阅读说明：本技术 微晶玻璃的化学强化方法、强化微晶玻璃及防护件 (Chemical strengthening method of microcrystalline glass, strengthened microcrystalline glass and protection piece ) 是由 覃文城 谈宝权 胡伟 吕路 袁小彬 王刚刚 于 2021-06-30 设计创作，主要内容包括：本申请公开了一种微晶玻璃的化学强化方法、强化微晶玻璃及防护件,该微晶玻璃的化学强化方法包括：提供一级强化微晶玻璃,一级强化微晶玻璃至少进行了一级离子交换,一级离子交换是利用钠离子交换微晶玻璃中的锂离子；将一级强化微晶玻璃置于二级强化盐浴中进行二级离子交换,得到强化微晶玻璃,二级强化盐浴包括锂盐。通过上述方式,本申请能够提高强化微晶玻璃的环境耐久性。(The application discloses a chemical strengthening method of microcrystalline glass, strengthened microcrystalline glass and a protection piece, wherein the chemical strengthening method of the microcrystalline glass comprises the following steps: providing first-stage reinforced glass ceramics, wherein the first-stage reinforced glass ceramics are subjected to at least first-stage ion exchange, and the first-stage ion exchange is to exchange lithium ions in the glass ceramics by using sodium ions; and (3) placing the first-stage strengthened microcrystalline glass in a second-stage strengthened salt bath for second-stage ion exchange to obtain the strengthened microcrystalline glass, wherein the second-stage strengthened salt bath comprises lithium salt. By the above mode, the environment durability of the reinforced glass ceramics can be improved.)

1. A chemical strengthening method of microcrystalline glass is characterized in that,

providing first-stage strengthened glass ceramics, wherein the first-stage strengthened glass ceramics are subjected to at least first-stage ion exchange, and the first-stage ion exchange is to exchange lithium ions in the glass ceramics by using sodium ions;

and placing the first-stage strengthened microcrystalline glass in a second-stage strengthened salt bath for second-stage ion exchange to obtain the strengthened microcrystalline glass, wherein the second-stage strengthened salt bath comprises lithium salt.

2. The chemical strengthening method of glass ceramics according to claim 1, wherein,

the content of lithium ions in the secondary strengthening salt bath is less than or equal to 200 ppm.

3. The chemical strengthening method of glass ceramics according to claim 2, characterized in that,

the content of lithium ions in the secondary strengthening salt bath is greater than or equal to 50ppm and less than or equal to 100 ppm.

4. The chemical strengthening method of glass-ceramics according to any one of claims 1 to 3, wherein the placing of the primary strengthened glass-ceramics in the secondary strengthening salt bath for secondary ion exchange comprises:

the temperature of the secondary ion exchange is 360-400 ℃, and the time is less than or equal to 30 min.

5. The chemical strengthening method of glass ceramics according to any one of claims 1 to 3, characterized in that,

the secondary strengthening salt bath comprises a mixture of potassium nitrate and lithium nitrate.

6. The chemical strengthening method of glass-ceramics according to any one of claims 1 to 3, characterized in that the step of placing the primary strengthened glass-ceramics in the secondary strengthening salt bath for secondary ion exchange comprises:

and pretreating the primary strengthened microcrystalline glass to ensure that the amount of lithium ions left on the surface of the treated primary strengthened microcrystalline glass cannot exceed a limited amount, wherein the limited amount is that when the primary strengthened microcrystalline glass is placed in a secondary strengthened salt bath, the amount of the lithium ions brought in by the primary strengthened microcrystalline glass cannot ensure that the content of the lithium ions in the secondary strengthened salt bath is more than 200 ppm.

7. The chemical strengthening method of glass ceramics according to claim 6, wherein the pretreatment of the primary strengthened glass ceramics comprises:

and (3) placing the first-stage strengthened glass ceramics in a transition salt bath to clean the first-stage strengthened glass ceramics, wherein the transition salt bath comprises sylvite.

