O3 mass ratio ≤ 4.45. The mass ratio of Al2O3 / Li2O is <0.45, preferably 0.05 < Al2O3 / Li2O mass ratio <0.40, and even more preferably 0.05 < Al2O3 / Li2O mass ratio <0.35.

[0057] The mass ratio of (CaO+Na2O+K2O) / Al2O3 is ≤0.39, preferably ≤0.39, and even more preferably ≤0.28.

[0058] Li2O+ZrO2-P2O5 ≥ 16.1wt%, Li2O+ZrO2-P2O5 is 16.1wt%, 16.5wt%, 17wt%, 17.5wt%, 18wt%, 18.5wt%, 19wt%, 19.5wt%, 20wt%, 20.5wt%, 21wt%, 22wt%, 22.5wt%, 23wt%, 23.5wt%, 24wt%, or 24.5wt%, or a value within the range of any two of the above specific values ​​as endpoints.

[0059] The overall crystallinity of the microcrystalline glass is 60-95%, and the crystalline phases are lithium disilicate and petalite, with a mass ratio of lithium disilicate to petalite ≥1.5. The mass ratio of lithium disilicate to petalite can be 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 12, 13, 14, 15, 16, 17, or 18, or any value between the two.

[0060] Furthermore, the average grain size of the microcrystalline glass is ≤50nm, preferably 10nm-30nm.

[0061] Furthermore, the microcrystalline glass has a Vickers hardness ≥750 kgf / mm², Young's modulus ≥90 GPa, ROR ≥1000N, average drop height ≥0.4m, average drop height ≥0.3m with 80-grit sandpaper, and average drop height ≥0.6m with 180-grit sandpaper.

[0062] Preferably, the microcrystalline glass has an ROR ≥ 1800N, an average drop height ≥ 1.0m, an average drop height ≥ 0.8m with 80-grit sandpaper, and an average drop height ≥ 1.2m with 180-grit sandpaper.

[0063] Furthermore, the microcrystalline glass has a central tensile stress |CT-CV| ≥ 150 MPa at a thickness of 0.6 mm, an average central tensile stress CT-AV ≥ 105 MPa, a compressive stress layer depth (DOL-0) of 80-130 μm, and a CS-50 of 120-290 MPa.

[0064] The preparation method of the microcrystalline glass in this scheme includes the following steps: Step 1: Prepare microcrystalline glass raw materials according to a certain mass ratio, mix them evenly, melt them into shape, and perform annealing treatment to obtain glass precursor; Step 2: The annealed glass precursor is subjected to crystallization heat treatment and then cooled and shaped.

[0065] The microcrystalline glass raw materials in step 1 are SiO2 60-75wt%, Al2O3 1-6wt%, Na2O 0-4wt%, K2O 0-2wt%, Li2O 12-18wt%, ZrO2 6-15wt%, P2O5 2-6wt%, CaO 0-4wt%, SnO2 0-0.1wt%, and Sb2O3 0-0.5wt%; the melting process is as follows: melting temperature is 1400-1600℃, and melting time is 6-10h.

[0066] The crystallization heat treatment in step 2 includes a nucleation stage and a crystallization stage. The temperature of the nucleation stage is 530-630℃, and the holding time is 1-10h. The temperature of the crystallization stage is 680-780℃, and the holding time is 1-10h.

[0067] Preferably, the process further includes step 3, chemically strengthening the microcrystalline glass obtained in step 2.

[0068] Furthermore, the chemical strengthening treatment in step 3 adopts a two-step strengthening process. The preferred strengthening conditions for the first step are treatment in a mixed molten salt of 40wt% NaNO3 + 60wt% KNO3 + 0.004wt%-0.03wt% LiNO3 (the total amount of sodium nitrate and potassium nitrate) at 400-520℃ for 2-8 hours. The preferred strengthening conditions for the second step are treatment in a mixed molten salt of 30wt% NaNO3 + 70wt% KNO3 + 0.002wt%-0.01wt% LiNO3 (the total amount of sodium nitrate and potassium nitrate) at 400-480℃ for 0.5-3 hours.

[0069] An electronic device cover made of the aforementioned microcrystalline glass.

[0070] An electronic device cover assembly made of the aforementioned microcrystalline glass.

[0071] Composition descriptions of the microcrystalline glass in the three technical solutions: SiO2 (silicon dioxide) is the main form of the glass network, and its content directly affects the melting characteristics, viscosity, and mechanical strength of the glass. A suitable SiO2 content can maintain a stable glass network structure, enhance resistance to crack propagation, and thus improve drop resistance. However, if the SiO2 content is too high, the melting temperature rises, affecting glass forming; if it is too low, the network structure becomes loose, reducing the hardness and impact resistance of the glass. In this invention, the SiO2 content is 60-75 wt%, preferably 62-75 wt%, and more preferably 62-73 wt%. In some embodiments of this invention, it may contain 60 wt%, 61 wt%, 62 wt%, 63 wt%, 64 wt%, 65 wt%, 66 wt%, 67 wt%, 68 wt%, 69 wt%, 70 wt%, 71 wt%, 72 wt%, 73 wt%, 74 wt%, or 75 wt%, or any value between these two values ​​of SiO2.

[0072] Al₂O₃ (alumina), as a network intermediate, can partially replace SiO₂ in the network structure, filling network voids. It can also combine with Li₂O and SiO₂ to form a lithium feldspar crystal phase, improving the mechanical strength and scratch resistance of the glass. Too low an Al₂O₃ content hinders crystal precipitation and makes it difficult to increase the glass phase modulus, thus reducing its impact resistance. Too high an Al₂O₃ content leads to severe crystallization, affecting the optical and mechanical properties of the glass material. In this invention, the Al₂O₃ content is 1-6 wt%, preferably 1-4 wt%, and more preferably 2-4 wt%. In some embodiments of this invention, it may contain approximately 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, or 6 wt%, or any value between any two of these values ​​for Al₂O₃.

[0073] Furthermore, by controlling the Al2O3 / Li2O ratio within a specific range, this invention can achieve a directional increase in the proportion of lithium disilicate crystalline phase and effective suppression of the lithopone crystalline phase in the microstructure, thereby optimizing the mechanical strength of the glass-ceramic. In this invention, the Al2O3 / Li2O mass ratio is <0.45, more preferably 0.05 < Al2O3 / Li2O mass ratio <0.40, and even more preferably 0.05 < Al2O3 / Li2O mass ratio <0.35.

[0074] P2O5 (phosphorus pentoxide) can promote uniform nucleation, refine grain size, and combine with Li2O to form Li3PO4, assisting in the directional growth of lithium aluminum silicate crystals. If P2O5 is too low, it cannot provide sufficient nucleation sites, causing the glass system to tend to precipitate a lithium silicate crystal, which is not the target crystalline phase. If P2O5 is too high, the precipitated grains will be too large, affecting light transmittance. Therefore, the P2O5 content in this invention is 2-6 wt%, preferably 2-5 wt%, and more preferably 2-4 wt%. In some embodiments of this invention, it may contain 2 wt%, 3 wt%, 4 wt%, 5 wt%, or 6 wt%, or any value between any two of these values ​​for P2O5.

[0075] CaO (calcium oxide), as a network modifier, can break the Si-O-Si network, increase the density of non-bridging oxygen, and lower the melting temperature. It can also modulate ion exchange channels; a small amount of Ca... 2+ It can partially occupy the migration channels of alkali metal ions, affecting the exchange rate and optimizing the stress structure. If the CaO content is too high, Ca... 2+ High CaO content can clog diffusion channels and impose stricter requirements on ion exchange conditions. Furthermore, high CaO content can easily lead to glass crystallization, affecting optical performance. Therefore, the CaO content in this invention is 0-4 wt%, preferably 0-3 wt%, and more preferably 0-2 wt%. In some embodiments of this invention, the content may include 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, or 4 wt%, or any value between any two of these values ​​for CaO.

