A transparent microcrystalline glass, its preparation method and uses

Abstract

This application provides a method for preparing transparent microcrystalline glass, comprising: (1) nucleating a glass substrate; (2) crystallizing the nucleated glass substrate; (3) heat-treating the crystallized glass substrate to obtain microcrystalline glass with an XRD diffraction peak height H≥870; wherein the heat treatment is divided into a heating section, a high-temperature section and a cooling section, wherein the heating section is divided into n heating sections, the high-temperature section is divided into k high-temperature sections, and the cooling section is divided into m cooling sections, wherein k is an integer obtained by rounding down (n+k+m) / 3, and 6≤n+k+m≤30; wherein the constant temperature T in the high-temperature section is... Ki The maximum value in is T Kmax And T Kmax =T g +△T2, where △T2 satisfies the following formula: H=(965.522±21.205)+(0.816±1.876)|(T g +△T2)-(715.212±5.120)|^(1.465±0.566); In the high-temperature section k, the temperature difference between any two adjacent heat treatment sections is within the range of 5~50℃. The microcrystalline glass produced by this process has excellent optical properties, improves the production yield of transparent microcrystalline glass covers, and has a short production time and high production efficiency.

Description

Technical Field

[0001] This application relates to the field of glass-ceramics, and more specifically, to transparent glass-ceramics, their preparation methods, and applications. Background Technology

[0002] With the advent of the smartphone era, mobile phones have become an indispensable communication tool in daily life. As the number of mobile phone users increases year by year, the pace of mobile phone upgrades and obsolescence is constantly accelerating to meet user demands and enhance the user experience. From the initial 2D glass to 2.5D glass and now to 3D glass, mobile phone cover glass has not only increased the novelty of mobile phone products in terms of appearance but also improved the user's tactile experience.

[0003] Glass is used as a cover glass for mobile phones not only because of its excellent mechanical properties but also because of its high transparency. Ordinary glass does not undergo changes in optical properties during heat treatment. However, glass-ceramics are composed of a glass phase and a crystalline phase, and during heat treatment, crystals of varying sizes are formed within them. The crystalline phases contained in glass-ceramics at different crystallization states exhibit certain differences. Studies have shown that the refractive index difference between the crystalline phase and the glass phase is the main reason for the deterioration of the optical properties of glass-ceramics. For lithium aluminum silicon system (LAS) glass-ceramics, lithium silicate (Li₂SiO₃) and β-quartz (β-SiO₂) can degrade the optical properties of glass-ceramics. Lithium silicate (Li₂SiO₃) mainly occurs during periods of low crystallinity and over-crystallization, while β-quartz (β-SiO₂) mainly occurs during over-crystallization.

[0004] Different heat treatment processes can yield glass-ceramics with different crystal states, and these glass-ceramics with different crystal states have certain differences in optical properties. During the heat treatment process, abnormal crystallization of the glass-ceramics is unavoidable, resulting in the glass sheet turning white.

[0005] Therefore, it is of great significance to obtain transparent glass-ceramics with excellent optical properties during the heat treatment process. This can not only improve the quality of glass-ceramics, but also increase the production yield of glass-ceramics, thereby reducing production costs. Summary of the Invention

[0006] Therefore, the purpose of this application is to provide a transparent glass-ceramic, its preparation method, and its uses. For the crystallized glass substrate, this application starts with a heat treatment process and controls relevant process parameters to obtain a glass-ceramic with an XRD diffraction peak height H ≥ 870. The prepared glass-ceramic has excellent optical properties, and the process is time-efficient, with high production yield and efficiency.

[0007] In a first aspect, this application provides a method for preparing transparent microcrystalline glass, characterized in that the method includes the following steps:

[0008] (1) Nucleation of the original glass slide;

[0009] (2) Crystallize the nucleated glass substrate;

[0010] (3) Heat-treat the crystallized glass sheet to obtain a microcrystalline glass with an XRD diffraction peak height H≥870;

[0011] The heat treatment is divided into a heating section, a high-temperature section, and a cooling section. The heating section is divided into n heating sections, the high-temperature section is divided into k high-temperature sections, and the cooling section is divided into m cooling sections. k is an integer rounded down to (n+k+m) / 3, and 6≤n+k+m≤30.