8. The chemical strengthening method of glass ceramics according to claim 7, wherein the step of placing the first-stage strengthened glass ceramics in a transition salt bath to clean the first-stage strengthened glass ceramics comprises:

the cleaning temperature is less than or equal to 380 ℃, the cleaning time is less than or equal to 10min, and the content of lithium ions in the transition salt bath in the cleaning process is less than or equal to 150 ppm.

9. The chemical strengthening method of glass ceramics according to any one of claims 1 to 3, characterized in that the providing of the primary strengthened glass ceramics comprises:

placing the microcrystalline glass in a primary strengthening salt bath for primary ion exchange;

the temperature of the primary ion exchange is 420-460 ℃, and the time is 0.5-11 h.

10. The chemical strengthening method of glass ceramics according to claim 9, characterized in that,

the primary strengthening salt bath comprises pure sodium nitrate; or

The first-stage strengthened salt bath comprises a mixture of sodium nitrate and potassium nitrate, and the content of the sodium nitrate is greater than that of the potassium nitrate.

11. The chemical strengthening method of glass ceramics according to any one of claims 1 to 3, characterized in that the providing of the primary strengthened glass ceramics further comprises:

and placing the primary strengthened glass ceramics in a secondary salt bath for secondary ion exchange, wherein the secondary salt bath comprises potassium salt.

12. The chemical strengthening method of glass ceramics according to claim 11, wherein,

the secondary salt bath comprises pure potassium nitrate; or

The secondary salt bath comprises a mixture of sodium nitrate and potassium nitrate, and the content of the potassium nitrate is greater than that of the sodium nitrate.

13. A strengthened glass ceramics, characterized in that the content of sodium on the surface of the strengthened glass ceramics is less than or equal to 10 mol%.

14. The strengthened microcrystalline glass according to claim 13, wherein,

the main crystal phase of the strengthened microcrystalline glass is lithium disilicate.

15. The strengthened microcrystalline glass according to claim 13, wherein,

the secondary crystal phase of the strengthened glass ceramics comprises: one or more of lithium silicate, petalite, quartz and quartz solid solution.

16. The strengthened microcrystalline glass according to claim 13, wherein,

the crystallinity of the strengthened microcrystalline glass is greater than or equal to 70 percent.

17. The strengthened microcrystalline glass according to claim 13, wherein,

the content of lithium in the strengthened glass ceramics is more than or equal to 15mol percent.

18. The chemically strengthened glass-ceramic according to claim 13,

the strengthened glass ceramics has no erosion under the conditions that the temperature is 85 ℃ and the humidity is 85 percent, and the whitening degree is less than the second grade.

19. The strengthened microcrystalline glass according to claim 13, wherein,

the four-point bending strength B10 value of the strengthened microcrystalline glass is more than 650 MPa; the falling ball strength is more than 0.4 m.

20. An armor unit comprising the strengthened glass ceramic according to any one of claims 13 to 19.

Technical Field

The application relates to the field of dielectric materials, in particular to a chemical strengthening method of microcrystalline glass, strengthened microcrystalline glass and a protection piece.

Background

The microcrystalline glass is also called glass ceramic, is a composite material combining a crystal phase and glass, has the dual characteristics of glass and ceramic, has excellent optical properties and physicochemical properties of visible light transmission, high mechanical strength, excellent electrical insulation property, stable dielectric constant, wear resistance, corrosion resistance, adjustable thermal expansion coefficient and the like, and is widely applied to a plurality of fields, such as a protective cover plate material of portable electronic equipment, automobile protective glass and the like.

Chemically strengthened glass is a glass with high mechanical strength; the method utilizes a high-temperature ion exchange process to replace small alkali metal ions in glass by large alkali metal ions in high-temperature molten salt, thereby generating exchange plasma accumulation difference and generating high-to-low pressure stress on a certain surface layer of the glass, further hindering and delaying the expansion of glass microcracks and achieving the purpose of improving the mechanical strength of the glass. When the microcrystalline glass is chemically strengthened, the microcrystalline glass has a high content of sodium ions on the surface after ion exchange because of a high lithium content in the microcrystalline glass, which deteriorates the environmental durability of the microcrystalline glass.