[0076] ZrO2 (zirconia) is a highly efficient nucleating agent that optimizes crystal size and distribution, thereby improving the mechanical properties of materials. Simultaneously, ZrO2 strengthens the glass network structure, enabling materials to withstand greater internal tensile stress without fracturing, thus raising the upper limit of the CT value. 4+ZrO2 tends to accumulate in grain boundary regions, increasing the elastic modulus of the glass phase while inhibiting abnormal grain growth. Too low a ZrO2 content affects crystallization uniformity, leading to large grain size differences and localized stress concentration. Too high a ZrO2 content causes a sharp increase in glass melt viscosity, making it difficult to remove bubbles and affecting product yield. It also easily leads to excessive crystallization and low transmittance. In this invention, the ZrO2 content is 6-15 wt%, preferably 8-13 wt%, and more preferably 8-12 wt%. In some embodiments of the present invention, ZrO2 may be included in the composition at 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, or 12 wt%, or any value between any two of these values. Simultaneously, the present invention controls the ZrO2 / Al2O3 mass ratio to be 1.50 ≤ ZrO2 / Al2O3 ≤ 5.52, more preferably 1.71 ≤ ZrO2 / Al2O3 ≤ 5.08, and even more preferably 2.05 ≤ ZrO2 / Al2O3 ≤ 4.45. By controlling the relative content of ZrO2 and Al2O3, the rigidity, density, and bonding strength of the glass network are enhanced, while maximizing the nucleation and growth of lithium disilicate, making it the main crystalline phase and obtaining an ideal fine-grained structure. Furthermore, increasing the relative content of ZrO2 in the glass phase composition (relative to Al2O3) can effectively enhance the central tensile stress level of the chemically strengthened glass-ceramic.

[0077] Li₂O (lithium oxide) is a key component in the formation of the network modifier and the main crystalline phase. An appropriate amount of Li₂O ensures the formation of a high proportion of lithium disilicate crystalline phase during heat treatment, increasing the crystal's elastic modulus and improving hardness and scratch resistance. However, excessive Li₂O can lead to glass devitrification and reduced light transmittance; insufficient Li₂O results in insufficient crystallization, affecting the strengthening effect. Therefore, the Li₂O content in this invention is 12-18 wt%, preferably 12-17 wt%, and more preferably 12-16 wt%. In some embodiments of this invention, it may contain 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, or 18 wt%, or any value between any two of these values.

[0078] Li₂O is an essential component of the main crystalline phases (lithium disilicate and petalite). ZrO₂ is a highly efficient nucleating agent, and the precipitation of lithium disilicate requires the synergistic effect of "free" Li₂O. P₂O₅ is an auxiliary nucleating agent, promoting the fixation of Li₂O by petalite and lithium phosphate, thus reducing its fluidity. Li₂O is the resource, P₂O₅ is the consumer, and ZrO₂ is the enhancer. Li₂O + ZrO₂ – P₂O₅ > 16.1 wt%, meaning that after deducting the fixation of Li₂O by P₂O₅, the sum of the nucleation contributions of the remaining Li₂O and ZrO₂ is still sufficient to ensure that the precipitation of lithium disilicate reaches the target crystalline phase.

[0079] Sodium oxide (Na₂O) acts as a network modifier, effectively lowering the melting temperature. It is also a core component for chemical fortification, primarily providing exchangeable sodium. + In molten salt with K + Displacement occurs, regulating the high central tensile stress. Excessive Na₂O content increases the coefficient of thermal expansion of the glass, thus reducing its thermal stability. Therefore, the upper limit of Na₂O content in this invention is set at 4 wt%, preferably 0-3 wt%, and more preferably 0-2 wt%. In some embodiments of this invention, Na₂O may be contained in approximately 0.1 wt%, 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, or 4 wt%, or any value between any two of these values.

[0080] Potassium oxide (K2O) acts as a flux, lowering the melting temperature and crystallization tendency of glass. However, as a network modifier, its network-breaking effect can reduce the mechanical strength, thermal stability, and weather resistance of the glass; therefore, its content should not be too high. Thus, the K2O content in this invention is 0-2%, preferably 0-1 wt%, and more preferably 0-0.7 wt%. In some embodiments of this invention, it may contain approximately 0.05 wt%, 0.1 wt%, 0.2 wt%, 0.5 wt%, 0.8 wt%, or 1 wt%, or any value between any two of these values ​​for K2O.

[0081] The present invention controls the mass ratio of (CaO+Na2O+K2O) / Al2O3 to ≤0.45, more preferably (CaO+Na2O+K2O) / Al2O3 to ≤0.39, and even more preferably (CaO+Na2O+K2O) / Al2O3 to ≤0.28. This can adjust the viscosity of the glass system, improve the ion migration rate and crystallization rate, and facilitate the rapid precipitation of the target crystalline phase.

[0082] SnO2 (tin oxide) and Sb2O3 (antimony oxide) are used as clarifying agents and have a significant impact on the melting quality of glass. SnO2 and Sb2O3 can reduce or eliminate small bubbles in the melt, improving the clarity and uniformity of the glass; their combined effect is even better. However, excessive addition of SnO2 and Sb2O3 increases the risk of glass devitrification, affecting product quality. Therefore, the upper limit of SnO2 content in this invention is set at 0.1 wt%, preferably 0-0.09 wt%, and more preferably 0-0.08 wt%. In some embodiments of this invention, 0%, 0.02 wt%, 0.03 wt%, 0.05 wt%, 0.08 wt%, 0.09 wt%, and 0.1 wt% SnO2 may be included. The upper limit of Sb2O3 content in this invention is set at 0.5 wt%, preferably 0-0.5 wt%, and more preferably 0-0.45 wt%. In some embodiments of the present invention, 0% to 0.05 wt%, 0.1 wt%, 0.17 wt%, 0.26 wt%, 0.34 wt%, and 0.46 wt% of Sb2O3 may be included.

[0083] The beneficial effects of this invention are: 1. By controlling the glass composition, crystallinity and phase ratio of lithium aluminum silicon microcrystalline glass, and by combining a two-step chemical strengthening process, the synergistic balance and enhancement of the material's mechanical and optical properties are achieved: stress structure optimization: after strengthening, |CT-CV|≥150MPa, CT-AV≥105MPa, effectively inhibiting crack propagation; 2. Excellent mechanical properties: Before strengthening: Vickers hardness ≥ 750 kgf / mm 2 Young's modulus ≥ 90 GPa, ROR ≥ 1000 N, average drop height of ball ≥ 0.4 m, average drop height of 80 grit sandpaper ≥ 0.3 m, average drop height of 180 grit sandpaper ≥ 0.6 m; After strengthening: Vickers hardness ≥ 780 kgf / mm 2 ROR ≥ 1800N, average drop height of ball ≥ 1.0m, average drop height of 80-grit sandpaper ≥ 0.8m, average drop height of 180-grit sandpaper ≥ 1.2m; 3. High light transmittance: Average transmittance ≥90% in the 380-780nm wavelength range, b-value ≤0.8, haze ≤0.3, meeting the requirements of high-end electronic cover plates. Attached Figure Description

[0084] Figure 1 These are XRD curves of the microcrystalline glass prepared in Examples 2, 7, Comparative Example 1, and Comparative Example 2 of the present invention; Figure 2 These are images of the morphology of the microcrystalline glass obtained in Examples 2, 7, Comparative Example 1, and Comparative Example 2 of the present invention. Figure 3 The transmittance curves of the microcrystalline glass prepared in Examples 2, 7, Comparative Example 1 and Comparative Example 2 of the present invention are shown. Figure 4 This is a diagram showing the fracture state of the chemically strengthened microcrystalline glass prepared in Example 2 of the present invention after a drop test. Detailed Implementation

[0085] The various specific technical features described above in this invention can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this invention will not describe the various possible combinations separately.

[0086] Unless otherwise specified, the numerical range described in this invention includes all values ​​within this range, and also includes any range of values ​​formed by any two values ​​within this range. For example, 6-15% includes all values ​​between 6 and 15%, and also includes any number of values ​​within this range (e.g., 6.8%, 9.6%, 12.8%) and the range of values ​​they may form (e.g., 6-12%, 8-15%, 9-11%).

[0087] Preparation of impact-resistant microcrystalline glass substrate: Weigh the raw materials according to the raw material composition of Examples 1-18 and Comparative Examples 1-16 in Tables 1-1 and 1-2, mix them evenly, melt them in a platinum crucible at 1500°C for 6 hours, pour them into a stainless steel mold preheated to 380°C, and anneal them at 480°C for 5 hours.