[0012] Each high-temperature section has a constant temperature T. Ki i = 1, 2, 3...;

[0013] The constant temperature T in the k-segment high-temperature section Ki The maximum value in is T Kmax And T Kmax =T g +△T2, the T g This refers to the glass transition point temperature of the original glass sheet.

[0014] Wherein, △T2 satisfies the following formula:

[0015] H=(965.522±21.205)+(0.816±1.876)|(T g +△T2)-(715.212±

[0016] 5.120)|^(1.465±0.566);

[0017] Furthermore, in the k-segment high-temperature section, the temperature difference between any two adjacent heat treatment sections is within the range of 5 to 50°C.

[0018] In some embodiments, the nucleation temperature is T. g +10℃~T g +80℃, nucleation time is 120~360min.

[0019] In some embodiments, the crystallization temperature is T. g +△T1, the crystallization time is 30 to 150 min; wherein 100℃≤△T1≤150℃.

[0020] In some embodiments, the XRD diffraction peak height H of the microcrystalline glass is 960–1150.

[0021] In some implementations, the processing times of the k-segment high-temperature segment, the n-segment heating segment, and the m-segment cooling segment are each independently selected from 10 to 90 seconds.

[0022] In some embodiments, the temperature difference between any two adjacent heat treatment sections in the n heating sections is in the range of 10 to 150°C; optionally, the temperature difference between any two adjacent heat treatment sections in the m cooling sections is in the range of 10 to 150°C.

[0023] In some embodiments, the temperature difference between any two adjacent heat treatment sections in the k-segment high-temperature section is in the range of 5 to 30°C, preferably in the range of 10 to 20°C.

[0024] In some embodiments, the glass substrate is lithium aluminum silicon glass.

[0025] In some embodiments, the glass substrate contains the following components, expressed in mol%:

[0026]

[0027] Secondly, this application provides a microcrystalline glass prepared by the above method, characterized in that the XRD diffraction peak height H of the microcrystalline glass is ≥870, preferably 960~1150;

[0028] Preferably, the b-value of the microcrystalline glass is ≤0.4;

[0029] Preferably, the content of lithium disilicate and petalite in the microcrystalline glass is 90-100%;

[0030] Preferably, the content of lithium silicate and β-quartz crystal phase in the microcrystalline glass is 0-10%.

[0031] Thirdly, this application provides an application for the microcrystalline glass prepared by the above method, characterized in that the microcrystalline glass is used as a cover for a mobile phone, a cover for a tablet computer, a cover for a watch, or a cover for an automotive display.

[0032] This application has the following beneficial technical effects:

[0033] This application, starting from the heat treatment process, divides the heat treatment into three stages: a heating stage, a high-temperature stage, and a cooling stage. It controls the maximum temperature T in the high-temperature stage. Kmax =T g +△T2, where △T2 satisfies: H=(965.522±21.205)+(0.816±1.876)|(T gThe method of +△T2)-(715.212±5.120)|^(1.465±0.566) is used to obtain microcrystalline glass with XRD diffraction peak height H≥870. The microcrystalline glass produced by this process has excellent optical properties; especially when the diffraction peak height H of the obtained microcrystalline glass is controlled to be 960-1150, microcrystalline glass with b value ≤0.4 can be obtained; moreover, this process improves the production yield of transparent microcrystalline glass covers, has a short production time, and high production efficiency. Attached Figure Description

[0034] To more clearly illustrate the technical solutions of the embodiments of this application, the prior art and the accompanying drawings used in the embodiments of this application 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.

[0035] Figure 1 - Relationship between the highest XRD peak height (H) and b value after heat treatment of lithium aluminum silicon microcrystalline glass. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0037] The following describes in detail the transparent microcrystalline glass, its preparation method, and its uses according to embodiments of this application.