Disclosure of Invention

The present application mainly solves the technical problem of providing a chemical strengthening method of a glass ceramic, a strengthened glass ceramic, and a protective element, which can improve the environmental durability of the strengthened glass ceramic.

In order to solve the technical problem, the application adopts a technical scheme that: provided is a method for chemically strengthening a glass ceramic, which comprises: providing first-stage reinforced glass ceramics, wherein the first-stage reinforced glass ceramics are subjected to at least first-stage ion exchange, and the first-stage ion exchange is to exchange lithium ions in the glass ceramics by using sodium ions; and (3) placing the first-stage strengthened microcrystalline glass in a second-stage strengthened salt bath for second-stage ion exchange to obtain the strengthened microcrystalline glass, wherein the second-stage strengthened salt bath comprises lithium salt.

Wherein the content of lithium ions in the secondary strengthening salt bath is less than or equal to 200 ppm.

Wherein the content of lithium ions in the secondary strengthening salt bath is not less than 50ppm and not more than 100 ppm.

Wherein the temperature of the secondary ion exchange is 360-400 ℃, and the time is less than or equal to 30 min.

Wherein the secondary strengthening salt bath comprises a mixture of potassium nitrate and lithium nitrate.

Wherein, before placing the first-stage strengthening microcrystalline glass in the second-stage strengthening salt bath for second-stage ion exchange, the method comprises the following steps: and (3) placing the first-stage strengthened microcrystalline glass in a transition salt bath to clean the first-stage strengthened microcrystalline glass, wherein the transition salt bath comprises sylvite.

Wherein the cleaning temperature is less than or equal to 380 ℃, the cleaning time is less than or equal to 10min, and the content of lithium ions in the transition salt bath in the cleaning process is less than or equal to 150 ppm.

Wherein, before placing the first-stage strengthening microcrystalline glass in a second-stage strengthening salt bath for second-stage ion exchange, the method comprises the following steps: and pretreating the primary strengthened microcrystalline glass to ensure that the amount of lithium ions left on the surface of the treated primary strengthened microcrystalline glass cannot exceed a limited amount, wherein the limited amount is that when the primary strengthened microcrystalline glass is placed in a secondary strengthened salt bath, the amount of the lithium ions brought in by the primary strengthened microcrystalline glass cannot ensure that the content of the lithium ions in the secondary strengthened salt bath is more than 200 ppm.

Wherein providing the first-order strengthened microcrystalline glass comprises: placing the microcrystalline glass in a primary strengthening salt bath for primary ion exchange; the temperature of the primary ion exchange is 420-460 ℃, and the time is 0.5-11 h.

Wherein the primary strengthening salt bath comprises pure sodium nitrate; or the first-stage strengthening salt bath comprises a mixture of sodium nitrate and potassium nitrate, and the content of the sodium nitrate is greater than that of the potassium nitrate.

Wherein, providing the first-order strengthened glass ceramics further comprises: and placing the primary strengthened microcrystalline glass in a secondary salt bath for secondary ion exchange, wherein the secondary salt bath comprises potassium salt.

Wherein the secondary salt bath comprises pure potassium nitrate; or the secondary salt bath comprises a mixture of sodium nitrate and potassium nitrate, and the content of potassium nitrate is greater than that of sodium nitrate.

In order to solve the above technical problem, another technical solution adopted by the present application is: provided is a strengthened glass ceramics, the surface of which has a sodium content of 10 mol% or less.

Wherein the main crystal phase of the strengthened microcrystalline glass is lithium disilicate.

Wherein the secondary crystal phase of the strengthened glass ceramics comprises: one or more of lithium silicate, petalite, quartz and quartz solid solution.

Wherein the crystallinity of the strengthened glass ceramics is more than or equal to 70 percent.

Wherein the lithium content in the strengthened glass ceramics is more than or equal to 15mol percent.

Wherein, the strengthened glass ceramics has no erosion and less blushing degree than the second grade under the conditions that the temperature is 85 ℃ and the humidity is 85 percent.

Wherein the four-point bending strength B10 value of the strengthened microcrystalline glass is more than 650 MPa; the falling ball strength is more than 0.4 m.