[0088] Table 1-1 Raw material composition of Examples 1-14 and Comparative Examples 1-9

[0089] Table 1-2 Raw material composition of Examples 15-18 and Comparative Examples 10-16

[0090] Example 1

[0091] This embodiment provides a shock-resistant microcrystalline glass product, which is obtained by melting the following components by mass percentage: SiO2 69.08%, Al2O3 4.73%, CaO 0.27%, Na2O 0.70%, ZrO2 7.20%, Li2O 13.20%, K2O 0.11%, P2O5 4.30%, SnO2 0.04%, and Sb2O3 0.37%, wherein the mass ratio of ZrO2 / Al2O3 is 1.52, and the mass ratio of (CaO+Na2O+K2O) / Al2O3 is 0.23.

[0092] The glass substrate obtained above was then subjected to nucleation (580℃×4h) and crystallization (720℃×1h) treatments to prepare a microcrystalline glass containing lithium disilicate and petalite crystalline phases. The crystallinity of this microcrystalline glass was 78%, the mass percentage of the lithium disilicate crystalline phase was 53%, the mass percentage of the petalite crystalline phase was 25%, and the ratio of lithium disilicate to petalite was 2.12. The average transmittance of this microcrystalline glass with a thickness of 0.6 mm in the 380-780 nm wavelength range was 91.65%, the b-value was 0.31, and the haze was 0.09.

[0093] Before strengthening, the 0.6 mm thick microcrystalline glass had a Vickers hardness of 778 kgf / mm², a Young's modulus of 98 GPa, a ROR of 1096 N, an average failure height of 0.5 m from a 150g falling ball, a failure height of 0.72 m from a 180-grit sandpaper drop, and a failure height of 0.36 m from an 80-grit sandpaper drop. Strengthening process: First, ion exchange at 500℃ for 4 h in a 40wt% NaNO₃ + 60wt% KNO₃ + 0.1wt% LiNO₃ salt bath; second, ion exchange at 460℃ for 1 h in a 30% NaNO₃ + 70% KNO₃ + 0.05wt% LiNO₃ salt bath. The measured stresses were: DOL-0 107.511 μm, |CT-CV| 160.601 MPa, CS-50 132.311 MPa, and CT-AV 113.771 MPa.

[0094] Performance test results after reinforcement: Vickers hardness 836 kgf / mm², ROR 1896 N, drop ball failure height 0.80 m, 80-grit sandpaper failure height 0.92 m, 180-grit sandpaper failure height 1.32 m.

[0095] Example 2

[0096] This embodiment provides a shock-resistant microcrystalline glass product, which is obtained by melting the following components by mass percentage: SiO2 68.56%, Al2O3 3.63%, CaO 0.46%, Na2O 0.30%, ZrO2 9.50%, Li2O 14.00%, P2O5 3.20%, SnO2 0.05%, and Sb2O3 0.30%, wherein the mass ratio of ZrO2 / Al2O3 is 2.62, and the mass ratio of (CaO+Na2O+K2O) / Al2O3 is 0.21.

[0097] The glass substrate obtained above was then subjected to nucleation (570℃×5h) and crystallization (730℃×2h) treatments to obtain a microcrystalline glass containing lithium disilicate and lithium feldspar crystal phases.

[0098] At a thickness of 0.6 mm, the unstrengthened microcrystalline glass in this embodiment exhibits the following characteristics: Vickers hardness 795 kgf / mm², Young's modulus 125 GPa, ROR 1563 N, average failure height from a 150g falling ball (1.02 m), failure height from a 180-grit sandpaper drop (1.12 m), and failure height from an 80-grit sandpaper drop (0.84 m). The strengthening process is the same as in Example 1. The measured stresses are: DOL-0 111.125 μm, |CT-CV| 180.106 MPa, CS-50 165.054 MPa, and CT-AV 131.026 MPa.

[0099] Performance test results after reinforcement: Vickers hardness 816 kgf / mm², ROR 2460 N, drop ball failure height 1.62 m, 80-grit sandpaper failure height 1.58 m, 180-grit sandpaper failure height 1.96 m. Figure 1 and Figure 2 The XRD and SEM images of the product obtained in this embodiment are given respectively. Figure 1 It can be seen that the crystalline phases of the microcrystalline glass prepared in this embodiment are lithium disilicate and petalite. The crystallinity of the microcrystalline glass is calculated to be 86%, with lithium disilicate accounting for 69% of the crystalline phase by mass and petalite accounting for 17% by mass. The ratio of lithium disilicate to petalite is 4.06. Figure 2 As can be seen, the average grain size of the microcrystalline glass prepared in this embodiment is 20 nm; Figure 3 The transmittance test results of the microcrystalline glass prepared in this embodiment are shown in the figure. The average transmittance of the microcrystalline glass in the 380-780nm band is 91.71%, the b-value is 0.25, and the haze is 0.06. Figure 4 This is the state of breakage after a drop test according to the embodiment. Figure 4 It is evident that the microcrystalline glass prepared in this embodiment exhibits good fracture characteristics, effectively controlling the risk of spontaneous explosion due to high stress, thus ensuring safety.

[0100] Example 3

[0101] This embodiment provides a shock-resistant microcrystalline glass product, which is obtained by melting the following components by mass percentage: SiO2 67.51%, Al2O3 4.72%, CaO 0.97%, Na2O 0.23%, ZrO2 8.94%, Li2O 12.96%, K2O 0.63%, P2O5 3.59%, SnO2 0.04%, and Sb2O3 0.41%, wherein the mass ratio of ZrO2 / Al2O3 is 1.89, and the mass ratio of (CaO+Na2O+K2O) / Al2O3 is 0.39.

[0102] The obtained glass substrate was then subjected to nucleation (580℃×4h) and crystallization (720℃×1.5h) treatments to prepare a microcrystalline glass containing lithium disilicate and petalite crystalline phases. The crystallinity of this microcrystalline glass was 82%, the mass percentage of the lithium disilicate crystalline phase was 57%, the mass percentage of the petalite crystalline phase was 25%, and the ratio of lithium disilicate to petalite was 2.28. The average transmittance of the microcrystalline glass in the 380-780nm wavelength range was 91.53%, the b-value was 0.43, and the haze was 0.10.

[0103] At a thickness of 0.6 mm, the unstrengthened microcrystalline glass in this embodiment exhibits a Vickers hardness of 781 kgf / mm², a Young's modulus of 95 GPa, a ROR of 1036 N, an average failure height of 0.56 m from a 150g falling ball, a failure height of 0.75 m from a 180-grit sandpaper drop, and a failure height of 0.38 m from an 80-grit sandpaper drop. The strengthening process is the same as in Example 1. The measured stresses are: DOL-0 = 111.822 μm, |CT-CV| = 165.786 MPa, CS-50 = 152.573 MPa, and CT-AV = 116.297 MPa.

[0104] Performance test results after reinforcement: Vickers hardness 809 kgf / mm², ROR 2004 N, drop ball failure height 1.12 m, 80-grit sandpaper failure height 1.08 m, 180-grit sandpaper failure height 1.34 m.

[0105] Example 4

[0106] This embodiment provides a shock-resistant microcrystalline glass product, which is obtained by melting the following components by mass percentage: SiO2 66.67%, Al2O3 3.77%, CaO 1.09%, ZrO2 12.00%, Li2O 13.46%, K2O 0.09%, P2O5 2.47%, SnO2 0.07%, and Sb2O3 0.38%, wherein the mass ratio of ZrO2 / Al2O3 is 3.19, and the mass ratio of (CaO+Na2O+K2O) / Al2O3 is 0.31.

[0107] The glass substrate obtained above was then subjected to nucleation (600℃×3h) and crystallization (740℃×1h) treatments to prepare a microcrystalline glass containing lithium disilicate and petalite crystalline phases. The crystallinity of this microcrystalline glass was 80%, the mass percentage of the lithium disilicate crystalline phase was 60%, the mass percentage of the petalite crystalline phase was 20%, and the ratio of lithium disilicate to petalite was 3.00. The average transmittance of the microcrystalline glass in the 380-780nm wavelength range was 91.56%, the b-value was 0.47, and the haze was 0.09.