[0038] This application provides a method for preparing transparent microcrystalline glass, the method comprising the following steps:

[0039] (1) Nucleation of the original glass slide;

[0040] (2) Crystallize the nucleated glass substrate;

[0041] (3) The crystallized glass sheet is heat-treated to obtain a microcrystalline glass with an XRD diffraction peak height H ≥ 870. Specifically, the diffraction peak height H can be 900, 820, 940, 960, 980, 1000, 1020, 1040, 1060, 1080, 1100, 1120, 1140, 1160, 1170, etc. Preferably, the diffraction peak height H is 960 to 1150. More preferably, the diffraction peak height H is 980 to 1132.

[0042] The heat treatment is divided into a heating section, a high-temperature section, and a cooling section. The heating section is further divided into n heating sections, namely N1, N2, N3...N n The high-temperature section is divided into k high-temperature sections, namely K1, K2, K3...K k The cooling section is divided into m cooling sections, namely M1, M2, M3...M m The k is an integer obtained by rounding down (n+k+m) / 3, where 6≤n+k+m≤30.

[0043] In the heat treatment process, the heating and cooling sections play the role of preheating and cooling the glass-ceramic. If the glass is placed directly from a low temperature environment to a high temperature environment or from a high temperature environment to a low temperature environment, it is easy to cause uneven heating and cooling of the glass, which can lead to breakage. The high temperature section is the secondary crystallization section of the glass-ceramic. After the high temperature heat treatment of section k, the crystal growth in the glass-ceramic is more mature, which is reflected in the increased crystallinity of the glass-ceramic. Through experiments, the inventors discovered that for glass-ceramics that are relatively easy to crystallize, such as lithium aluminum silicon system glass-ceramics, the total number of heat treatment stages can be relatively small. When 6 ≤ n + k + m ≤ 15, glass-ceramics with a crystallinity greater than 90% can be obtained. For glass-ceramics that are more difficult to crystallize, such as spinel system glass-ceramics, the number of heat treatment stages can be appropriately increased. That is, when 15 ≤ n + k + m ≤ 30, glass-ceramics with a crystallinity greater than 90% can be obtained. However, when the number of heat treatment stages is greater than 30, since the state of the obtained glass-ceramics is almost the same as that obtained when the number of heat treatment stages is 30, it can be considered that the crystallization of the glass-ceramics is saturated when the number of heat treatment stages increases to 30. Therefore, considering efficiency and cost, the total number of heat treatment stages should be controlled within the range of 6 ≤ n + k + m ≤ 30.

[0044] Specifically, n+k+m can be 7, 8, 9, 10, 12, 14, 16, 18, 20, 21, 22, 25, 27, 28, etc.; preferably, the number of heating segments and cooling segments are equal or similar. For example, when n+k+m = 9 segments, the high-temperature segment is 9 / 3 = 3 segments, and the heating segment and cooling segment are each 3 segments; when n+k+m = 10 segments, the high-temperature segment is the integer part of 10 / 3, which is 3 segments, and the heating segment and cooling segment can be 3 segments and 4 segments respectively; when n+k+m = 11 segments, the high-temperature segment is the integer part of 11 / 3, which is 3 segments, and the heating segment and cooling segment can each be 4 segments.

[0045] Each high-temperature section has a constant temperature T. Ki i = 1, 2, 3...;

[0046] The constant temperature T in the k-segment high-temperature section Ki The maximum value in is T Kmax And T Kmax=Tg + △T2, where T g This refers to the glass transition point temperature of the original glass sheet.

[0047] Wherein, △T2 satisfies the following formula:

[0048] H=(965.522±21.205)+(0.816±1.876)|(T g +△T2)-(715.212±

[0049] 5.120)|^(1.465±0.566);

[0050] Furthermore, in the k-segment high-temperature section, the temperature difference between any two adjacent heat treatment sections is within the range of 5 to 50°C. Specifically, the temperature difference can be 8°C, 10°C, 15°C, 18°C, 20°C, 25°C, 30°C, 35°C, 40°C, or 45°C, etc. Preferably, the temperature difference is within the range of 5 to 30°C, and more preferably, the temperature difference is within the range of 10 to 20°C.

[0051] In some embodiments, the nucleation temperature is T. g +10℃~T g The nucleation temperature is +80℃, and the nucleation time is 120–360 min. Specifically, the nucleation temperature can be T. g +20℃, T g +30℃, T g +40℃, T g +50℃, T g +60℃, or T g +70℃, etc.; nucleation time is 130min, 150min, 180min, 200min, 240min, 260min, 300min, 320min or 340min, etc.

[0052] In some embodiments, the crystallization temperature is T. g +△T1, wherein the crystallization time is 30–150 min; wherein 100℃≤△T1≤150℃. Specifically, △T1 can be 110℃, 115℃, 120℃, 125℃, 130℃, 135℃, 140℃, or 145℃, etc.; the crystallization time can be 35 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, 120 min, 130 min, or 140 min, etc.

[0053] The inventors discovered that by setting different crystallization and heat treatment processes during the nucleation, crystallization and heat treatment of glass, microcrystalline glass with different crystal states can be obtained. Correspondingly, the maximum XRD diffraction peak height of the microcrystalline glass also has a certain variation law.

[0054] During crystallization and heat treatment, by adjusting the temperatures ΔT1 during crystallization and ΔT2 during the high-temperature section of heat treatment, microcrystalline glass with different XRD maximum diffraction peak heights H can be obtained. The relationship between the two is as follows:

[0055] When the highest XRD diffraction peak height is less than 870:

[0056] H = -(0.23197 ± 0.02596)△T1^ 3 +(86.57095±9.6945)△T1^ 2 -

[0057] (10724.28028±1205.81659)△T1+(441572.3243±49947.99012)····Formula 1;

[0058] When the highest XRD diffraction peak height is greater than 870:

[0059] H=(965.522±21.205)+(0.816±1.876)|(T g +△T2)-(715.212±

[0060] 5.120)|^(1.465±0.566)····Equation 2.

[0061] Among them, the highest diffraction peak height H of the glass obtained during crystallization is less than 870. According to Formula 1, the specific range of diffraction peak height H can be determined by adjusting the value of the relevant parameter ΔT1 in the crystallization process. At this time, the crystal growth of the microcrystalline glass is not yet mature, and the crystallinity of the microcrystalline glass is low, with crystallinity y≤70%, that is, the transparency of the glass in this state is poor.

[0062] To further improve the transparency of glass, the crystallized glass needs to be heat-treated to increase the crystallinity of the glass-ceramic. As the crystallinity y ≥ 70%, the crystal growth of the glass-ceramic gradually matures, and the corresponding maximum XRD diffraction peak height begins to increase, reaching H ≥ 870. Glass in this state requires increasing the heat treatment temperature. Referring to Equation 2, the specific range of the diffraction peak height H can be determined by adjusting the relevant temperature parameter ΔT2 in the high-temperature section of the heat treatment process.

[0063] The inventors further discovered that the height of the highest XRD diffraction peak and the b-value of the microcrystalline glass exhibit certain variation patterns. Figure 1The graph shows the relationship between the highest XRD diffraction peak height (H) and b-value of lithium aluminum silicon-based glass-ceramics after heat treatment. The graph uses the highest XRD diffraction peak height of the glass-ceramic sheet as the x-axis and the b-value as the y-axis. When the highest XRD diffraction peak height is less than 870°, the b-value of the glass-ceramic is greater than 0.4. At this point, the main crystalline phases contained in the glass include lithium silicate (Li₂SiO₃) and petalite (LiAlSi₄O₃). 10 When the highest XRD diffraction peak height is greater than 870, especially when the peak height is between 960 and 1150, the b-value of the glass-ceramic is ≤0.40. At this time, the main crystalline phases contained in the glass are lithium disilicate (Li2Si2O5) and petalite (LiAlSi4O3). 10 It contains a small amount of lithium silicate (Li2SiO3) and a small amount of β-quartz (β-SiO2) crystal phase (or no β-quartz (β-SiO2) crystal phase); when the peak height H is 960, as shown by point A in the figure, the glass has just reached the state of complete crystallization. At this time, the lithium silicate (Li2SiO3) crystal phase is basically completely transformed into the lithium disilicate (Li2Si2O5) crystal phase (even if there is residual incompletely crystallized lithium silicate, its content is small). This point is the starting point of complete crystallization. When the peak height H reaches 1150, as shown by point B in the figure, the glass is still in the state of complete crystallization. This point is the end point of complete crystallization. When the highest XRD diffraction peak height exceeds 1150, i.e., past point B, the b-value will be greater than 0.40. As the peak height increases, the b-value continues to rise. At this point, overcrystallization has occurred in the glass-ceramic, resulting in the re-formation of impurity phases such as lithium silicate (Li₂SiO₃) and β-quartz (β-SiO₂). In other words, the main crystalline phases in the glass are lithium disilicate (Li₂Si₂O₅) and petalite (LiAlSi₄O₂). 10 It contains a small amount of lithium silicate (Li2SiO3) and a small amount of β-quartz (β-SiO2) crystal phase (or no β-quartz (β-SiO2) crystal phase).