In order to solve the above technical problem, another technical solution adopted by the present application is: there is provided a protective shield comprising the strengthened glass ceramic of any one of the above.

The beneficial effect of this application is: the chemical strengthening process method of the microcrystalline glass is characterized in that a salt bath containing lithium is used for carrying out ion exchange on the microcrystalline glass, so that sodium ions in the sodium-lithium-exchanged strengthened microcrystalline glass are exchanged by lithium ions in the salt bath, and lithium-sodium reverse strengthening is actually carried out on the strengthened microcrystalline glass which is subjected to sodium-lithium exchange, so that sodium ion components on the surface of the strengthened microcrystalline glass are reduced, and the environmental durability of the strengthened microcrystalline glass is improved.

Drawings

FIG. 1 is a schematic representation of the four-point bending strength test of the present application;

FIG. 2 is a schematic illustration of the ball drop strength test of the present application;

FIG. 3 is a schematic diagram of a ball drop point in the ball drop strength test of the present application;

FIG. 4 is a schematic view of a strengthened glass-ceramic according to example 1 of the present application after a high-temperature and high-humidity treatment;

FIG. 5 is a schematic view of a strengthened glass-ceramic according to example 3 of the present application after a high-temperature and high-humidity treatment;

FIG. 6 is a schematic view showing glass cracking of a strengthened glass-ceramic according to comparative example 3 of the present application;

fig. 7 is a schematic view of the strengthened glass-ceramic of comparative example 7 of the present application after high-temperature and high-humidity treatment.

Detailed Description

In order to make the purpose, technical solution and effect of the present application clearer and clearer, the present application is further described in detail below with reference to the accompanying drawings and examples.

The microcrystalline glass material is formed by performing microcrystallization treatment on a glass substrate, so that small-sized crystals uniformly grow in the glass substrate, and the structural strength of the material can be greatly improved. The content of each alkali metal in the glass ceramics can influence the generation of a crystal structure and the ion exchange performance of the glass ceramics; the growth of a crystal structure is preferably considered in the design of the formula components of the microcrystalline glass, the ion exchange performance is considered subsequently, and the microcrystalline structure can block the ion exchange, so that the ion exchange performance of the microcrystalline glass is poor under the two factors. In order to balance crystallization performance and ion exchange performance, the lithium content in the finally designed microcrystalline glass formula is higher, and particularly compared with the conventional lithium aluminosilicate glass, the lithium content in the microcrystalline glass is far higher than that in the lithium aluminosilicate glass, so that after the microcrystalline glass is subjected to ion exchange, the surface sodium ion content of the microcrystalline glass is higher, and the environmental durability of the microcrystalline glass is further deteriorated.

Based on the above, the application provides a chemical strengthening process method for microcrystalline glass, which can adjust the alkali metal composition on the surface of the microcrystalline glass, improve the chemical stability of the microcrystalline glass and avoid the appearance defects by blending the salt bath ratio. The method can be applied to the strengthening of the microcrystalline glass containing the crystalline phase of lithium silicate or lithium disilicate, and can be used for the chemical strengthening of other microcrystalline glasses without being limited to the method.

The chemical strengthening process method of the microcrystalline glass is essentially to perform lithium-sodium reverse strengthening on the strengthened microcrystalline glass which has finished sodium-lithium exchange so as to reduce sodium ion components on the surface of the strengthened microcrystalline glass.

Specifically, the first-stage strengthened glass ceramics are placed in a second-stage strengthened salt bath for second-stage ion exchange, and the strengthened glass ceramics are obtained. The first-stage strengthening microcrystalline glass is strengthening microcrystalline glass which has completed sodium-lithium exchange, and the second-stage strengthening salt bath comprises lithium salt to realize lithium-sodium exchange.