[0108] At a thickness of 0.6 mm, the unstrengthened microcrystalline glass in this embodiment exhibits the following characteristics: Vickers hardness 786 kgf / mm², Young's modulus 109 GPa, ROR 1263 N, average failure height from a 150g falling ball (0.72 m), failure height from a 180-grit sandpaper drop (0.84 m), and failure height from an 80-grit sandpaper drop (0.50 m). The strengthening process is the same as in Example 1. The measured stresses are: DOL-0 94.068 μm, |CT-CV| 196.008 MPa, CS-50 143.476 MPa, and CT-AV 133.584 MPa.

[0109] Performance test results after reinforcement: Vickers hardness 800 kgf / mm², ROR 2169 N, drop ball failure height 1.36 m, 80-grit sandpaper failure height 1.26 m, 180-grit sandpaper failure height 1.65 m.

[0110] Example 5

[0111] This embodiment provides a shock-resistant microcrystalline glass product, which is obtained by melting the following components by mass percentage: SiO2 70.41%, Al2O3 3.83%, Na2O 1.03%, ZrO2 6.83%, Li2O 14.36%, K2O 0.26%, P2O5 2.88%, SnO2 0.07%, and Sb2O3 0.29%, wherein the mass ratio of ZrO2 / Al2O3 is 1.78 and the mass ratio of (CaO+Na2O+K2O) / Al2O3 is 0.35.

[0112] The glass substrate obtained above was then subjected to nucleation (560℃×4h) and crystallization (730℃×1h) treatments to prepare a microcrystalline glass containing lithium disilicate and petalite crystalline phases. The crystallinity of this microcrystalline glass was 81%, the mass percentage of the lithium disilicate crystalline phase was 60%, the mass percentage of the petalite crystalline phase was 21%, and the ratio of lithium disilicate to petalite was 2.86. The average transmittance of the microcrystalline glass in the 380-780nm wavelength range was 91.67%, the b-value was 0.38, and the haze was 0.08.

[0113] At a thickness of 0.6 mm, the unstrengthened microcrystalline glass in this embodiment exhibits the following characteristics: Vickers hardness 783 kgf / mm², Young's modulus 105 GPa, ROR 1345 N, average failure height from a 150g falling ball (0.64 m), failure height from a 180-grit sandpaper drop (0.88 m), and failure height from an 80-grit sandpaper drop (0.52 m). The strengthening process is the same as in Example 1. The measured stresses are: DOL-0 98.659 μm, |CT-CV| 163.411 MPa, CS-50 125.714 MPa, and CT-AV 114.369 MPa.

[0114] Performance test results after reinforcement: Vickers hardness 810 kgf / mm², ROR 2054 N, drop ball failure height 1.28 m, 80-grit sandpaper failure height 1.20 m, 180-grit sandpaper failure height 1.58 m.

[0115] Example 6

[0116] This embodiment provides a shock-resistant microcrystalline glass product, which is obtained by melting the following components by mass percentage: SiO2 70.23%, Al2O3 1.75%, ZrO2 8.83%, Li2O 16.16%, P2O5 2.42%, SnO2 0.08%, Sb2O3 0.22%, and K2O 0.31%, wherein the mass ratio of ZrO2 / Al2O3 is 5.05 and the mass ratio of (CaO+Na2O+K2O) / Al2O3 is 0.18.

[0117] The obtained glass substrate was then subjected to nucleation (570℃×4h) and crystallization (740℃×1h) treatments to prepare a microcrystalline glass containing lithium disilicate and petalite crystalline phases. The crystallinity of this microcrystalline glass was 93%, the mass percentage of the lithium disilicate crystalline phase was 73%, the mass percentage of the petalite crystalline phase was 20%, and the ratio of lithium disilicate to petalite was 3.65. The average transmittance of the microcrystalline glass in the 380-780nm wavelength range was 91.66%, the b-value was 0.23, and the haze was 0.06.

[0118] At a thickness of 0.6 mm, the unstrengthened microcrystalline glass in this embodiment exhibits the following characteristics: Vickers hardness 792 kgf / mm², Young's modulus 115 GPa, ROR 1452 N, average failure height of a 150g falling ball (0.70 m), failure height from a 180-grit sandpaper drop (0.92 m), and failure height from an 80-grit sandpaper drop (0.60 m). The strengthening process is the same as in Example 1. The measured stresses are: DOL-0 106.631 μm, |CT-CV| 203.065 MPa, CS-50 174.538 MPa, and CT-AV 138.239 MPa.

[0119] Performance test results after reinforcement: Vickers hardness 799 kgf / mm², ROR 2335 N, drop ball failure height 1.40 m, 80-grit sandpaper failure height 1.24 m, 180-grit sandpaper failure height 1.72 m.

[0120] Example 7

[0121] This embodiment provides a shock-resistant microcrystalline glass product, which is obtained by melting the following components by mass percentage: SiO2 72.52%, Al2O3 1.43%, ZrO2 6.00%, Li2O 17.10%, P2O5 2.00%, SnO2 0.06%, Sb2O3 0.35%, and K2O 0.54%, wherein the mass ratio of ZrO2 / Al2O3 is 4.20 and the mass ratio of (CaO+Na2O+K2O) / Al2O3 is 0.38.

[0122] The glass substrate obtained above was then subjected to nucleation (590℃×3h) and crystallization (750℃×1h) treatments to obtain a microcrystalline glass containing lithium disilicate and lithium feldspar crystal phases.

[0123] Figure 1 and Figure 2 The XRD and SEM images of the product obtained in this embodiment are given respectively. Figure 1 It can be seen that the crystalline phases of the microcrystalline glass prepared in this embodiment are lithium disilicate and petalite. The crystallinity of the microcrystalline glass is calculated to be 76%, with lithium disilicate accounting for 64% of the crystalline phase by mass and petalite accounting for 12% by mass. The ratio of lithium disilicate to petalite is 5.33. Figure 2 As can be seen, the average grain size of the microcrystalline glass prepared in this embodiment is 20 nm; Figure 3 The transmittance test results of the microcrystalline glass prepared in this embodiment are shown in the figure. The average transmittance of the microcrystalline glass in the 380-780nm band is 91.45%, the b-value is 0.32, and the haze is 0.13.

[0124] At a thickness of 0.6 mm, the unstrengthened microcrystalline glass in this embodiment exhibits the following characteristics: Vickers hardness 784 kgf / mm², Young's modulus 132 GPa, ROR 1505 N, average failure height from a 150g falling ball (1.08 m), failure height from a 180-grit sandpaper drop (1.12 m), and failure height from an 80-grit sandpaper drop (0.86 m). The strengthening process is the same as in Example 1. The measured stresses are: DOL-0 106.623 μm, |CT-CV| 196.411 MPa, CS-50 166.294 MPa, and CT-AV 136.926 MPa.

[0125] Performance test results after reinforcement: Vickers hardness 798 kgf / mm², ROR 2586 N, drop ball failure height 1.69 m, 80-grit sandpaper failure height 1.55 m, 180-grit sandpaper failure height 2.02 m.

[0126] Example 8

[0127] This embodiment provides a shock-resistant microcrystalline glass product, which is obtained by melting the following components by mass percentage: SiO2 69.09%, Al2O3 3.30%, Na2O 0.78%, ZrO2 9.07%, Li2O 14.47%, P2O5 2.80%, SnO2 0.07%, and Sb2O3 0.42%, wherein the mass ratio of ZrO2 / Al2O3 is 2.75, and the mass ratio of (CaO+Na2O+K2O) / Al2O3 is 0.24.

[0128] The glass substrate obtained above was then subjected to nucleation (585℃×4h) and crystallization (730℃×2h) treatments to prepare a microcrystalline glass containing lithium disilicate and petalite crystalline phases. The crystallinity of this microcrystalline glass was 91%, the mass percentage of the lithium disilicate crystalline phase was 68%, the mass percentage of the petalite crystalline phase was 23%, and the ratio of lithium disilicate to petalite was 2.96. The average transmittance of the microcrystalline glass in the 380-780nm wavelength range was 91.18%, the b-value was 0.36, and the haze was 0.11.