[0064] Complete crystallization: In the glass-ceramic, the lithium silicate (Li2SiO3) crystal phase is completely transformed into the lithium disilicate (Li2Si2O5) crystal phase, and there are no (or few) lithium silicate (Li2SiO3), β-quartz (β-SiO2) and other crystal phases.

[0065] Overcrystallization: The glass-ceramic reaches complete crystallization, and crystalline phases such as lithium silicate (Li2SiO3) and β-quartz (β-SiO2) are generated simultaneously.

[0066] b-value: This is the yellow-blue value. The b-value test is based on transmitted light. A positive b-value indicates that less blue light is transmitted, meaning more blue light is reflected. The larger the b-value, the bluer the glass.

[0067] This application incorporates Formula 2: H=(965.522±21.205)+(0.816±1.876)|(Tg +△T2)-(715.212±5.120)|^(1.465±0.566), by adjusting the value of the relevant process parameter △T2 in the high-temperature section of the heat treatment process, the range of the highest XRD diffraction peak height of the heat-treated microcrystalline glass cover can be determined, so that the peak height H is greater than 870, preferably in the range of 960 to 1150. This can minimize the formation of lithium silicate and β-quartz crystal phases, thereby obtaining a transparent microcrystalline glass cover with excellent optical performance.

[0068] In some implementations, the processing times for the k-segment high-temperature segment, the n-segment heating segment, and the m-segment cooling segment are each independently selected from 10 to 90 seconds; specifically, the processing times can be 15 seconds, 20 seconds, 25 seconds, 30 seconds, 35 seconds, 40 seconds, 45 seconds, 50 seconds, 55 seconds, 60 seconds, 65 seconds, 70 seconds, 75 seconds, 80 seconds, or 85 seconds, etc. By controlling the time of each segment, the diffraction peak height can be controlled, and microcrystalline glass with excellent optical properties can be obtained, while reducing production time and improving production efficiency.

[0069] In some embodiments, the temperature difference between any two adjacent heat treatment sections in the n heating sections is within the range of 10 to 150°C; specifically, the temperature difference can be 15°C, 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, or 140°C, etc. Optionally, the temperature difference between any two adjacent heat treatment sections in the m cooling sections is within the range of 10 to 150°C; specifically, the temperature difference can be 15°C, 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, or 140°C, etc.

[0070] In some embodiments, the glass substrate is lithium aluminum silicon glass. Preferably, the glass contains the following components (mol%): SiO2 65-72% (e.g., 66%, 67%, 68%, 69%, 70%, or 71%), Al2O3 3-7% (e.g., 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, or 6.5%), ZrO2 0.5-5% (e.g., 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, or 4.5%), Li2O 15-25% (e.g., 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, or 24%), Na2O 0-2% (e.g., 0.1%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, or 1.9%), P2O5 0.5%–2% (e.g., 0.7%, 0.9%, 1%, 1.2%, 1.5%, 1.8%, or 1.9%), B₂O₃ 0–2% (e.g., 0.1%, 0.5%, 1%, 1.2%, 1.5%, 1.8%, or 1.9%), MgO 0–3% (e.g., 0.1%, 0.5%, 0.7%, 0.9%, 1%, 1.2%, 1.5%, 1.8%, 2.4%, 2.7%, or 2.9%), ZnO 0–3% (e.g., 0.1%, 0.3%, 0.6%, 0.9%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.5%, or 2.7%).