In one embodiment, the content of lithium ions in the secondary strengthening salt bath is regulated to be less than or equal to 200ppm, so that the lithium-sodium reverse strengthening can be smoothly realized, and the monomer performance and the surface crack defect-free property of the strengthened glass can be ensured. This is because the salt bath containing lithium produces a certain corrosion effect on glass, and if the content of lithium ions in the salt bath is too high, the microcrystalline glass is corroded and damaged, and the surface of the microcrystalline glass generates a tensile stress phenomenon due to lithium-sodium exchange, and if the exchange amount is too large, the tensile stress causes surface microcracks. If the content of lithium ions is too low, lithium-sodium exchange is not complete; therefore, the lithium ion concentration in the salt bath needs to be strictly controlled.

Preferably, the content of lithium ions in the secondary strengthening salt bath is 50ppm or more and 100ppm or less, for example, 53ppm, 58ppm, 62ppm, 69ppm, 75ppm, 84ppm, 90ppm, and the like. In the ion exchange process, lithium is exchanged into the microcrystalline glass, and the concentration of lithium ions in the salt bath can be reduced, so that the concentration of the lithium ions can be controlled by regulating the initial concentration of the lithium ions in the salt bath without monitoring the concentration of the lithium ions in the ion exchange process.

In one embodiment, the secondary strengthening salt bath comprises a high-concentration potassium salt, and a small amount of lithium salt is added into the potassium salt to realize the control of the lithium ion content in the salt bath. Specifically, the secondary strengthening salt bath may be a mixture of potassium nitrate and lithium nitrate, and the secondary strengthening salt bath is prepared by adding lithium nitrate to molten high-concentration potassium nitrate.

In one embodiment, the temperature of the secondary ion exchange is 360-400 ℃, preferably 370-390 ℃, and the time is less than or equal to 30 min. Wherein, because the lithium-sodium exchange speed is higher, the ion exchange time of the reverse strengthening is not suitable to be too long, otherwise, the surface performance of the glass ceramics can be damaged. For example, the temperature can be 370 deg.C, 374 deg.C, 378 deg.C, 383 deg.C, 387 deg.C, 390 deg.C, etc., and the time can be 3min, 5min, 8min, 11min, 16min, 20min, 26min, 30min, etc.

In the above embodiment, by means of reverse strengthening ion exchange, sodium ion accumulation on the surface of the finally strengthened microcrystalline glass can be reduced, the appearance integrity of the strengthened glass is ensured, the durability and yield of the glass are improved, and the production, application and popularization of the microcrystalline glass are facilitated.

In one embodiment, the primary strengthened glass ceramics can be pretreated in advance, or directly purchased, or obtained by ion exchange of the glass ceramics on site, that is, the sodium-lithium exchange strengthening and the lithium-sodium exchange reverse strengthening of the glass ceramics can be continuously performed, and the primary ion exchange is performed for chemical strengthening first, and then the secondary ion exchange reverse strengthening is performed. The microcrystalline glass strengthening process method comprises the following steps:

s110: a glass ceramic is provided.

The microcrystalline glass may contain one or more of crystal phases such as lithium silicate, lithium disilicate, petalite, quartz, and β -quartz solid solution, and may specifically be a high-lithium-content microcrystalline of lithium disilicate or lithium silicate, that is, a microcrystalline glass whose main crystal phase is lithium silicate or lithium disilicate. The microcrystalline glass may have a crystallinity of 70% or more. The glass ceramics may also be glass ceramics having a lithium content of 15 mol% or more, and the specific crystal phase component is not limited.

S120: and (3) placing the microcrystalline glass in a primary strengthening salt bath for primary ion exchange.

The primary ion exchange is used for realizing the chemical strengthening of the microcrystalline glass, the alkali metal ions with large radius in the salt bath are used for exchanging the alkali metal lithium ions with small radius in the microcrystalline glass, and the pressure stress is formed on the surface of the microcrystalline glass by utilizing the difference of the exchanged plasma products, so that the effect of strengthening the microcrystalline glass is achieved.