[0129] At a thickness of 0.6 mm, the unstrengthened microcrystalline glass in this embodiment exhibits the following characteristics: Vickers hardness 777 kgf / mm², Young's modulus 112 GPa, ROR 1380 N, average failure height from a 150g falling ball (0.82 m), failure height from a 180-grit sandpaper drop (0.96 m), and failure height from an 80-grit sandpaper drop (0.58 m). The strengthening process is the same as in Example 1. The measured stresses are: DOL-0 112.194 μm, |CT-CV| 184.778 MPa, CS-50 187.581 MPa, and CT-AV 123.300 MPa.

[0130] Performance test results after reinforcement: Vickers hardness 794 kgf / mm², ROR 2351 N, drop ball failure height 1.26 m, 80-grit sandpaper failure height 1.28 m, 180-grit sandpaper failure height 1.65 m.

[0131] Example 9

[0132] This embodiment provides a shock-resistant microcrystalline glass product, which is obtained by melting the following components by mass percentage: SiO2 69.05%, Al2O3 1.95%, CaO 0.20%, ZrO2 10.34%, Li2O 15.67%, P2O5 2.22%, SnO2 0.05%, Sb2O3 0.19%, and K2O 0.33%, wherein the mass ratio of ZrO2 / Al2O3 is 5.30, and the mass ratio of (CaO+Na2O+K2O) / Al2O3 is 0.27.

[0133] The glass substrate obtained above was then subjected to nucleation (560℃×5h) and crystallization (745℃×1h) treatments to prepare a microcrystalline glass containing lithium disilicate and petalite crystalline phases. The crystallinity of this microcrystalline glass was 85%, the mass percentage of the lithium disilicate crystalline phase was 70%, the mass percentage of the petalite crystalline phase was 15%, and the ratio of lithium disilicate to petalite was 4.67. The average transmittance of the microcrystalline glass in the 380-780nm wavelength range was 91.27%, the b-value was 0.27, and the haze was 0.10.

[0134] At a thickness of 0.6 mm, the unstrengthened microcrystalline glass in this embodiment exhibits the following characteristics: Vickers hardness 768 kgf / mm², Young's modulus 130 GPa, ROR 1668 N, average failure height from a 150g falling ball (1.18 m), failure height from a 180-grit sandpaper drop (1.09 m), and failure height from an 80-grit sandpaper drop (0.79 m). The strengthening process is the same as in Example 1. The measured stresses are: DOL-0 107.641 μm, |CT-CV| 217.186 MPa, CS-50 199.773 MPa, and CT-AV 142.394 MPa.

[0135] Performance test results after reinforcement: Vickers hardness 807 kgf / mm², ROR 2450 N, drop ball failure height 1.58 m, 80-grit sandpaper failure height 1.58 m, 180-grit sandpaper failure height 1.86 m.

[0136] Example 10

[0137] This embodiment provides a shock-resistant microcrystalline glass product, which is obtained by melting the following components by mass percentage: SiO2 67.62%, Al2O3 4.32%, CaO 0.77%, ZrO2 9.56%, Li2O 13.19%, P2O5 4.06%, SnO2 0.06%, Sb2O3 0.25%, and K2O 0.17%, wherein the mass ratio of ZrO2 / Al2O3 is 2.21 and the mass ratio of (CaO+Na2O+K2O) / Al2O3 is 0.22.

[0138] The obtained glass substrate was then subjected to nucleation (575℃×4h) and crystallization (720℃×3h) treatments to prepare a microcrystalline glass containing lithium disilicate and petalite crystalline phases. The crystallinity of this microcrystalline glass was 80%, the mass percentage of the lithium disilicate crystalline phase was 57%, the mass percentage of the petalite crystalline phase was 23%, and the ratio of lithium disilicate to petalite was 2.48. The average transmittance of the microcrystalline glass in the 380-780nm wavelength range was 91.15%, the b-value was 0.41, and the haze was 0.09.

[0139] At a thickness of 0.6 mm, the unstrengthened microcrystalline glass in this embodiment exhibits the following characteristics: Vickers hardness 785 kgf / mm², Young's modulus 96 GPa, ROR 1260 N, average failure height from a 150g falling ball (0.56 m), failure height from a 180-grit sandpaper drop (0.75 m), and failure height from an 80-grit sandpaper drop (0.36 m). The strengthening process is the same as in Example 1. The measured stresses are: DOL-0 105.801 μm, |CT-CV| 170.526 MPa, CS-50 154.938 MPa, and CT-AV 119.977 MPa.

[0140] Performance test results after reinforcement: Vickers hardness 810 kgf / mm², ROR 2053 N, drop ball failure height 1.14 m, 80-grit sandpaper failure height 1.12 m, 180-grit sandpaper failure height 1.40 m.

[0141] Example 11

[0142] This embodiment provides a shock-resistant microcrystalline glass product, which is obtained by melting the following components by mass percentage: SiO2 65.75%, Al2O3 4.36%, Na2O 0.32%, ZrO2 12.14%, Li2O 12.67%, P2O5 3.72%, SnO2 0.07%, and Sb2O3 0.33%, wherein the mass ratio of ZrO2 / Al2O3 is 2.78, and the mass ratio of (CaO+Na2O+K2O) / Al2O3 is 0.22.

[0143] The glass substrate obtained above was then subjected to nucleation (605℃×3h) and crystallization (740℃×1h) treatments to prepare a microcrystalline glass containing lithium disilicate and petalite crystalline phases. The crystallinity of this microcrystalline glass was 79%, the mass percentage of the lithium disilicate crystalline phase was 52%, the mass percentage of the petalite crystalline phase was 27%, and the ratio of lithium disilicate to petalite was 1.93. The average transmittance of the microcrystalline glass in the 380-780nm wavelength range was 91.03%, the b-value was 0.32, and the haze was 0.08.

[0144] At a thickness of 0.6 mm, the unstrengthened microcrystalline glass in this embodiment exhibits the following characteristics: Vickers hardness 788 kgf / mm², Young's modulus 92 GPa, ROR 1052 N, average failure height of a 150g falling ball (0.45 m), failure height from a 180-grit sandpaper drop (0.62 m), and failure height from an 80-grit sandpaper drop (0.40 m). The strengthening process is the same as in Example 1. The measured stresses are: DOL-0 112.007 μm, |CT-CV| 184.106 MPa, CS-50 190.795 MPa, and CT-AV 127.557 MPa.

[0145] Performance test results after reinforcement: Vickers hardness 801 kgf / mm², ROR 1854 N, drop ball failure height 1.02 m, 80-grit sandpaper failure height 1.04 m, 180-grit sandpaper failure height 1.32 m.

[0146] Example 12

[0147] This embodiment provides a shock-resistant microcrystalline glass product, which is obtained by melting the following components by mass percentage: SiO2 66.42%, Al2O3 3.66%, CaO 0.11%, ZrO2 11.04%, Li2O 13.47%, P2O5 4.82%, SnO2 0.07%, Sb2O3 0.36%, and K2O 0.05%, wherein the mass ratio of ZrO2 / Al2O3 is 3.02 and the mass ratio of (CaO+Na2O+K2O) / Al2O3 is 0.04.

[0148] The glass substrate obtained above was then subjected to nucleation (580℃×3h) and crystallization (750℃×1h) treatments to prepare a microcrystalline glass containing lithium disilicate and petalite crystalline phases. The crystallinity of this microcrystalline glass was 80%, the mass percentage of the lithium disilicate crystalline phase was 60%, the mass percentage of the petalite crystalline phase was 20%, and the ratio of lithium disilicate to petalite was 3.00. The average transmittance of the microcrystalline glass in the 380-780nm wavelength range was 91.32%, the b-value was 0.31, and the haze was 0.10.

[0149] At a thickness of 0.6 mm, the unstrengthened microcrystalline glass in this embodiment exhibits the following characteristics: Vickers hardness 769 kgf / mm², Young's modulus 108 GPa, ROR 1425 N, average failure height from a 150g falling ball (0.68 m), failure height from a 180-grit sandpaper drop (0.96 m), and failure height from an 80-grit sandpaper drop (0.55 m). The strengthening process is the same as in Example 1. The measured stresses are: DOL-0 109.379 μm, |CT-CV| 189.597 MPa, CS-50 182.956 MPa, and CT-AV 132.001 MPa.