[0071] This application further provides a microcrystalline glass prepared by the above method, wherein the XRD diffraction peak height H of the microcrystalline glass is ≥870, preferably 960-1150; more preferably 980-1132;

[0072] Preferably, the b-value of the microcrystalline glass is ≤0.4; specifically, the b-value can be 0.39, 0.38, 0.37, 0.36, 0.35, 0.34, 0.33, 0.32, 0.31 or 0.3, etc.

[0073] Preferably, the content of lithium disilicate and petalite in the microcrystalline glass is 90-100%; specifically, the content can be 91%, 93%, 94%, 95%, 97% or 99%, etc.

[0074] Preferably, the content of lithium silicate and β-quartz crystal phase in the microcrystalline glass is 0-10%, more preferably, the content is ≤5%; more preferably, the content is 0%.

[0075] This application further provides an application of the microcrystalline glass prepared by the above method, wherein the microcrystalline glass is used as a cover for a mobile phone, a cover for a tablet computer, a cover for a watch, or a cover for an automotive display.

[0076] Example

[0077] To further illustrate and explain the technical solution of this application, the following non-limiting embodiments are provided.

[0078] Glass raw materials are prepared to obtain the glass in Table 1, expressed in mol% based on oxides. After mixing, the materials are melted and formed by methods including float glass, overflow glass, rolling glass, and casting glass. After forming, the glass sheets are annealed, cut and polished to obtain glass sheets of the same size with a thickness of 0.58 mm ± 0.02 mm.

[0079] For the glass transition temperature T in Table 1 g The following methods will be used for evaluation:

[0080] Differential thermal analysis (DSC) was used to obtain the glass's DSC curve. The temperature corresponding to the onset of the first exothermic peak on this curve is the glass transition temperature T. g .

[0081] Table 1

[0082]

[0083]

[0084] The obtained glass substrate was prepared under the conditions recorded in Table 2-5; the crystallization process column of the table records the value of ΔT1, where the specific crystallization temperature is T. g +△T1. The heat treatment process column in the table records the heat treatment regimes for glasses 1 to 5. △T2 is equal to the highest heat treatment temperature in the high-temperature range minus the glass transition temperature T. g In the "Crystal Content" column of Table 2-5, letters A, B, C, and D represent lithium feldspar, lithium disilicate, lithium silicate, and quartz crystal phases, respectively. The crystal content in Table 2-5 indicates the proportion of the referred crystal's mass to the total mass of crystals in the glass.

[0085] The diffraction peak height, precipitated crystals, and glass b-value in Table 2-5 are evaluated using the following methods:

[0086] 1. Glass b-value: The crystallized glass slide was cleaned in an ultrasonic cleaner under the following conditions: cleaning time: 5-10 min; cleaning agent: commonly used detergent diluted 10 times; cleaning temperature: 45℃-65℃; cleaning frequency: 20kHz-40kHz. The transmittance and b-value of the glass at different wavelengths were then measured using a haze meter according to the standard GB / T7962.12-2010 "Test Methods for Colorless Optical Glass Part 12: Spectral Transmittance". The haze meter used in this application was a Konica Minolta CM-3600A spectrophotometer.

[0087] 2. Diffraction Peak Height: The crystallized microcrystalline glass slides were ground into fine glass powder with a particle size of less than 75 μm using a pulverizer. X-ray diffraction (XRD) was then used to measure the powder, obtaining the XRD diffraction peak curve. Finally, the XRD glass diffraction peak height was obtained using JADE software.

[0088] The X-ray diffractometer used in this application is a Shimadzu XRD-6100. The incident angle range used in the test is 2Theta=10-80°, the scanning speed is 6° / min, the operating voltage is 40KV, and the operating current is 30KA.

[0089] 3. Precipitation of crystals:

[0090] The crystalline phases contained in glass-ceramics were analyzed using the JCPDS card library in JADE software.

[0091] Table 2 Examples 1-10

[0092]

[0093]

[0094] Table 3 Examples 11-20

[0095]

[0096]

[0097] Table 4 Examples 21-30

[0098]

[0099]

[0100] Table 5 Examples 31-40

[0101]

[0102]

[0103] Performance test results explanation:

[0104] Examples 1-8 involved treating the original glass sheet of Glass 1 under different crystallization and heat treatment processes. Examples 1-6 used the same nucleation and crystallization processes, but different heat treatment processes. The main difference in the heat treatment process was the varying heat treatment temperature in the high-temperature range, i.e., different ΔT2. Example 1 had the highest ΔT2, resulting in the highest XRD peak height H after heat treatment, reaching 1155. The resulting glass phase contained lithium silicate due to over-crystallization, with a glass b-value of 0.43, exhibiting poorer optical performance compared to the other examples. In contrast, Example 6 had the lowest diffraction peak height H. Although the crystalline phase contained incompletely crystallized lithium silicate (2%), the glass b-value was 0.38. Comparing Examples 1, 7, and 8 shows that under the same nucleation process, the highest XRD peak height H after crystallization increases with increasing crystallization temperature.

[0105] Examples 9-16 involve treating the original glass sheets of glass 2 under different heat treatment processes. The main difference in heat treatment processes is reflected in the different ΔT2 values. In Example 9, the ΔT2 and diffraction peak height H are the highest, lithium silicate is also present in the crystal phase, and the glass b value exceeds 0.4. Compared with the other examples, the optical performance is poor.

[0106] Examples 17-22 involve treating the original glass sheets of glass 3 under different heat treatment processes. The main difference in heat treatment processes is reflected in the different ΔT2 values. In Example 17, the ΔT2 and diffraction peak height H are the highest, and lithium silicate is also present in the crystal phase. Compared with the other examples, the optical performance is poor.

[0107] Examples 25-30 involved treating the original glass sheets of Glass 4 under different heat treatment processes. The main difference in the heat treatment processes was the difference in ΔT2. In Example 25, ΔT2 and diffraction peak height H were the highest, and lithium silicate was also present in the crystalline phase. Compared with the other examples, the optical performance was poor. In contrast, in Example 30, ΔT2 and diffraction peak height H were the lowest compared with the other examples, and the content of incompletely crystallized lithium silicate in the crystalline phase was relatively high, reaching 1%, resulting in a b-value of 0.38 for the obtained glass.

[0108] Examples 33-38 involve treating the original glass sheet of glass 5 under different heat treatment processes. The main difference in heat treatment processes is reflected in the different ΔT2. Among them, Example 33 has the highest ΔT2 and diffraction peak height H, and lithium silicate also appears in the crystal phase. Compared with the other examples, the optical performance is poor.

[0109] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for preparing a microcrystalline glass, wherein the microcrystalline glass is a lithium aluminum silicon-based microcrystalline glass; characterized in that, The desired b-value for the glass-ceramic is obtained by adjusting the height H of the highest XRD diffraction peak. in: When the b-value of the required glass crystal is >0.4, the maximum XRD diffraction peak height H is adjusted to be <870 or >1150. When the b-value of the required glass crystal is ≤0.40, the height H of the highest XRD diffraction peak is adjusted to 870~1150. The height H of the highest XRD diffraction peak can be controlled by setting different crystallization and heat treatment processes. When the b-value of the desired glass crystal is greater than 0.4, the glass substrate is crystallized by adjusting the temperature ΔT1 during the crystallization process to obtain a glass crystal with the highest XRD diffraction peak height H < 870. The temperature of the crystallization treatment is T. g +△T1, the crystallization treatment time is 30~150 min, where 100℃≤△T1≤150℃; Wherein, △T1 satisfies the following formula: H=-(0.23197±0.02596)△T1^ 3 +(86.57095±9.6945)△T1^ 2 -(10724.28028±1205.81659)△T1+(441572.3243±49947.99012); When the b-value of the required glass crystal is greater than 0.4, the glass substrate is heat-treated after crystallization. By adjusting the temperature ΔT2 during heat treatment, glass crystal with the highest XRD diffraction peak height H > 1150 can be obtained. The heat treatment is divided into a heating section, a high-temperature section, and a cooling section. The heating section is divided into n heating sections, the high-temperature section is divided into k high-temperature sections, and the cooling section is divided into m cooling sections. k is an integer rounded down to (n+k+m) / 3, and 6≤n+k+m≤30. Each high-temperature section has a constant temperature T. Ki i = 1, 2, 3...; The constant temperature T in the k-segment high-temperature section Ki The maximum value in is T Kmax And T Kmax =T g +△T2, the T g This refers to the glass transition point temperature of the original glass sheet. Wherein, △T2 satisfies the following formula: H=(965.522±21.205)+(0.816±1.876)|(T g +△T2)-(715.212±5.120)|^(1.465±0.566); Furthermore, in the k-segment high-temperature section, the temperature difference between any two adjacent heat treatment sections is within the range of 5 to 50°C. When the b-value of the required microcrystalline glass is ≤0.4, the glass substrate is heat-treated after crystallization. The highest XRD diffraction peak height H is obtained by adjusting the temperature ΔT2 during heat treatment to 870~1150. The heat treatment is divided into a heating section, a high-temperature section, and a cooling section. The heating section is divided into n heating sections, the high-temperature section is divided into k high-temperature sections, and the cooling section is divided into m cooling sections. k is an integer rounded down to (n+k+m) / 3, and 6≤n+k+m≤30. Each high-temperature section has a constant temperature T. Ki i = 1, 2, 3...; The constant temperature T in the k-segment high-temperature section Ki The maximum value in is T Kmax And T Kmax =T g +△T2, the T g This refers to the glass transition point temperature of the original glass sheet. Wherein, △T2 satisfies the following formula: H=(965.522±21.205)+(0.816±1.876)|(T g +△T2)-(715.212±5.120)|^(1.465±0.566); Furthermore, in the k-segment high-temperature section, the temperature difference between any two adjacent heat treatment sections is within the range of 5 to 50°C.

2. The method for preparing microcrystalline glass as described in claim 1, characterized in that, The glass substrate used to prepare the microcrystalline glass contains the following components, expressed in mol%:

3. A microcrystalline glass prepared by the method according to any one of claims 1 to 2, characterized in that, The highest XRD diffraction peak height H of the glass-ceramic is 870~1150, and the b value is ≤0.

40. The main crystalline phases of the glass-ceramic are lithium disilicate and petalite.

4. The microcrystalline glass as described in claim 3, characterized in that, The microcrystalline glass is in a fully crystalline state, and the highest XRD diffraction peak height H is 960-1150.

5. The microcrystalline glass as described in claim 4, characterized in that, The highest XRD diffraction peak height H of the microcrystalline glass is 980-1132.

6. The microcrystalline glass according to any one of claims 3 to 5, characterized in that, In the microcrystalline glass, the mass content of lithium disilicate and petalite is 90-100%.

7. The microcrystalline glass according to any one of claims 3 to 5, characterized in that, In the microcrystalline glass, the mass content of lithium silicate and β-quartz crystal phase is 0-10%.

8. The microcrystalline glass as described in claim 7, characterized in that, In the microcrystalline glass, the mass content of lithium silicate and β-quartz crystal phase is ≤5%.

9. The microcrystalline glass as described in claim 8, characterized in that, The mass content of lithium silicate and β-quartz crystal phase in the microcrystalline glass is 0%.

10. The microcrystalline glass according to claim 3, characterized in that, The b-value of the microcrystalline glass is 0.3 to 0.

39.

11. A microcrystalline glass prepared by the method according to any one of claims 1 to 2, characterized in that, The highest XRD diffraction peak height of the glass-ceramic is H < 870, and the b value is > 0.

4. The main crystalline phases of the glass-ceramic include lithium silicate and petalite.

12. A microcrystalline glass prepared by the method according to any one of claims 1 to 2, characterized in that, The highest XRD diffraction peak height of the glass-ceramic is H > 1150, and the b value is > 0.

4. The main crystalline phases of the glass-ceramic are lithium disilicate and petalite, and it also contains a small amount of lithium silicate; or it contains a small amount of lithium silicate and a small amount of β-quartz.

13. The use of a microcrystalline glass prepared by the method according to any one of claims 1 to 2, characterized in that, The microcrystalline glass is used as a cover for mobile phones, tablets, watches, or automotive displays.

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