The first-order ion exchange is mainly used for sodium-lithium exchange, and sodium ions in the salt bath are used for exchanging lithium ions in the glass ceramics. Wherein the primary strengthening salt bath comprises pure sodium salt or a mixture of sodium salt and potassium salt. In particular, it may be a pure sodium nitrate melt; a mixed solution of a sodium nitrate molten solution and a potassium nitrate molten solution may be used. When the salt bath is a mixed solution of sodium nitrate molten liquid and potassium nitrate molten liquid, the content of sodium nitrate in the salt bath should be greater than that of potassium nitrate, for example, the ratio of the two may be NaNO₃:KNO₃99:1, 98:2, 97:3, 95:5, etc. The temperature of the sodium-lithium exchange is 420-460 ℃, and the time is 0.5-11 h. E.g. at a temperature of 430 deg.C, 45 deg.C0 ℃, etc., for 1h, 3h, 5h, 8h, 10h, etc.

The first ion exchange may also include a potassium-sodium exchange, exchanging sodium ions in the glass-ceramic with potassium ions in the salt bath. Namely, the first-stage strengthened microcrystalline glass is placed in a secondary salt bath for secondary ion exchange. The secondary salt bath comprises a pure potassium salt or a mixture of sodium and potassium salts. Specifically, it may be a pure potassium nitrate melt; a mixed solution of a sodium nitrate molten solution and a potassium nitrate molten solution may be used. When the salt bath is a mixture of molten sodium nitrate and molten potassium nitrate, the content of potassium nitrate in the salt bath should be greater than that of sodium nitrate, for example, the ratio of potassium nitrate to sodium nitrate may be KNO₃:NaNO₃99:1, 98:2, 97:3, 95:5, etc. For example, when the glass ceramics contain a β -quartz solid solution crystal phase, a secondary ion exchange is required after the primary ion exchange. The temperature of the potassium-sodium exchange is 420-460 ℃, and the time is 0.5-11 h. For example, the temperature can be 430 ℃, 450 ℃ and the like, and the time can be 1h, 3h, 5h, 8h, 10h and the like.

S130: and (3) placing the first-stage strengthened microcrystalline glass in a transition salt bath for cleaning.

Wherein, because of the product that the one-level ion exchange was handled, takes out from the salt bath, more ion in the salt bath is adhered to on the glass surface, directly carry out next step's processing and be unfavorable for the control of ion content in the salt bath, especially be unfavorable for the control of lithium ion content, consequently, need wash before the second grade ion exchange. Namely, the primary strengthened glass ceramics needs to be pretreated, so that the amount of lithium ions left on the surface of the treated primary strengthened glass ceramics cannot exceed a limited amount, and the limited amount is that when the primary strengthened glass ceramics is placed in a secondary strengthened salt bath, the amount of the lithium ions brought in by the primary strengthened glass ceramics cannot enable the content of the lithium ions in the secondary strengthened salt bath to be more than 200 ppm.

On the one hand, the primary tempered glass can be cooled, then washed with water, ultrasonically cleaned, dried, preheated to the temperature of secondary tempering, and the like, and then placed in a secondary tempering salt bath. However, this method can prolong the process, and on the other hand, because the sodium ion content on the surface of the glass-ceramic is higher after the first-order ion exchange, the surface of the glass-ceramic can be corroded in the washing and drying processes.

In the process method provided by the application, the microcrystalline glass is cleaned by using the transition salt bath, the salt used by the transition salt bath can be selected according to the salt bath system used by the secondary ion exchange, and the salt bath with the same main component as the secondary strengthening salt bath can be selected; this can have less influence on the composition of the salt bath in the next step. In the application, the transition salt bath can be potassium salt, can be the same as the main component of the secondary strengthening salt bath, and can realize potassium-sodium exchange.

Alternatively, the transition salt bath may be selected from pure potassium salts, such as pure potassium nitrate melts. In another embodiment, waste potassium salt may be selected, for example, potassium salt used by potassium-sodium exchange, which can save cost and make full use of resources, but when waste potassium salt is selected, the content of components in the waste potassium salt should be considered, and if lithium ions are too much, the use is not recommended.

In one embodiment, the temperature of the cleaning is less than or equal to 380 ℃ and the time is less than or equal to 10 min. Specifically, the content of lithium ions in the transition salt bath during the cleaning process can be monitored, and the operation can be stopped when the content of lithium ions in the transition salt bath is less than or equal to 150 ppm. Alternatively, it may be stopped when the content of lithium ions in the transition salt bath does not affect the next ion exchange. The ions attached to the surface of the cleaned microcrystalline glass can not influence the salt bath ratio of the next ion exchange, and the cleaned microcrystalline glass can be directly put into the next salt bath for the next ion exchange reaction.

S140: and placing the cleaned first-stage strengthened microcrystalline glass in a second-stage strengthening salt bath for second-stage ion exchange.

The temperature of the secondary ion exchange is 360-400 ℃, the time is less than or equal to 10min, and the content of lithium ions in the secondary strengthening salt bath is controlled to be greater than or equal to 50ppm and less than or equal to 100 ppm.

Obtaining reinforced glass ceramics after secondary ion exchange; the sodium ion content of the surface of the obtained microcrystalline glass is low, and the environmental durability of the surface of the microcrystalline glass can be improved.

In one embodiment, the surface sodium ion content of the strengthened glass-ceramic may be less than or equal to 10 mol%, such as 3%, 5%, 8%, etc., as measured by XRF.

In one embodiment, the strengthened glass ceramics is subjected to a durability test in a high temperature and high humidity environment, for example, the strengthened glass ceramics is exposed to a high temperature of 85 ℃ and a humidity of 85%, no surface erosion phenomenon occurs within 10 days, and the glass whitening degree is 1-2 grade. Wherein, the degree of whitening is divided into 5 grades, which specifically comprises: no blushing, grade 1; slight whitish, wipeable, grade 2; moderate blushing, no swabability, grade 3; severe local blushing, grade 4; severe overall blushing, grade 5.

In one embodiment, the strengthened microcrystalline glass has better mechanical properties. The edge part of the surface of the steel plate is irradiated by a strong light lamp without small cracks (the cracks with the width of 1-5 microns are small cracks). Compared with the prior art, the sample prepared by the method has the advantages that the bending resistance and the impact resistance are improved by 20-30% under the condition of the same material.

Referring to FIG. 1, FIG. 1 is a schematic diagram of a four-point bending strength test according to the present application. The four-point bending strength test is carried out on the chemically strengthened glass, and the four-point bending strength B10 value of the strengthened glass ceramics is more than 650 MPa.

Referring to fig. 2 to 3, fig. 2 is a schematic diagram of a ball drop strength test of the present application, and fig. 3 is a schematic diagram of a ball drop point in the ball drop strength test of the present application. The chemical tempered glass is subjected to falling ball strength test, and the falling ball strength of the tempered glass ceramics is more than 0.4 m.

The reinforced glass ceramics can be suitable for electronic display equipment, is particularly suitable for the field of cover plate protection of electronic display equipment, and is also suitable for impact-resistant glass such as aircraft glass, automobile glass, high-speed rail glass and the like.

According to the embodiment, on the basis of considering ion exchange performance, the microcrystalline glass material, especially the microcrystalline of the lithium disilicate material and the lithium silicate material with high lithium content, is ensured to have sufficient ion exchange and obtain high-level stress, and sodium ion accumulation on the surface of a final reinforced sample is reduced through a reinforcing process design, and the reinforced appearance integrity is ensured. The strengthening mass production of the microcrystalline glass can be ensured, the durability and yield of the glass are improved, and the production, application and popularization of the microcrystalline glass are facilitated.

The present application will now be illustrated and explained by means of several groups of specific examples, which should not be taken to limit the scope of the present application.

The microcrystalline glass composition raw materials of the embodiments are respectively prepared, a microcrystalline glass substrate is prepared according to the formula of the microcrystalline glass composition in the embodiments, the microcrystalline glass substrate is subjected to heat treatment to obtain a microcrystalline glass preform, the components and the proportion of the microcrystalline glass preform are detailed in table 1, and the specific heat treatment process parameters are detailed in table 1. The obtained microcrystalline glass preform can be subjected to post-treatment, such as thinning by a chemical or physical thinning method, so as to adapt to different product requirements, and polishing treatment. Slicing, flat grinding and CNC processing the crystallized sample to prepare a sample with the specification of 150mm x 65mm x 0.7mm, and carrying out subsequent strengthening treatment; and (3) performing strengthening treatment on the treated microcrystalline glass preform to obtain the microcrystalline glass, wherein specific chemical strengthening treatment process parameters are detailed in tables 2 and 3 and figures 4-7. Various performance tests are carried out on the obtained microcrystalline glass, and the test results are detailed in tables 2 and 3 and figures 4-7.

TABLE 1 preparation of glass ceramics and Property parameters

		Glass 1	Glass 2	Glass 3	Glass 4
						Component 1	SiO2/mol％	70.0	68.5	71.0	66.5
Component 2	Al2O3/mol％	4.5	7.5	13.5	12
						Component 3	P2O5/mol％	0.5	1.0	0.5	0.5
Component 4	MgO/mol％	0.0	1.0	0.0	3.0
						Component 5	ZrO2/mol％	1.5	1.5	2.0	1.5
Component 6	Na2O/mol％	2.0	2.5	2.0	2.5
						Component 7	Li2O/mol％	21.0	17.0	9.5	13.0
Component 8	TiO2/mol％	0.5	1.0	1.5	1.0
							Main crystal phase	Lithium disilicate	Lithium disilicate	Solid solution of beta-quartz	Solid solution of beta-quartz
	Secondary crystal phase	Lithium silicate	Quartz	Spodumene, quartz	Spodumene
							Degree of crystallization/%)	90	85	70	60

TABLE 2 strengthening Process parameters and Performance parameters of microcrystalline glasses

TABLE 3 preparation of glass ceramics with Process parameters and Performance parameters

As can be seen from examples 1 to 4, after the primary strengthening process and the secondary strengthening process are adopted, the surface sodium of the glass ceramics is reduced to less than 10 mol%, which is good in the high temperature and high humidity performance test, and is only 2 grades at the highest, namely, the strengthened glass ceramics has no erosion under the conditions of 85 ℃ and 85% humidity, the whitening degree is less than two grades, and the surface is slightly whitened but can be erased, as shown in fig. 4 and 5, fig. 4 is a schematic diagram of the strengthened glass ceramics of example 1 after the high temperature and high humidity treatment, fig. 5 is a schematic diagram of the strengthened glass ceramics of example 3 after the high temperature and high humidity treatment, and the whitening degree is 1 grade, slightly whitened, and can be erased. And the surface has no micro cracks, the strong light flashlight observation glass is difficult to photograph and catch the cracks, the monomer performance is excellent, and the requirements are met.

As can be seen from comparative examples 1 to 4, if lithium ions in the secondary strengthening salt bath are not strictly controlled, surface microcracks occur after strengthening, as shown in fig. 6, fig. 6 is a schematic diagram of glass crack detection of the strengthened microcrystalline glass of comparative example 3, and the strengthened microcrystalline glass has obvious cracks and decreases the strength of the monomer.

As can be seen from the above comparative examples 5-8, if the secondary strengthening process is not performed, the surface of the glass has too many sodium ions, which results in severe erosion whitening phenomenon at high temperature and high humidity, as shown in FIG. 7, FIG. 7 is a schematic diagram of the test after the high temperature and high humidity treatment of the glass of comparative example 7 of the present application, the whitening degree is grade 3, and the glass is partially severely whitened and cannot be erased. This may result in failure of AF evaporation and reduced ink adhesion.

According to the scheme, on the basis of considering ion exchange performance, the microcrystalline glass material, especially the microcrystalline of the lithium disilicate and lithium silicate material with high lithium content, is ensured to have sufficient ion exchange and obtain high-level stress, and sodium ion accumulation on the surface of a final reinforced sample is reduced through the design of a reinforcing process, and the integrity of the reinforced appearance is ensured. The strengthening mass production of the microcrystalline glass can be ensured, the durability and yield of the glass are improved, and the production, application and popularization of the microcrystalline glass are facilitated.

The above description is only for the purpose of illustrating embodiments of the present application and is not intended to limit the scope of the present application, and all modifications of equivalent structures and equivalent processes, which are made by the contents of the specification and the drawings of the present application or are directly or indirectly applied to other related technical fields, are also included in the scope of the present application.