[0150] Performance test results after reinforcement: Vickers hardness 795 kgf / mm², ROR 2210 N, drop ball failure height 1.25 m, 80-grit sandpaper failure height 1.24 m, 180-grit sandpaper failure height 1.54 m.

[0151] Example 13

[0152] This embodiment provides a shock-resistant microcrystalline glass product, which is obtained by melting the following components by mass percentage: SiO2 64.78%, Al2O3 3.12%, CaO 0.28%, Na2O 0.12%, ZrO2 14.17%, Li2O 13.57%, P2O5 3.36%, SnO2 0.08%, Sb2O3 0.37%, and K2O 0.15%, wherein the mass ratio of ZrO2 / Al2O3 is 4.54, and the mass ratio of (CaO+Na2O+K2O) / Al2O3 is 0.18.

[0153] The glass substrate obtained above was then subjected to nucleation (575℃×3h) and crystallization (725℃×2h) treatments to prepare a microcrystalline glass containing lithium disilicate and petalite crystalline phases. The crystallinity of this microcrystalline glass was 85%, the mass percentage of the lithium disilicate crystalline phase was 64%, the mass percentage of the petalite crystalline phase was 21%, and the ratio of lithium disilicate to petalite was 3.05. The average transmittance of the microcrystalline glass in the 380-780nm wavelength range was 90.70%, the b-value was 0.51, and the haze was 0.12.

[0154] At a thickness of 0.6 mm, the unstrengthened microcrystalline glass in this embodiment exhibits the following characteristics: Vickers hardness 784 kgf / mm², Young's modulus 110 GPa, ROR 1306 N, average failure height from a 150g falling ball (0.68 m), failure height from a 180-grit sandpaper drop (0.96 m), and failure height from an 80-grit sandpaper drop (0.58 m). The strengthening process is the same as in Example 1. The measured stresses are: DOL-0 108.857 μm, |CT-CV| 197.413 MPa, CS-50 187.870 MPa, and CT-AV 138.086 MPa.

[0155] Performance test results after reinforcement: Vickers hardness 813 kgf / mm², ROR 2309 N, drop ball failure height 1.35 m, 80-grit sandpaper failure height 1.21 m, 180-grit sandpaper failure height 1.70 m.

[0156] Example 14

[0157] This embodiment provides a shock-resistant microcrystalline glass product, which is obtained by melting the following components by mass percentage: SiO2 68.71%, Al2O3 2.34%, ZrO2 10.77%, Li2O 13.57%, P2O5 4.24%, SnO2 0.05%, and Sb2O3 0.32%, wherein the mass ratio of ZrO2 / Al2O3 is 4.60 and the mass ratio of (CaO+Na2O+K2O) / Al2O3 is 0.

[0158] The obtained glass substrate was then subjected to nucleation (580℃×3h) and crystallization (720℃×1.5h) treatments to prepare a microcrystalline glass containing lithium disilicate and petalite crystalline phases. The crystallinity of this microcrystalline glass was 82%, the mass percentage of the lithium disilicate crystalline phase was 68%, the mass percentage of the petalite crystalline phase was 14%, and the ratio of lithium disilicate to petalite was 4.86. The average transmittance of the microcrystalline glass in the 380-780nm wavelength range was 91.13%, the b-value was 0.36, and the haze was 0.07.

[0159] The performance data of the microcrystalline glass in this embodiment before strengthening at a thickness of 0.6 mm are shown in Table 2-3. Chemical strengthening was then performed using the same strengthening process as in Example 1, and the performance test results after strengthening are shown in Table 2-3.

[0160] The raw material composition, preparation process, and performance of the final products obtained in Examples 15-18 and Comparative Examples 10-14 are shown in Tables 1-2, 2-5, and 2-6, respectively.

[0161] Comparative Example 1 This comparative example provides a microcrystalline glass product, which, by mass percentage, is obtained by melting the following components: SiO2 69.18%, Al2O3 6.48%, CaO 1.70%, Na2O 0.57%, ZrO2 5.80%, Li2O 11.80%, K2O 0.73%, P2O5 3.42%, SnO2 0.05%, and Sb2O3 0.27%, wherein the mass ratio of ZrO2 / Al2O3 is 0.90, and the mass ratio of (CaO+Na2O+K2O) / Al2O3 is 0.46.

[0162] The glass substrate obtained above was then subjected to nucleation (590℃×4h) and crystallization (740℃×1h) treatments to obtain a microcrystalline glass containing lithium disilicate and lithium feldspar crystal phases. Figure 1 and Figure 2 The XRD and SEM images of the product obtained in this comparative example are given respectively. Figure 1 It can be seen that the crystalline phases of the microcrystalline glass prepared in this comparative example are lithium disilicate and petalite. The crystallinity of this microcrystalline glass is calculated to be 88%, with lithium disilicate accounting for 44% of the crystalline phase by mass and petalite accounting for 44% of the crystalline phase by mass. The ratio of lithium disilicate to petalite is 1.00. Figure 2 It can be seen that the average grain size of the microcrystalline glass prepared in this comparative example is 20 nm; Figure 3 The transmittance test results of the microcrystalline glass prepared in this comparative example are shown in the figure. The average transmittance of the microcrystalline glass in the 380-780nm band is 90.81%, the b-value is 0.61, and the haze is 0.10.

[0163] At a thickness of 0.6 mm, the unstrengthened microcrystalline glass in this comparative example exhibited the following characteristics: Vickers hardness 801 kgf / mm², Young's modulus 88 GPa, ROR 1045 N, average failure height from a 150g falling ball (0.32 m), failure height from a 180-grit sandpaper drop (0.50 m), and failure height from an 80-grit sandpaper drop (0.24 m). The strengthening process was the same as in Example 1. The measured stresses were: DOL-0 106.525 μm, |CT-CV| 118.097 MPa, CS-50 101.831 MPa, and CT-AV 81.505 MPa.

[0164] Performance test results after reinforcement: Vickers hardness 836 kgf / mm², ROR 1639 N, drop ball failure height 0.92 m, 80-grit sandpaper failure height 0.75 m, 180-grit sandpaper failure height 1.15 m.

[0165] Comparative Example 2 This comparative example provides a microcrystalline glass product, which, by mass percentage, is obtained by melting the following components: SiO2 67.79%, Al2O3 5.95%, CaO 0.41%, Na2O 1.23%, ZrO2 7.50%, Li2O 11.87%, K2O 0.42%, P2O5 4.42%, SnO2 0.06%, and Sb2O3 0.35%, wherein the mass ratio of ZrO2 / Al2O3 is 1.26, and the mass ratio of (CaO+Na2O+K2O) / Al2O3 is 0.35.

[0166] The glass substrate obtained above was then subjected to nucleation (580℃×4h) and crystallization (740℃×1h) treatments to obtain a microcrystalline glass containing lithium disilicate and lithium feldspar crystal phases. Figure 1 and Figure 2 The XRD and SEM images of the product obtained in this comparative example are given respectively. Figure 1 It can be seen that the crystalline phases of the microcrystalline glass prepared in this comparative example are lithium disilicate and petalite. The crystallinity of this microcrystalline glass is calculated to be 91%, with lithium disilicate accounting for 46% of the crystalline phase by mass and petalite accounting for 45% by mass. The ratio of lithium disilicate to petalite is 1.00. Figure 2 As can be seen, the average grain size of the microcrystalline glass prepared in this embodiment is 20 nm; Figure 3 The transmittance test results of the microcrystalline glass prepared in this embodiment are shown in the figure. The average transmittance of the microcrystalline glass in the 380-780nm band is 91.01%, the b-value is 0.52, and the haze is 0.15.

[0167] At a thickness of 0.6 mm, the microcrystalline glass in this comparative example exhibits the following characteristics: Vickers hardness 810 kgf / mm², Young's modulus 86 GPa, ROR 1106 N, average failure height after a 150g falling ball test of 0.40 m, failure height after a drop with 180-grit sandpaper of 0.52 m, and failure height after a drop with 80-grit sandpaper of 0.20 m. The strengthening process is the same as in Example 1. The measured stresses are: DOL-0 115.867 μm, |CT-CV| 140.117 MPa, CS-50 141.713 MPa, and CT-AV 99.625 MPa.

[0168] Performance test results after reinforcement: Vickers hardness 838 kgf / mm², ROR 1705 N, drop ball failure height 0.84 m, 80-grit sandpaper failure height 0.70 m, 180-grit sandpaper failure height 1.20 m.

[0169] Comparative Example 3 This comparative example provides a microcrystalline glass product, which, by mass percentage, is obtained by melting the following components: SiO2 68.15%, Al2O3 8.56%, Na2O 0.41%, ZrO2 6.74%, Li2O 12.34%, K2O 0.89%, P2O5 2.46%, SnO2 0.04%, and Sb2O3 0.41%, wherein the mass ratio of ZrO2 / Al2O3 is 0.79, and the mass ratio of (CaO+Na2O+K2O) / Al2O3 is 0.15.

[0170] The glass substrate obtained above was then subjected to nucleation (580℃×4h) and crystallization (720℃×1h) treatments to prepare a microcrystalline glass containing lithium disilicate and petalite crystalline phases. The crystallinity of this microcrystalline glass was 85%, the mass percentage of the lithium disilicate crystalline phase was 40%, the mass percentage of the petalite crystalline phase was 45%, and the ratio of lithium disilicate to petalite was 0.88. The average transmittance of the microcrystalline glass in the 380-780nm wavelength range was 90.73%, the b-value was 0.65, and the haze was 0.14.

[0171] At a thickness of 0.6 mm, the microcrystalline glass in this comparative example exhibits the following characteristics: Vickers hardness 796 kgf / mm², Young's modulus 90 GPa, ROR 1158 N, average failure height after a 150g drop ball test of 0.40 m, failure height after a drop with 180-grit sandpaper of 0.60 m, and failure height after a drop with 80-grit sandpaper of 0.24 m. The strengthening process is the same as in Example 1. The measured stresses are: DOL-0 101.281 μm, |CT-CV| 124.941 MPa, CS-50 109.897 MPa, and CT-AV 84.981 MPa.

[0172] Performance test results after reinforcement: Vickers hardness 843 kgf / mm², ROR 1815 N, drop ball failure height 0.86 m, 80-grit sandpaper failure height 0.80 m, 180-grit sandpaper failure height 1.24 m.

[0173] Comparative Example 4 This comparative example provides a microcrystalline glass product, which, by mass percentage, is obtained by melting the following components: SiO2 70.69%, Al2O3 7.18%, CaO 0.88%, Na2O 0.61%, ZrO2 5.71%, Li2O 11.45%, K2O 0.32%, P2O5 2.79%, SnO2 0.08%, and Sb2O3 0.29%, wherein the mass ratio of ZrO2 / Al2O3 is 0.80, and the mass ratio of (CaO+Na2O+K2O) / Al2O3 is 0.25.

[0174] The glass substrate obtained above was then subjected to nucleation (575℃×4h) and crystallization (730℃×1h) treatments to prepare a microcrystalline glass containing lithium disilicate and petalite crystalline phases. The crystallinity of this microcrystalline glass was 93%, the mass percentage of the lithium disilicate crystalline phase was 50%, the mass percentage of the petalite crystalline phase was 43%, and the ratio of lithium disilicate to petalite was 1.16. The average transmittance of the microcrystalline glass in the 380-780nm wavelength range was 90.68%, the b-value was 0.75, and the haze was 0.14.

[0175] At a thickness of 0.6 mm, the microcrystalline glass in this comparative example exhibits the following characteristics: Vickers hardness 820 kgf / mm², Young's modulus 92 GPa, ROR 904 N, average failure height after a 150g drop ball test of 0.36 m, failure height after a drop with 180-grit sandpaper of 0.50 m, and failure height after a drop with 80-grit sandpaper of 0.30 m. The strengthening process is the same as in Example 1. The measured stresses are: DOL-0 106.803 μm, |CT-CV| 126.414 MPa, CS-50 121.962 MPa, and CT-AV 96.333 MPa.

[0176] Performance test results after reinforcement: Vickers hardness 851 kgf / mm², ROR 1675 N, drop ball failure height 0.84 m, 80-grit sandpaper failure height 0.68 m, 180-grit sandpaper failure height 1.30 m.

[0177] Comparative Example 5 This comparative example provides a microcrystalline glass product, which, by mass percentage, is obtained by melting the following components: SiO2 72.40%, Al2O3 6.73%, CaO 0.56%, Na2O 0.80%, ZrO2 5.50%, Li2O 11.17%, K2O 0.26%, P2O5 2.23%, SnO2 0.05%, and Sb2O3 0.30%, wherein the mass ratio of ZrO2 / Al2O3 is 0.82, and the mass ratio of (CaO+Na2O+K2O) / Al2O3 is 0.24.

[0178] The glass substrate obtained above was then subjected to nucleation (570℃×5h) and crystallization (730℃×2h) treatments to prepare a microcrystalline glass containing lithium disilicate and petalite crystalline phases. The crystallinity of this microcrystalline glass was 91%, the mass percentage of the lithium disilicate crystalline phase was 47%, the mass percentage of the petalite crystalline phase was 44%, and the ratio of lithium disilicate to petalite was 1.07. The average transmittance of the microcrystalline glass in the 380-780nm wavelength range was 90.49%, the b-value was 0.72, and the haze was 0.13.

[0179] At a thickness of 0.6 mm, the microcrystalline glass in this comparative example exhibits the following characteristics: Vickers hardness 805 kgf / mm², Young's modulus 95 GPa, ROR 1087 N, average failure height after a 150g falling ball test of 0.40 m, failure height after a drop with 180-grit sandpaper of 0.50 m, and failure height after a drop with 80-grit sandpaper of 0.28 m. The strengthening process is the same as in Example 1. The measured stresses are: DOL-0 115.286 μm, |CT-CV| 130.888 MPa, CS-50 134.104 MPa, and CT-AV 94.533 MPa.

[0180] Performance test results after reinforcement: Vickers hardness 830 kgf / mm², ROR 1934 N, drop ball failure height 0.90 m, 80-grit sandpaper failure height 0.75 m, 180-grit sandpaper failure height 1.10 m.

[0181] The microcrystalline glass prepared in Examples 1-18 and Comparative Examples 1-16 were subjected to the following tests: The test methods are as follows: Vickers hardness: Used to assess a material's resistance to localized plastic deformation. During the test, a diamond pyramidal indenter (136° angle) is perpendicularly pressed into a polished glass surface with a standard test force, held for 15 seconds, and then unloaded. The Vickers hardness value is calculated using the formula: Vickers hardness value = constant × test force / indentation surface area = 0.1891 × F / d 2 Calculate the hardness value.

[0182] Young's modulus: A measure of the stiffness of a glass material within its elastic deformation range; a higher value indicates greater stiffness and resistance to deformation. This invention employs the UMS-100 ultrasonic material characterization system to test the Young's modulus of microcrystalline glass using acoustic waves.

[0183] Average transmittance, b-value and haze: The present invention uses a high-precision spectrophotometer HAM-300 to measure the average transmittance, b-value and haze at wavelengths of 380-780nm, and the test is carried out according to GB / T 2410 standard.

[0184] Crystal phase: The crystal phase of the glass-ceramic was confirmed by XRD testing. The testing method was as follows: the glass-ceramic product was crushed and ground into powder. The powdered sample was then tested using an X-ray diffractometer to obtain the XRD diffraction peak curve and XRD diffraction data. The X-ray diffractometer used in this application was the Rigaku Ultima IV from Japan, with a testing range of 2θ from 10° to 35° and a scanning speed of 10° / min. Finally, the XRD diffraction data was analyzed using Jade software to determine the crystal phase in the glass sample.

[0185] Crystallinity and Crystalline Phase Mass Ratio: XRD patterns were analyzed using Jade software. First, the XRD pattern was decomposed by full-spectrum fitting or manual fitting to separate the envelopes of crystalline diffraction peaks and diffuse amorphous "humps." Crystallinity was calculated using the formula: Crystallinity = (Crystalline peak area / Total peak area) × 100%. Subsequently, a multiphase model was constructed including all crystalline phases (lithium disilicate, lepidolite, and other possible crystalline phases) and amorphous phases. Parameters such as background function, peak shape function, lattice parameters, peak width, and shift were then set. Finally, the Rietveld refinement method was used to fit and optimize the full spectrum, refining the parameters until convergence (Rwp < 10%). After refinement, the software automatically calculated and output the mass fraction of all phases, including the amorphous phase, based on the proportion factor, cell parameters, and chemical formula weight of each phase, thus directly obtaining the mass ratio of lithium disilicate and lepidolite in the sample.

[0186] Grain size: The grain size was determined by scanning electron microscopy (SEM). The surface of the glass-ceramic was treated with 10% HF acid, and the sample was prepared and then scanned under an SEM.

[0187] Stress testing: Stress was measured using a SLP-2000 glass surface stress meter. The |CT_CV|, CT_AV, CS_50, and DOL_0 of the chemically strengthened microcrystalline glass were tested.

[0188] ROR: Place a 150×60×0.5mm glass plate on the center of a large support ring (40mm in diameter), and apply pressure to the central area at a constant rate of 10mm / min through a small loading ring (8mm in diameter) until the glass sample breaks. Record the maximum fracture load force.

[0189] Drop Ball Test: This invention uses a drop ball tester to test the impact resistance of microcrystalline glass. Specifically, the microcrystalline glass sample is placed on a mold, and a 150g steel ball is dropped from a specified height. The maximum drop height from which the sample can withstand the impact without breaking is measured. More specifically, the test is conducted starting from a height of 30cm, with the center point dropped, and each subsequent drop increasing by 10cm until the microcrystalline glass breaks. At least 5 glass samples are taken from each batch for testing.

[0190] 80 / 180 grit sandpaper drop test: The average drop height resisted by sandpaper tested in this invention is used to characterize the drop damage resistance of chemically strengthened glass-ceramics. A drop tester is used to perform a surface drop test on glass samples using 80 / 180 grit silicon carbide sandpaper. The model machine impacts the glass samples from a certain drop height, starting at 50 cm and increasing in increments of 10 cm, with one drop at each height until the glass breaks. The breakage height is recorded.

[0191] When testing the microcrystalline glass in Examples 1-18 and Comparative Examples 1-16, the thickness of the microcrystalline glass was uniformly 0.6 mm. The test results are shown in Tables 2-1, 2-2, 2-3, 2-4, 2-5, and 2-6. Table 2-1 Relevant process parameters and performance test results of the microcrystalline glass prepared in Examples 1-6

[0192] Table 2-2 Relevant process parameters and performance test results of the microcrystalline glass prepared in Examples 7-12

[0193] Table 2-3 Relevant process parameters and performance test results of the microcrystalline glass prepared in Examples 13-14 and Comparative Examples 1-4

[0194] Table 2-4 Relevant process parameters and performance test results of the microcrystalline glass prepared in Comparative Examples 5-9

[0195] Table 2-5 Relevant process parameters and performance test results of the microcrystalline glass prepared in Examples 15-18

[0196] Table 2-6 Relevant process parameters and performance test results of the microcrystalline glass prepared in Comparative Examples 10-16

[0197] As can be seen from Tables 2-1, 2-2, 2-3, 2-4, 2-5, and 2-6, the microcrystalline glass prepared by the method of the present invention also has good performance before strengthening, and its performance is further improved after strengthening. Compared with the microcrystalline glass prepared in the comparative example, it has a significant improvement and advantage in performance. The key difference between the microcrystalline glass in the examples and the microcrystalline glass in the comparative example lies in the proportion of lithium disilicate crystal phase and the mass ratio of lithium disilicate crystal phase to lithium feldspar crystal phase.

[0198] In addition, the applicant also tested the impact resistance of the microcrystalline glass prepared in Examples 1-4 and Comparative Examples 1-2 at different thicknesses and before and after strengthening. The test results are shown in Table 3.

[0199] Table 3 shows the impact resistance of the microcrystalline glass prepared in Examples 1-4 and Comparative Examples 1-2 at different thicknesses, before and after strengthening.

[0200] Table 4. Impact resistance of the microcrystalline glass prepared in Examples 15-18 and Comparative Examples 12-14 at different thicknesses and before and after strengthening.

[0201] As shown in Tables 3 and 4, the microcrystalline glass products prepared in the embodiments of the present invention have better drop resistance when the thickness is 0.4 mm after strengthening than some comparative examples when the thickness is 0.6 mm after strengthening, which provides the possibility for further ultra-thinning of the corresponding product terminals.

[0202] Table 5 provides the raw material composition, preparation process, and composition and properties of the microcrystalline glass obtained in Examples 19-24.

[0203] Table 5

[0204] Table 6 provides the raw material composition, preparation process, and composition and properties of the microcrystalline glass obtained in Examples 25-30.

[0205] Table 6

[0206] Table 7 provides the raw material composition, preparation process, and composition and properties of the microcrystalline glass obtained in Examples 31-37.

[0207] Table 7

[0208] As can be further seen from Examples 19-37, microcrystalline glass with excellent mechanical and optical properties can be obtained in all embodiments that meet the technical requirements of the present invention.

Claims

1. A microcrystalline glass, characterized in that, Its overall crystallinity is 60%-95%, and the crystalline phases are lithium disilicate and petalite. The weight ratio of lithium disilicate to petalite is ≥1.

5. The raw material composition of this microcrystalline glass is 60-75wt% SiO2, 1-6wt% Al2O3, 0-4wt% Na2O, 0-2wt% K2O, 12-18wt% Li2O, 6-15wt% ZrO2, 2-6wt% P2O5, 0-4wt% CaO, 0-0.1wt% SnO2 and 0-0.5wt% Sb2O3, wherein the mass ratio of ZrO2 / Al2O3 is 1.5-5.5 and the mass ratio of Al2O3 / Li2O is <0.

45.

2. The microcrystalline glass according to claim 1, characterized in that, Its average grain size is ≤50nm.

3. The microcrystalline glass according to claim 1 or 2, characterized in that, The microcrystalline glass has a Vickers hardness ≥750 kgf / mm², Young's modulus ≥90 GPa, ROR ≥1000 N, average drop height ≥0.4 m, average drop height ≥0.3 m with 80 grit sandpaper, and average drop height ≥0.6 m with 180 grit sandpaper.

4. The microcrystalline glass according to claim 1, characterized in that, The composition is as follows: SiO2 62-75 wt%, Al2O3 1-4 wt%, Na2O 0-3 wt%, K2O 0-1 wt%, Li2O 12-17 wt%, ZrO2 8-13 wt%, P2O5 2-5 wt%, CaO 0-3 wt%, SnO2 0-0.09 wt%, and Sb2O3 0-0.45 wt%.

5. The microcrystalline glass according to claim 1, characterized in that, The mass ratio of (CaO+Na2O+K2O) / Al2O3 in the raw materials is ≤0.

39.

6. A method for preparing microcrystalline glass as described in claim 1, characterized in that, Includes the following steps: Step 1: Prepare microcrystalline glass raw materials according to a certain mass ratio, mix them evenly, melt them into shape, and perform annealing treatment to obtain glass precursor; Step 2: The annealed glass precursor is subjected to crystallization heat treatment and then cooled and shaped.

7. The method for preparing microcrystalline glass according to claim 6, characterized in that, The microcrystalline glass raw materials in step 1 are SiO2 60-75wt%, Al2O3 1-6wt%, Na2O 0-4wt%, K2O 0-2wt%, Li2O 12-18wt%, ZrO2 6-15wt%, P2O5 2-6wt%, CaO 0-4wt%, SnO2 0-0.1wt%, and Sb2O3 0-0.5wt%; the melting process is as follows: melting temperature is 1400-1600℃, and melting time is 6-10h.

8. The method for preparing microcrystalline glass according to claim 6, characterized in that, The crystallization heat treatment in step 2 includes a nucleation stage and a crystallization stage. The temperature of the nucleation stage is 530-630℃, and the holding time is 1-10h. The temperature of the crystallization stage is 680-780℃, and the holding time is 1-10h.

9. An electronic device cover, made of the microcrystalline glass as described in claim 1 or 2.

10. An electronic device cover assembly made of the microcrystalline glass as described in claim 1 or 2.

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