WO2021068424A1 - Aluminosilicate glass, tempered glass, preparation method therefor, cover plate, back plate, and device - Google Patents

Abstract

Aluminosilicate glass, tempered glass, a preparation method therefor, a cover plate, a back plate, and a device. The aluminosilicate glass comprises, in mass percentage, 55-65% of SiO ₂, 13-26% of Al ₂O ₃, 2-6% of Li ₂O, 6-11% of Na ₂O, 1-6% of K ₂O, 0.1-3% of B ₂O ₃, and 0.1-4% of ZrO ₂. The aluminosilicate glass, after being chemically strengthened, exhibits excellent crushing resistance when falling on rough ground and good mechanical impact resistance.

Description

Aluminosilicate glass, strengthened glass and preparation method thereof, cover plate, back plate and device Technical field

The invention relates to the field of glass manufacturing, in particular to aluminosilicate glass, strengthened glass and a preparation method thereof, a cover plate, a back plate and a device.

Background technique

With the development of mobile Internet 5G communication technology and wireless charging technology, more and more electronic products have begun to use double-sided glass designs. For example, in pursuit of differentiated and personalized design concepts such as thinness and narrow bezels, more and more mobile phones adopt 3D curved glass cover or back panel designs.

When the glass produced by traditional technology is subjected to performance tests such as the whole machine drop test on rough (sandpaper) ground and the whole machine drum test, most of the performance and the stability of the data results are not ideal, especially the drop height of the smooth ground. In comparison, the drop and breakage height of rough ground is attenuated by more than 40%.

Aiming at the problem that the performance and stability of data results are mostly not ideal when the glass is subjected to performance tests such as a rough (sandpaper) ground machine drop test and a machine drum test. In recent years, two types of glass with better drop resistance have appeared. One type is high-alumina glass prepared by a one-step ion exchange chemical strengthening process, and the other is a glass prepared through a two-step or multi-step ion exchange chemical strengthening process.

Due to the high content of alumina, high alumina glass has higher strength than ordinary soda lime glass. At the same time, the ion exchange capacity of high alumina glass is also stronger. It is mainly used for protective cover plates and protective patch glass of electronic products. Visible light transmittance. ^{The current high-alumina glass is subjected to ion exchange for 2h-8h in pure potassium nitrate molten salt (Na +} concentration in the molten salt is controlled within 4000ppm) at a temperature of 390℃～450℃, the surface compressive stress (CS) generally reaches 650MPa Above, the depth of surface compressive stress (DOL) is above 30μm. When the ion exchange time is more than 7h, the depth of the surface compressive stress layer can be increased to about 60μm, but it is still far less than 80μm, and the surface compressive stress value is correspondingly reduced, which will easily lead to the formation of the strengthened glass surface and it is difficult to remove The alkali-rich layer, which in turn forms microcrack defects, seriously affects the overall strength of the glass.

The glass prepared by the two-step or multi-step ion exchange chemical strengthening process mainly introduces Li ₂ O into the composition of the glass, and the two-step or multi-step ion exchange chemical strengthening process is carried out. By controlling the first and The difference in the concentration of the molten salt in the second step is to complete the ion exchange of Li-Na and Na-K respectively to obtain a higher surface compressive stress layer depth and a better surface compressive stress value. At present, the glass prepared by a two-step or multi-step ion exchange chemical strengthening process can achieve a surface compressive stress layer depth greater than 80 μm and a surface compressive stress value greater than 600 MPa. However, the two-step or multi-step ion exchange chemical strengthening process is difficult to control the overall process time within 5 hours in practical applications, and the problem of molten salt pollution is prone to occur.

Summary of the invention

Based on this, it is necessary to provide a method for preparing strengthened glass with strong drop resistance, short time-consuming, and less likely to be polluted by molten salt.

In addition, an aluminosilicate glass for preparing strengthened glass with strong drop resistance and a strengthened glass with strong drop resistance, a cover plate, a back plate and a device are also provided.

An aluminosilicate glass, in terms of mass percentage, comprising 55%-65% SiO ₂ , 13%-26% Al ₂ O ₃ , 2%-6% Li ₂ O, 6%-11 % Na ₂ O, 1% to 6% K ₂ O, 0.1% to 3% B ₂ O ₃ and 0.1% to 4% ZrO ₂ .

A method for preparing strengthened glass includes the following steps:

The above-mentioned aluminosilicate glass is immersed in molten salt for ion exchange to obtain strengthened glass; wherein, the molten salt includes NaNO ₃ and KNO ₃ , and in the ion exchange, the Li ^{+ of the} aluminosilicate glass and the ratio of molten salt Na ⁺ Na exchange rate and the aluminosilicate glass with the molten salt ⁺ K ⁺ exchange rate of 4.8 to 6.3.

A strengthened glass prepared by the above-mentioned method for preparing strengthened glass.

A cover plate includes the above-mentioned strengthened glass.

A back plate includes the above-mentioned strengthened glass.

A device includes the above-mentioned strengthened glass.

The details of one or more embodiments of the present invention are set forth in the following description. Other features, objects and advantages of the present invention will become apparent from the description and claims.

Detailed ways

In order to facilitate the understanding of the present invention, the present invention will be described more fully below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field of the present invention. The terms used in the description of the present invention herein are only for the purpose of describing specific embodiments, and are not intended to limit the present invention.

According to an embodiment of the aluminosilicate glass, after the aluminosilicate glass is chemically strengthened, it satisfies: the depth of the surface compressive stress layer is not less than 75 μm; the surface compressive stress value is between 650 MPa and 900 MPa; the aluminum with a thickness of 0.5 mm The intermediate tensile stress of silicate glass is not higher than 80 MPa; the intermediate tensile stress of the aluminosilicate glass with a thickness of 0.7 mm is not higher than 60 MPa. After being chemically strengthened, the aluminosilicate glass has better anti-rough ground drop and breakage performance and better mechanical impact resistance. In addition, the glass transition temperature of the aluminosilicate glass is not less than 515°C, and the surface micro Vickers hardness is not less than 630HV.

Specifically, in terms of mass percentage, the aluminosilicate glass includes 55%-65% SiO ₂ , 13%-26% Al ₂ O ₃ , 2%-6% Li ₂ O, 6%- 11% Na ₂ O, 1% to 6% K ₂ O, 0.1% to 3% B ₂ O _3, and 0.1% to 4% ZrO ₂ .

Silicon dioxide (SiO ₂ ) is an essential component for forming the skeleton of aluminosilicate glass. SiO ₂ can improve the strength and chemical stability of aluminosilicate glass; SiO ₂ can make aluminosilicate glass obtain a higher strain point and a lower coefficient of thermal expansion. The mass percentage of SiO ₂ is 55%-65%. When _{the mass percentage of SiO 2} is less than 55%, the formed aluminosilicate glass has a poor main network structure, poor mechanical properties and poor weather resistance. When _{the mass percentage of SiO 2} exceeds 65%, the melting temperature in the production process of aluminosilicate glass will increase correspondingly, which will increase energy consumption and cause frequent bubbles, stones and other defects; and, due to SiO _{The mass percentage of 2} exceeds 65%, the proportion of silicon-oxygen skeleton structure is too high, and the network gap is small, which is not conducive to ion exchange in the chemical strengthening process and affects the efficiency of chemical strengthening. Further, _{the mass percentage content of SiO 2} is 58% to 63%.

Alumina (Al ₂ O ₃ ) is a necessary component to increase the ion exchange capacity of aluminosilicate glass, and at the same time it can improve the chemical stability of the glass. Due to _{the difference in Al 2} O ₃ content, the volume of the network space formed by the prepared aluminosilicate glass will vary. The _{higher the content of Al 2} O ₃ , the larger the gap of the framework network of aluminosilicate glass, which is more conducive to ion exchange; however, the thermal expansion coefficient of aluminosilicate glass will not be further reduced due to the excessively high content of _{Al 2} O ₃ , But the high-temperature viscosity of aluminosilicate glass has increased significantly, the melting temperature has also increased, and the energy consumption has increased correspondingly. It is also prone to defects such as bubbles and stones. However, when the Al ₂ O ₃ content of the aluminosilicate glass is low, the voids in the network space of the aluminosilicate glass become smaller, which is not conducive to ion migration and affects the efficiency of chemical strengthening. Therefore, _{the mass percentage of Al 2} O ₃ is 13% to 26%. Further, _{the mass percentage of Al 2} O ₃ is 16%-24%. Furthermore, _{the mass percentage of Al 2} O ₃ is 19%-22%.

Lithium oxide (Li ₂ O) is a flux and is an essential component for the chemical strengthening process for preparing strengthened glass in this embodiment. Due to ^{the polarization characteristics of Li +} , it can effectively reduce the high temperature viscosity at high temperatures. The molten salt used in the chemical strengthening process for preparing strengthened glass of this embodiment includes NaNO ₃ and KNO ₃ . Through the ^{ion exchange between Li + in the aluminosilicate glass and Na +} in the molten salt, the depth of the surface compressive stress layer can be increased in a short time, so that the glass has more excellent mechanical impact resistance. The mass percentage of Li ₂ O is 2% to 6%. When _{the mass percentage of Li 2} O is less than 2%, it is difficult for the aluminosilicate glass to obtain a higher surface compressive stress layer depth; when _{the mass percentage of Li 2} O is higher than 6%, the manufacturing cost increases. In addition, the expansion coefficient of glass is significantly increased, the tendency of glass to crystallize is too high, and the probability of generating stone defects is significantly increased. Further, _{the mass percentage of Li 2} O is 3% to 5.5%.

Sodium oxide (Na ₂ O) is another flux, which can significantly reduce the melting temperature of aluminosilicate glass and is also an essential component for ion exchange. The mass percentage of Na ₂ O is 6% to 11%. When the mass percentage content is less than 6%, not only the melting performance of the aluminosilicate glass is deteriorated, but also the stress value of the K-Na ion exchange layer formed by the strengthened aluminosilicate glass is too small. The shallow depth and the low CS value of the superficial layer will easily lead to poor micro-hardness and cracks, which will lead to a decline in the drop resistance of the corresponding products. When _{the mass percentage content of Na 2} O is higher than 11%, the aluminosilicate glass network structure is poor, the stability of mechanical properties and thermal properties is reduced, and the chemical durability is poor. Further, _{the mass percentage content of Na 2} O is 7%-10%.

Potassium oxide (K ₂ O) can improve the melting performance of aluminosilicate glass. K ₂ O, Li ₂ O and Na ₂ O can form a mixed alkali effect, which can reduce the high temperature viscosity of aluminosilicate glass. The mass percentage of K ₂ O is 1% to 6%. When _{the mass percentage of K 2} O is less than 1%, the stress depth of the K-Na ion exchange layer formed by the chemically strengthened aluminosilicate glass is very shallow, which is not conducive to the inward K+ ions during the ion exchange process Layer migration. When _{the mass percentage content of K 2} O is higher than 6%, the network structure of the aluminosilicate glass becomes worse, the stability of thermal properties is reduced, and the weather resistance becomes worse. Further, _{the mass percentage of K 2} O is 2.5%-4%.

Zirconia (ZrO ₂ ) can improve the chemical stability and ion exchange performance of aluminosilicate glass, increase the surface hardness of aluminosilicate glass, and increase the pressure required to form cracks in aluminosilicate glass, thereby making aluminum Silicate glass is more resistant to scratches and more resistant to drops. Only a small amount of ZrO ₂ can meet the requirements, and _{too much ZrO 2} will significantly increase the melting temperature of the aluminosilicate glass and cause defects such as stones. Therefore, in this embodiment, _{the mass percentage of ZrO 2} is 0.1% to 4%. Further, _{the mass percentage of ZrO 2} is 0.1% to 4%.

In one of the embodiments, _{the mass percentage of SiO 2} in the aluminosilicate glass is 58%-63%; and/or

The mass percentage of Al ₂ O ₃ in the aluminosilicate glass is 16%-24%; and/or

The mass percentage of Li ₂ O in the aluminosilicate glass is 3% to 5.5%; and/or

The mass percentage of Na ₂ O in the aluminosilicate glass is 7%-10%; and/or

The mass percentage of K ₂ O in the aluminosilicate glass is 2.5%-4%; and/or

The mass percentage of B ₂ O ₃ in the aluminosilicate glass is 0.1% to 3%; and/or

The mass percentage of ZrO ₂ in the aluminosilicate glass is 0.1%-4%.

Further, the _{mass percentage of Al 2} O ₃ in the aluminosilicate glass is 19%-22%.

In one of the embodiments, the above-mentioned aluminosilicate glass further includes MgO with a content of not more than 4% in terms of mass percentage. Magnesium oxide (MgO) can reduce the viscosity of aluminosilicate glass at high temperature, promote the melting and clarification of aluminosilicate glass, and can enhance the network space stability of aluminosilicate glass at low temperature, and can reduce it to a certain extent. The thermal expansion coefficient of aluminosilicate glass, but MgO hinders the ion exchange of the chemical strengthening process. It should be noted that the high temperature in this article refers to a temperature higher than 1400°C; when the temperature is higher than 1400°C, the glass melts. The low temperature in this article means that the temperature is lower than 800°C; when the temperature is lower than 800°C, it is convenient for the glass to undergo glass transition and annealing. Therefore, the mass percentage of MgO does not exceed 4%. When the mass percentage of MgO exceeds 4%, Mg ²⁺ seriously hinders the ion exchange capacity of the aluminosilicate glass, which in turn leads to a significant reduction in the depth of the surface compressive stress layer. Further, the mass percentage of MgO is 1% to 3%.

In one of the embodiments, the aluminosilicate glass includes 55%-65% SiO ₂ , 13%-26% Al ₂ O ₃ , and 2%-6% Li ₂ O in terms of mass percentage. , 6%-11% Na ₂ O, 1%-6% K ₂ O, 0.1%-3% B ₂ O ₃ , 0.1%-4% ZrO ₂ and not more than 4% MgO.

Furthermore, the aluminosilicate glass includes 58% to 63% of SiO ₂ , 16% to 24% of Al ₂ O ₃ , 3% to 5.5% of Li ₂ O, and 7% to 10% of Na ₂ O , 2.5% to 4% K ₂ O, 0.1% to 3% B ₂ O ₃ , 0.1% to 4% ZrO ₂ and 1% to 3% MgO.

In one of the embodiments, the aluminosilicate glass further includes ZnO with a content of not more than 3% in terms of mass percentage. ZnO can enhance the network stability of aluminosilicate glass at low temperature, but ZnO also has a significant hindrance to ion exchange. Therefore, the mass percentage of ZnO does not exceed 3%.

In one of the embodiments, the aluminosilicate glass includes 55%-65% SiO ₂ , 13%-26% Al ₂ O ₃ , and 2%-6% Li ₂ O in terms of mass percentage. , 6% to 11% of Na ₂ O, 1% to 6% of K ₂ O, 0.1% to 3% of B ₂ O ₃ , 0.1% to 4% of ZrO ₂ and no more than 3% of ZnO.

In one of the embodiments, the aluminosilicate glass includes 55%-65% SiO ₂ , 13%-26% Al ₂ O ₃ , and 2%-6% Li ₂ O in terms of mass percentage. , 6%～11% Na ₂ O, 1%～6% K ₂ O, 0.1%～3% B ₂ O ₃ , 0.1%～4% ZrO ₂ , no more than 4% MgO and no more than的3％ZnO. Further, the aluminosilicate glass includes 58% to 63% of SiO ₂ , 16% to 24% of Al ₂ O ₃ , 3% to 5.5% of Li ₂ O, 7% to 10% of Na ₂ O, 2.5% to 4% of K ₂ O, 0.1% to 3% of B ₂ O ₃ , 0.1% to 4% of ZrO ₂ , 1% to 3% of MgO, and no more than 1.5% of ZnO.

In one of the embodiments, the above-mentioned aluminosilicate glass further includes P ₂ O _{5 with a} content of not more than 3% in terms of mass percentage. Generally, when _{the content of Al 2} O ₃ is low, P ₂ O _{5 is} introduced, and P ₂ O ₅ enters the aluminosilicate glass network, making the network void larger than the alumino-oxytetrahedron, which can significantly increase the ion exchange capacity. More importantly, _{the introduction of P 2} O ₅ can further increase the strain point of the glass, which can slow down the stress relaxation problem in the ion exchange process to a certain extent, and achieve a higher level of surface compressive stress after strengthening. However, the _{introduction of too much P 2} O ₅ significantly increases the coefficient of thermal expansion, which in turn leads to a decrease in the surface compressive stress value. Therefore, _{the mass percentage content of P 2} O ₅ does not exceed 3%. Further, _{the mass percentage content of P 2} O ₅ does not exceed 1%.

In one of the embodiments, the aluminosilicate glass includes 55%-65% SiO ₂ , 13%-26% Al ₂ O ₃ , and 2%-6% Li ₂ O in terms of mass percentage. , 6%～11% Na ₂ O, 1%～6% K ₂ O, 0.1%～3% B ₂ O ₃ , 0.1%～4% ZrO ₂ and no more than 3% P ₂ O ₅ . Further, the aluminosilicate glass includes 58% to 63% of SiO ₂ , 16% to 24% of Al ₂ O ₃ , 3% to 5.5% of Li ₂ O, 7% to 10% of Na ₂ O, 2.5% to 4% K ₂ O, 0.1% to 3% B ₂ O ₃ , 0.1% to 4% ZrO ₂ and no more than 3% P ₂ O ₅ .

In one of the embodiments, the aluminosilicate glass includes 55%-65% SiO ₂ , 13%-26% Al ₂ O ₃ , and 2%-6% Li ₂ O in terms of mass percentage. , 6%～11% Na ₂ O, 1%～6% K ₂ O, 0.1%～3% B ₂ O ₃ , 0.1%～4% ZrO ₂ , no more than 4% MgO and no more than 3% P ₂ O ₅ . Further, the aluminosilicate glass includes 58% to 63% of SiO ₂ , 16% to 24% of Al ₂ O ₃ , 3% to 5.5% of Li ₂ O, 7% to 10% of Na ₂ O, 2.5% to 4% of K ₂ O, 0.1% to 3% of B ₂ O ₃ , 0.1% to 4% of ZrO _2, no more than 3% of P ₂ O ₅ and 1% to 3% of MgO.

In one of the embodiments, the aluminosilicate glass includes 55%-65% SiO ₂ , 13%-26% Al ₂ O ₃ , and 2%-6% Li ