Low surface pressure stress strengthened glass ceramic and original glass
阅读说明：本技术 一种低表面压应力的强化玻璃陶瓷及原片玻璃 (Low surface pressure stress strengthened glass ceramic and original glass ) 是由 胡伟 谈宝权 张延起 覃文城 于 2019-08-28 设计创作，主要内容包括：一种低表面压应力的强化玻璃陶瓷,该强化玻璃陶瓷的表面压应力在100-450Mpa之间,压应力层深度为小于等于180μm,内部张应力的最大值小于等于180Mpa,张应力线密度小于等于60000Mpa/mm,在室温和频率为1.8GHz下的介电损耗角正切小于或等于9×10~(-3)。该强化玻璃陶瓷是通过具有特殊的理化特征的原片玻璃进行微晶化热处理和离子交换处理后所获得的,且其强度足够其作为电子设备的前后保护盖。因其具有整体分布均匀的纳米晶体而具有很高的本征强度,化学强化实现低的表面压应力后仍然具有高的玻璃抗跌强度。因此,工业生产过程中,低CS值的该低强化玻璃陶瓷的强度受盐浴中垃圾离子Na~+、Li~+的含量变化以及大碱金属离子的分布的影响更小,保证最终大批量生产的强化玻璃陶瓷的强度均匀性较高。(The surface compressive stress of the strengthened glass ceramic is between 100 and 450MPa, the depth of a compressive stress layer is less than or equal to 180 mu m, the maximum value of the internal tensile stress is less than or equal to 180MPa, the linear density of the tensile stress is less than or equal to 60000MPa/mm, and the dielectric loss tangent at room temperature and the frequency of 1.8GHz is less than or equal to 9 multiplied by 10 ‑3 . The strengthened glass ceramic is obtained by carrying out microcrystallization heat treatment and ion exchange treatment on original glass with special physical and chemical characteristics, and has enough strength to be used as front and rear protective covers of electronic equipment. The glass has very high intrinsic strength due to the fact that the nano crystals are uniformly distributed on the whole, and the glass still has high glass drop strength after low surface compressive stress is achieved through chemical strengthening. Therefore, in the industrial production process, the strength of the low-strengthened glass ceramic with low CS value is influenced by the garbage ions Na in the salt bath + 、Li + The content change and the distribution of large alkali metal ions have smaller influence, and the strength uniformity of the strengthened glass ceramic produced in large batch is ensured to be higher.)
1. The strengthened glass ceramic with low surface compressive stress is characterized in that the surface compressive stress of the strengthened glass ceramic is between 100 and 450MPa, and the depth of a compressive stress layer is less than or equal to 180 mu m; the maximum value of the internal tensile stress of the strengthened glass ceramic is less than or equal to 180 Mpa; the tensile stress linear density of the strengthened glass ceramic is less than or equal to 60000Mpa/mm, and the dielectric loss tangent of the strengthened glass ceramic is less than or equal to 9 multiplied by 10 under the room temperature and the frequency of 1.8GHz-3。
2. The low surface compressive stress strengthened glass-ceramic of claim 1, wherein the surface compressive stress of the strengthened glass-ceramic is between 150-380 Mpa; the depth of the compressive stress layer of the strengthened glass ceramic is less than or equal to 150 mu m; the maximum value of the internal tensile stress of the strengthened glass ceramic is less than or equal to 160 Mpa; the tensile stress linear density of the strengthened glass ceramic is less than or equal to 40000Mpa/mm, and the dielectric loss tangent of the strengthened glass ceramic is less than or equal to 8 multiplied by 10 under the room temperature and the frequency of 1.8GHz-3。
3. The low surface compressive stress strengthened glass-ceramic of claim 2, wherein the surface compressive stress of the strengthened glass-ceramic is between 180 and 350 Mpa; the maximum value of the internal tensile stress of the strengthened glass ceramic is less than or equal to 140 Mpa; the linear density of the tensile stress of the strengthened glass ceramic is less than or equal to 34000 mpa/mm.
4. The low surface compressive stress strengthened glass of claim 1The glass-ceramic is characterized in that the strengthened glass-ceramic comprises a glass body and a plurality of crystals which are discretely distributed in the glass body, and the composition of the crystals is Li2-2(X+Y)·MgXZnYO·Al2O3·nSiO2Or/and Li2O·2SiO2Wherein n is between 2 and 10, X + Y is less than or equal to 1, the proportion of the crystals is between 20 and 80wt percent, the size of the crystals is between 6 and 80nm, and the average size of a plurality of crystals is less than or equal to 50 nm.
5. The low surface compressive stress strengthened glass-ceramic of claim 1, wherein the strengthened glass-ceramic comprises, in mole percent:
60-80% SiO2；
3-11% of Al2O3；
0.5-8% of P2O5And/or B2O3；
7-18% of Li2O；
0.05-2% of Na2O；
0.05-2% of K2O；
1-6% of ZrO2；
0-2% of TiO2；
0-1% of SnO2。
6. The low surface compressive stress strengthened glass ceramic of claim 5, further comprising 0 to 8 mol% of other oxides, the other oxides comprising MgO, ZnO, and Tm2O3One or more of (a).
7. The low surface compressive stress strengthened glass-ceramic of claim 5, wherein the strengthened glass-ceramic comprises, in mole percent:
68-75% of SiO2；
5-7 mol% of Al2O3；
2-7% of P2O5And/or B2O3；
7.5-15% Li2O；
0.05-1% of Na2O；
0.05-1% of K2O；
2-5% of ZrO2；
0-1% of TiO2；
0.1-0.5% SnO2。
8. The low surface compressive stress strengthened glass ceramic according to claim 1, wherein the young's modulus of the strengthened glass ceramic is 85GPa or greater; the equibiaxial flexural strength of the strengthened glass ceramic is more than or equal to 800N; the bending strength of the strengthened glass ceramic in the X-axis direction and the bending strength of the strengthened glass ceramic in the Y-axis direction are respectively more than or equal to 450MPa and 180 MPa.
9. The low surface compressive stress strengthened glass ceramic of claim 8, wherein the equibiaxial flexural strength of the strengthened glass ceramic is 1200N or greater.
10. The low surface compressive stress strengthened glass ceramic of claim 1, wherein the strengthened glass ceramic has an average visible light transmission of 90% or more and a haze of 0.2% or less.
11. A starting sheet glass, characterized in that it is subjected to a microcrystallization heat treatment and an ion exchange treatment to produce a strengthened glass ceramic according to any one of claims 1 to 10; the original sheet glass comprises the following components in percentage by mole:
60-80% SiO2；
3-11% of Al2O3；
0.5-8% of P2O5And/or B2O3；
7-18% of Li2O；
0-2% of Na2O；
0-2% of K2O；
1-6% of ZrO2；
0-2% of TiO2；
0-1% of SnO2。
12. The raw sheet glass according to claim 11, further comprising 0 to 8 mol% of other oxides including MgO, ZnO and Tm2O3One or more of (a).
13. The raw glass as claimed in claim 11, wherein the raw glass comprises, in mole percent:
68-75% of SiO2；
5-7% of Al2O3；
2-7% of P2O5And/or B2O3；
7.5-15% Li2O；
0-1% of Na2O；
0-1% of K2O；
2-5% of ZrO2；
0-1% of TiO2；
0.1-0.5% SnO2。
14. The raw sheet glass according to claim 11, wherein the raw sheet glass does not contain Na2O。
15. The original glass sheet according to claim 11, wherein the young's modulus of the original glass sheet is 80GPa or more.
16. The glass master according to claim 11, wherein the molar volume V of the glass mastermLess than or equal to 25.5cm3Mol, said molar volume being expressed as formula Vm＝∑xiMiRho, where xiAnd MiRespectively the mole fraction and the molar mass of each oxide composition, and rho is the density of the original sheet glass.
17. The raw sheet glass according to claim 11, wherein the microcrystallization heat treatment comprises a nucleation step and a crystallization step; the conditions of the nucleation process are as follows: the nucleation temperature is 580-750 ℃, and the heat preservation time is 0.5-5 h; the conditions of the crystallization process are as follows: the crystallization temperature is 700-800 ℃, and the heat preservation time is 0.5-5 h.
18. The sheet glass of claim 11, wherein the ion exchange treatment is one or more chemical strengthening in a mixed salt bath comprising at least two of potassium, sodium, and lithium salts, the potassium salt comprising KNO3And/or KCl, the sodium salt including NaNO3And/or NaNO2And said lithium salt comprises LiNO3And/or Li2CO3。
19. The raw sheet glass of claim 18, wherein the mixed salt bath comprises the potassium salt, the sodium salt, and the lithium salt.
20. The sheet glass of claim 18, wherein the mixed salt bath comprises NaNO3And LiNO3Wherein, NaNO35-75% of LiNO in the mixed salt bath3Accounting for 0.05-5% of the mass of the mixed salt bath.
21. The raw sheet glass according to claim 18, wherein the temperature of the mixed salt bath is 400 to 550 ℃, and the total time period of the ion exchange treatment is 5 hours or more.
Technical Field
The invention relates to the technical field of glass, in particular to a strengthened glass ceramic with low surface compressive stress and original glass.
Background
At present, glass is commonly used as a front cover and a rear cover protection material of electronic equipment (such as a smart phone, a portable computer, a tablet computer and the like). In order to make the whole mobile phone lighter and thinner, the glass used as the mobile phone protective cover plate is also thinner and thinner, and in order to make the light and thin glass reach sufficient strength, the existing strengthening means is usually a chemical strengthening method, specifically, large alkali metal ions in salt bath, such as potassium ions and sodium ions, exchange sodium ions and lithium ions in the glass under high temperature condition, finally, due to the exchange plasma accumulation effect, compressive stress is generated in the glass, so that tiny cracks/defects on the glass surface are difficult to grow, and the glass strength is increased. It is known that the process of industrially producing tempered glass is to place a large amount of glass in different batches in a same tempering furnace with salt bath for ion exchange, especially for high-sodium ion glass, and as the service time of the salt bath is prolonged and the amount of glass treated by the salt bath is increased, garbage ions Na in the salt bath+、Li+The content of the glass can be increased, although the glass is PPM-level, the content of the glass can also be enough to seriously hinder the normal chemical toughening, so that the CS value of the subsequent glass after being strengthened is reduced, the strength is greatly reduced, and the strengthened glass produced in different batches has uneven strength level, poor uniformity and high dispersion. In addition, even the strength of the strengthened glass produced in the same batch varies greatly depending on the uniformity of the distribution of the large alkali metal ions in the salt bath. This makes the final product quality difficult to manage. In order to reduce garbage ions Na in salt bath+、Li+Content variation and uniformity of distribution of large alkali metal ions of the glass composition are strong to the finally obtained strengthened glassThe influence of the uniformity and the dispersion of the degree, the dependence of industrial production of the strengthened glass on the chemical strengthening process needs to be reduced, that is, the strength of the glass cannot be improved by only relying on the chemical strengthening. On the other hand, with the advent of the age of 5G, 5G communication has also made higher demands on electronic devices, and ordinary glass is exposed to high-frequency or ultrahigh-frequency electromagnetic fields, which results in slow transmission speed, signal intensity attenuation and signal transmission time delay phenomena, thus requiring glass to have lower dielectric loss.
Disclosure of Invention
The present invention has been made to solve the above problems occurring in the prior art, and an object of the present invention is to provide a strengthened glass ceramic obtained by subjecting a starting sheet of glass having specific physicochemical characteristics to a microcrystallization heat treatment and an ion exchange treatment, and having a strength sufficient for use as front and rear protective covers of an electronic device. The strengthened glass ceramic has low sodium content on one hand and high intrinsic strength due to the overall uniformly distributed nanocrystals, and therefore has high glass drop strength even though the surface compressive stress obtained by chemical strengthening is low. Therefore, in the industrial production process, the strength of the strengthened glass ceramic with low CS value is subjected to the garbage ions Na in the salt bath+、Li+The content change and the distribution of large alkali metal ions have smaller influence, and the strength uniformity of the strengthened glass ceramic produced in large batch is ensured to be higher. In addition, the strengthened glass ceramic has low dielectric loss due to low sodium content, and meets the new requirements of the high-frequency electromagnetic field in the 5G era on the front and rear cover plates of the electronic equipment.
The technical scheme adopted by the invention for solving the technical problems is as follows: providing a strengthened glass ceramic with low surface compressive stress, wherein the surface compressive stress of the strengthened glass ceramic is between 100 and 450MPa, and the depth of a compressive stress layer is less than or equal to 180 mu m; the maximum value of the internal tensile stress of the strengthened glass ceramic is less than or equal to 180 Mpa; the tensile stress linear density of the strengthened glass ceramic is less than or equal to 60000Mpa/mm, and the strengthened glass ceramic is heated at room temperatureA dielectric loss tangent of 9 x 10 or less at a frequency of 1.8GHz-3。
As the low surface compressive stress strengthened glass ceramic, the surface compressive stress of the strengthened glass ceramic is between 200 and 350 MPa; the depth of the compressive stress layer of the strengthened glass ceramic is less than or equal to 150 mu m; the maximum value of the internal tensile stress of the strengthened glass ceramic is less than or equal to 150 Mpa; the tensile stress linear density of the strengthened glass ceramic is less than or equal to 40000Mpa/mm, and the dielectric loss tangent of the strengthened glass ceramic is less than or equal to 5 multiplied by 10 under the room temperature and the frequency of 1.8GHz-3。
As the low surface compressive stress strengthened glass ceramic, the surface compressive stress of the strengthened glass ceramic is between 200 and 300 MPa; the maximum value of the internal tensile stress of the strengthened glass ceramic is less than or equal to 130 Mpa; the reinforced glass ceramic has a tensile stress linear density of 34000mpa/mm or less, and a dielectric loss tangent of 3 x 10 or less at room temperature and a frequency of 1.8GHz-3。
As a preference of the low surface compressive stress strengthened glass ceramic of the present invention, the strengthened glass ceramic comprises a glass body and a plurality of crystals discretely distributed in the glass body, and the composition of the crystals is Li2-2(X+Y)·MgXZnYO·Al2O3·nSiO2Or/and Li2O·2SiO2Wherein n is between 2 and 10, X + Y is less than or equal to 1, the proportion of the crystals is between 20 and 80wt percent, the size of the crystals is between 6 and 80nm, and the average size of a plurality of crystals is less than or equal to 50 nm.
Preferably, the strengthened glass-ceramic with low surface compressive stress of the present invention comprises the following components in mole percent:
60-80% SiO2；
3-11% of Al2O3；
0.5-8% of P2O5And/or B2O3；
7-18% of Li2O；
0.05-2% of Na2O
0.05-2% of K2O
1-6% of ZrO2；
0-2% of TiO2；
0-1% of SnO2。
As a preferable aspect of the low surface compressive stress strengthened glass ceramic of the present invention, the strengthened glass ceramic further comprises 0 to 8 mol% of another oxide including MgO, ZnO and Tm2O3One or more of (a).
Preferably, the strengthened glass-ceramic with low surface compressive stress of the present invention comprises the following components in mole percent:
68-75% of SiO2；
5-7 mol% of Al2O3；
2-7% of P2O5And/or B2O3；
7.5-15% Li2O；
0.05-1% of Na2O；
0.05-1% of K2O；
2-5% of ZrO2；
0-1% of TiO2；
0.1-0.5% SnO2。
The low surface compressive stress strengthened glass ceramic of the present invention preferably has a Young's modulus of 85GPa or more; the equibiaxial flexural strength of the strengthened glass ceramic is more than or equal to 800N; the bending strength of the strengthened glass ceramic in the X-axis direction and the bending strength of the strengthened glass ceramic in the Y-axis direction are respectively more than or equal to 450MPa and 180 MPa.
The low surface compressive stress strengthened glass ceramic of the present invention preferably has an equibiaxial flexural strength of 1200N or more.
Preferably, the strengthened glass ceramic having a low surface compressive stress of the present invention has an average visible light transmittance of 90% or more and a haze of 0.2% or less.
The invention also provides the original glass, and the strengthened glass ceramic can be prepared from the original glass through micro crystallization heat treatment and ion exchange treatment; the original sheet glass comprises the following components in percentage by mole:
60-80% SiO2；
3-11% of Al2O3；
0.5-8% of P2O5And/or B2O3；
7-18% of Li2O；
0-2% of Na2O；
0-2% of K2O；
1-6% of ZrO2；
0-2% of TiO2；
0-1% of SnO2；
Preferably, the raw sheet glass provided by the invention further comprises 0-8 mol% of other oxides, wherein the other oxides comprise MgO, ZnO and Tm2O3One or more of (a).
As a preferable raw sheet glass provided by the present invention, the raw sheet glass contains the following components in mol%:
68-75% of SiO2；
5-7% of Al2O3；
2-7% of P2O5And/or B2O3；
7.5-15% Li2O
0-1% of Na2O
0-1% of K2O
2-5% of ZrO2；
0-1% of TiO2；
0.1-0.5% SnO2。
As a preferable aspect of the glass base sheet provided by the present invention, the base sheetThe flake glass does not contain Na2O。
Preferably, the raw glass of the present invention has a Young's modulus of 80GPa or more.
As the raw glass provided by the invention, the raw glass preferably has a molar volume VmLess than or equal to 25.5cm3Mol, said molar volume being expressed as formula Vm＝∑xiMiRho, where xiAnd MiRespectively the mole fraction and the molar mass of each oxide composition, and rho is the density of the original sheet glass.
Preferably, the glass starting sheet of the present invention is one wherein the microcrystallization heat treatment comprises a nucleation step and a crystallization step; the conditions of the nucleation process are as follows: the nucleation temperature is 580-750 ℃, and the heat preservation time is 0.5-5 h; the conditions of the crystallization process are as follows: the crystallization temperature is 700-800 ℃, and the heat preservation time is 0.5-5 h.
Preferably, the ion exchange treatment is one or more chemical strengthening in a mixed salt bath containing at least two of potassium salt, sodium salt and lithium salt, the potassium salt including KNO3And/or KCl, the sodium salt including NaNO3And/or NaNO2And said lithium salt comprises LiNO3And/or Li2CO3。
As a preferable aspect of the raw sheet glass provided by the present invention, the mixed salt bath contains the potassium salt, the sodium salt, and the lithium salt.
Preferably, the mixed salt bath contains NaNO as the raw sheet glass provided by the present invention3And LiNO3Wherein, NaNO35-75% of LiNO in the mixed salt bath3Accounting for 0.05-5% of the mass of the mixed salt bath.
As the optimization of the raw sheet glass provided by the invention, the temperature of the mixed salt bath is 400-550 ℃, and the total time of the ion exchange treatment is more than or equal to 5 hours.
Detailed Description
The surface of the strengthened glass ceramic provided by the invention has a through holeThe chemical ion exchange strengthens the resulting compressive stress layer. The surface compressive stress of the strengthened glass ceramic is between 100 and 450MPa, preferably between 200 and 350MPa, and more preferably between 200 and 300 MPa; the depth of the compressive stress layer is less than or equal to 180 μm, preferably less than or equal to 150 μm; the maximum value of the internal tensile stress of the strengthened glass ceramic is less than or equal to 180MPa, preferably less than or equal to 150MPa, and more preferably less than or equal to 130 MPa; the linear density of the tensile stress of the strengthened glass ceramic is less than or equal to 60000Mpa/mm, preferably less than or equal to 40000Mpa/mm, and more preferably less than or equal to 34000 Mpa/mm; the dielectric loss tangent of the strengthened glass ceramic is less than or equal to 8 multiplied by 10 under the room temperature and the frequency of 1.8GHz-3Preferably, it is 5X 10 or less-3More preferably, it is not more than 3X 10-3. The strengthened glass ceramic comprises a glass body and a plurality of crystals which are discretely distributed in the glass body, wherein the composition of the crystals is Li2-2(X+Y)·MgXZnYO·Al2O3·nSiO2Or/and Li2O·2SiO2Wherein n is between 2 and 10, X + Y is less than or equal to 1, the proportion of the crystals is between 20 and 80wt percent, the size of the crystals is between 6 and 80nm, and the average size of a plurality of crystals is less than or equal to 50 nm. The Young modulus of the strengthened glass ceramic is more than or equal to 85 GPa; equibiaxial flexural strength of 800N or more, preferably 1200N or more; the bending strength in the X axial direction and the bending strength in the Y axial direction are respectively more than or equal to 450Mpa and 180 Mpa; the average visible light transmittance is more than or equal to 90 percent; the haze is less than or equal to 0.2%.
The crystal composition, the size of the crystal, the internal tensile stress, the average visible light transmittance, the haze and the dielectric loss tangent are detected by adopting the conventional detection means in the industry.
The surface compressive stress CS (in MPa) and the depth of layer DOL (in μm) of the compressive stress of the strengthened glass ceramic were measured using a FSM-6000LE surface stress meter (Japan institute of atomic Power), and the resulting surface compressive stress was measured as the surface compressive stress produced by K-Na exchange.
The Young's modulus of the strengthened glass-ceramic is measured in GPa according to ASTM C-623.
The explanation for the tensile stress linear density is as follows: the strengthened glass ceramic is internally provided with a tensile stress layer formed in the ion exchange process, the tensile stress layer is provided with an upper boundary which has a certain interval with the upper surface of the strengthened glass ceramic and a lower boundary which has a certain interval with the lower surface of the strengthened glass ceramic, the tensile stress in the tensile stress layer, which is perpendicular to the upper boundary and the lower boundary at the same time and the upper end point and the lower end point of which respectively fall on a certain point on a line segment on the upper boundary and the lower boundary, is taken as a Y axis, and the distance between the corresponding point and the upper boundary is a curve drawn by an X axis and is recorded as a tensile stress curve, and the ratio of the fixed integral of the tensile stress curve to the thickness of the strengthened glass ceramic is recorded as the tensile stress linear density, namely the ratio of the sum of the tensile stresses at each point on the line segment of the strengthened glass ceramic measured by the SLP-1000 stress meter to the thickness of the strengthened glass ceramic.
Equibiaxial flexural strength was determined by ring-on-ring testing. The ring-on-ring test covers the determination of biaxial strength of advanced brittle materials under monotonic uniaxial loading via a concentric ring configuration. Such tests have been widely accepted and used to evaluate the surface strength of glass substrates. For the ring-on-ring experiment performed for embodiments herein, a 30mm diameter support ring and a 15mm diameter load ring may be employed on a sample size of about 2 inches by 2 inches. The contact radius of the ring may be about 1.6mm and the head speed may be about 1.2 mm/min.
And (3) performing a four-point bending test on the tempered glass ceramic according to ASTM D6272-02, wherein the lower span is 60.0mm, the upper span is 20.0mm, the displacement speed of a pressure head is 4.0mm/min, recording the pressure and the displacement of the pressure head, and calculating according to the size of the tempered glass ceramic to obtain the bending strength in the X axial direction and the bending strength in the Y axial direction.
The strengthened glass ceramic comprises the following components in percentage by mole: 60-80% SiO2(ii) a 3-11% of Al2O3(ii) a 0.5-8% of P2O5And/or B2O3(ii) a 7-18% of Li2O; 0.05-2% of Na2O; 0.05-2% of K2O; 1-6% of ZrO2(ii) a 0-2% of TiO2(ii) a 0-1% of SnO2. Preferably, the strengthened glass ceramic comprises the following components in percentage by mole: 68-75% of SiO2(ii) a 5-7 mol% of Al2O3(ii) a 2-7% of P2O5And/or B2O3(ii) a 7.5-15% Li2O; 0.05-1% of Na2O; 0.05-1% of K2O; 2-5% of ZrO2(ii) a 0-1% of TiO2(ii) a 0.1-0.5% SnO2. Optionally, the strengthened glass ceramic further comprises 0-8 mol% of other oxides, and the other oxides comprise MgO, ZnO and Tm2O3One or more of (a).
The preparation method of the strengthened glass ceramic comprises the step of carrying out microcrystallization heat treatment and ion exchange treatment on the original glass to obtain the strengthened glass ceramic.
The key of the preparation method is the physicochemical characteristics of the original glass. Specifically, the raw sheet glass comprises the following components in percentage by mole: 60-80% SiO2(ii) a 3-11% of Al2O3(ii) a 0.5-8% of P2O5And/or B2O3(ii) a 7-18% of Li2O; 0-2% of Na2O; 0-2% of K2O; 1-6% of ZrO2(ii) a 0-2% of TiO2(ii) a 0-1% of SnO2. Preferably, the base glass comprises 68-75% SiO2(ii) a 5-7% of Al2O3(ii) a 2-7% of P2O5And/or B2O3(ii) a 7.5-15% Li2O; 0-1% of Na2O; 0-1% of K2O; 2-5% of ZrO2(ii) a 0-1% of TiO2(ii) a 0.1-0.5% SnO2. Optionally, the raw sheet glass further comprises 0-8 mol% of other oxides, and the other oxides comprise MgO, ZnO and Tm2O3One or more of (a). Optionally, the raw sheet glass may further contain no Na2O。
The Young's modulus of the original glass sheet is greater than or equal to 80 GPa.
Molar volume V of the glass sheetmLess than or equal to 25.5cm3Mol, said molar volume being expressed as formula Vm＝∑xiMi/p, where xiAnd MiRespectively the mole fraction and the molar mass of each oxide composition, and rho is the density of the glass ceramic.
The microcrystallization heat treatment comprises a nucleation step and a crystallization step; the conditions of the nucleation process are as follows: the nucleation temperature is 580-750 ℃, and the heat preservation time is 0.5-5 h; the conditions of the crystallization process are as follows: the crystallization temperature is 700-800 ℃, and the heat preservation time is 0.5-5 h.
The nucleation process comprises the following specific steps: and heating the original glass sheet to the nucleation temperature of 580-750 ℃ at the speed of 0-10 ℃/min, and preserving the heat for 0.5-5 h.
The crystallization process comprises the following specific steps: and heating the original piece of glass to the crystallization temperature of 700-800 ℃ at the speed of 5-10 ℃/min, and preserving the heat for 0.5-5 h.
The ion exchange treatment is one or more chemical intensifications in a mixed salt bath containing at least two of potassium salt, sodium salt, and lithium salt, the potassium salt including KNO3And/or KCl, the sodium salt including NaNO3And/or NaNO2And said lithium salt comprises LiNO3And/or Li2CO3. Optionally, the mixed salt bath comprises the potassium salt, the sodium salt, and the lithium salt. Preferably, the temperature of the mixed salt bath is 400-550 ℃, and the total time of the ion exchange treatment is more than or equal to 5 hours. Optionally, the mixed salt bath comprises NaNO3And LiNO3Wherein, NaNO35-75% of LiNO in the mixed salt bath3Accounting for 0.05-5% of the mass of the mixed salt bath.
In order to more clearly understand the technical features, objects, and effects of the present invention, specific embodiments of the present invention will now be described in detail. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Examples 1 to 5: preparation of strengthened glass ceramic from raw sheet glass
In examples 1 to 5, lots (1000 pieces) of the virgin glass I, the virgin glass II, the virgin glass III, the virgin glass IV and the virgin glass V were subjected to the above-mentioned microcrystallization heat treatment and ion exchange treatment to prepare lots (1000 pieces) of the strengthened glass ceramic I, the strengthened glass ceramic II, the strengthened glass ceramic III, the strengthened glass ceramic IV and the strengthened glass ceramic V, respectively.
The physicochemical characteristics of the glass sheets I to V are shown in the following tables.
The parameters involved in the microcrystallization heat treatment and ion exchange treatment of the glass I, II, III, IV and V are shown in the following tables.
The composition of the crystal in the obtained strengthened glass ceramic I is Li1.8·Mg0.1O·Al2O3·6SiO2The maximum crystal size is 26nm, the minimum crystal size is 24nm, the average crystal size is 25nm, and the crystal ratio is 75% of the total mass of the strengthened glass ceramic I.
The physical and chemical characteristics of the batch of the thus-obtained strengthened glass ceramic I were examined, and the results are shown in the following Table.
Physical and chemical characteristics
Maximum value
Minimum value
Mean value of
Young's modulus/GPa
92.45
91.30
91.88
Equibiaxial flexural strength/N
1600
1508
1554
Bending strength in X-axis direction/MPa
820
780
800
Bending strength in Y-axis direction/MPa
400
380
390
Average visible light transmittance/%)
91.8
91.4
91.6
Haze/%
0.080
0.078
0.079
Dielectric loss tangent
0.00510
0.00500
0.00505
Surface compressive stress/MPa
418
406
412
Depth of compressive stress layer/. mu.m
176
166
163
Maximum value of internal tensile stress/Mpa
180
170
175
Tensile stress linear density/Mpa/mm
36366
36150
36258
As can be seen from the above table, the average value of the equibiaxial flexural strength of the batch of the tempered glass ceramic I is 1554N, and the difference between the maximum value and the minimum value is only 92N; the average value of the bending strength in the X axial direction is 800MPa, and the difference between the maximum value and the minimum value is only 40 MPa; the bending strength of the Y axis is 390 MPa; the difference between the maximum value and the minimum value is only 20MPa, which is enough to show that the I strength of the batch of the strengthened glass ceramic produced by the batch of the original glass I has higher uniformity and low dispersion.
The composition of the crystal in the obtained strengthened glass ceramic II is Li & Mg0.5O·Al2O3·8SiO2The maximum crystal size is 40nm, the minimum crystal size is 38nm, the average crystal size is 39nm, and the crystal ratio is 40% of the total mass of the strengthened glass ceramic II.
The physical and chemical characteristics of the batch of the thus-obtained strengthened glass ceramic II were examined, and the results are shown in the following table.
Physical and chemical characteristics
Maximum value
Minimum value
Mean value of
Young's modulus/GPa
88.60
88.40
88.50
Equibiaxial flexural strength/N
1500
1380
1440
Bending strength in X-axis direction/MPa
720
676
698
Bending strength in Y-axis direction/MPa
340
306
323
Average visible light transmittance/%)
91.4
91.2
91.3
Haze/%
0.098
0.096
0.097
Dielectric loss tangent
0.00820
0.00810
0.00815
Surface compressive stress/MPa
360
348
354
Depth of compressive stress layer/. mu.m
105
94
99.5
Maximum value of internal tensile stress/Mpa
142
130
136
Tensile stress linear density/Mpa/mm
29330
29020
29175
As can be seen from the above table, the average equibiaxial flexural strength of the batch of the tempered glass ceramic II is 1440N, and the difference between the maximum value and the minimum value is only 120N; the average value of the bending strength in the X axial direction is 698MPa, and the difference between the maximum value and the minimum value is only 44 MPa; the bending strength of the Y axial direction is 323 MPa; the difference between the maximum value and the minimum value is only 34MPa, which is enough to show that the strength uniformity of the batch of the strengthened glass ceramic produced by the batch of the original sheet glass II is higher.
The crystal composition in the obtained strengthened glass ceramic III mainly comprises Li2O·Al2O3·8SiO2And also includes a small amount of Li2O·2SiO2The maximum crystal size is 34nm, the minimum crystal size is 32nm, the average crystal size is 33nm, and the crystal ratio is 78% of the total mass of the strengthened glass ceramic III.
The physical and chemical characteristics of the batch of the thus-obtained strengthened glass ceramic III were examined, and the results are shown in the following table.
Physical and chemical characteristics
Maximum value
Minimum value
Mean value of
Young's modulus/GPa
90.12
90.08
90.10
Equibiaxial flexural strength/N
2120
2010
2065
Bending strength in X-axis direction/MPa
890
860
875
Bending strength in Y-axis direction/MPa
460
442
451
Average visible light transmittance/%)
91.5
91.4
91.45
Haze/%
0.092
0.090
0.091
Dielectric loss tangent
0.00240
0.00230
0.00235
Surface compressive stress/MPa
270
258
264
Depth of compressive stress layer/. mu.m
162
148
155
Maximum value of internal tensile stress/Mpa
158
144
151
Tensile stress linear density/Mpa/mm
51758
51554
51656
As can be seen from the above table, the average equibiaxial flexural strength of the batch of the obtained strengthened glass ceramics III is 2065N, and the difference between the maximum value and the minimum value is only 110N; the average value of the bending strength in the X axial direction is 875MPa, and the difference between the maximum value and the minimum value is only 30 MPa; the bending strength of the Y axis is 451 MPa; the difference between the maximum and minimum values is only 18MPa, which is sufficient to demonstrate the high strength uniformity of the I strength of batches of strengthened glass-ceramics produced from batches of pristine glass III.
The crystal composition in the prepared strengthened glass ceramic IV mainly comprises Li2O·2SiO2And also includes a small amount of Li1.4·Zn0.3O·Al2O3·8SiO2The size of the maximum crystal is 60nm, the size of the minimum crystal is 30nm, the average size of the crystals is 45nm, and the crystal ratio is 70% of the total mass of the strengthened glass ceramic IV.
The physical and chemical characteristics of the batch of the produced strengthened glass ceramics IV were examined, and the results are shown in the following table.
Physical and chemical characteristics
Maximum value
Minimum value
Mean value of
Young's modulus/GPa
86.66
86.60
86.63
Equibiaxial flexural strength/N
1220
1156
1188
Bending strength in X-axis direction/MPa
780
746
763
Bending strength in Y-axis direction/MPa
360
342
351
Average visible light transmittance/%)
90.8
90.6
90.7
Haze/%
0.140
0.136
0.138
Dielectric loss tangent
0.00470
0.00460
0.00465
Surface compressive stress/MPa
230
216
223
Depth of compressive stress layer/. mu.m
122
110
116
Maximum value of internal tensile stress/Mpa
136
124
130
Tensile stress linear density/Mpa/mm
38280
38070
38175
As can be seen from the above table, the average value of the equibiaxial flexural strength of the batch of the prepared strengthened glass ceramics IV is 1188N, and the difference between the maximum value and the minimum value is only 64N; the average value of the bending strength of the X axial direction is 763MPa, and the difference between the maximum value and the minimum value is only 34 MPa; the bending strength of the Y axis is 351 MPa; the difference between the maximum value and the minimum value is only 18MPa, which is enough to show that the IV strength uniformity of the batch of the strengthened glass ceramic produced by the batch of the original sheet glass IV is higher.
The crystal composition in the resulting strengthened glass-ceramic V mainly comprises Li2O·2SiO2And also includes a small amount of Li2O·Al2O3·10SiO2The maximum crystal size is 40nm, the minimum crystal size is 34nm, the average crystal size is 37nm, and the crystal ratio is 60% of the total mass of the strengthened glass ceramic V.
The physical and chemical characteristics of the batch of the thus-produced strengthened glass-ceramic V were examined, and the results are shown in the following table.
As can be seen from the above table, the average equibiaxial flexural strength of the batch of the obtained strengthened glass-ceramic V was 1620N, and the difference between the maximum value and the minimum value was only 80N; the average value of the bending strength in the X axial direction is 838MPa, and the difference between the maximum value and the minimum value is only 24 MPa; the bending strength of the Y axial direction is 373 MPa; the difference between the maximum value and the minimum value is only 14MPa, which is enough to show that the V strength uniformity of the batch of the strengthened glass ceramic produced by the batch of the original glass V is higher and the dispersion is low.
In summary, the batch of strengthened glass ceramics produced from the raw sheet glass provided by the present invention has the advantages of equal biaxial flexural strength, low dispersion of bending strength in the X-axis direction and bending strength in the Y-axis direction, and high uniformity. The reinforced glass produced by the existing glass generally has higher CS, and even if the reinforced glass is produced in the same batch, the extreme difference between the bending strength in the X-axis direction and the bending strength in the Y-axis direction can reach 300MPa, and the extreme difference between the biaxial flexural strength and the equivalent biaxial flexural strength can reach 1000N.
While embodiments of the present invention have been described, the present invention is not limited to the above-described embodiments, which are intended to be illustrative rather than limiting, and many modifications may be made by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.
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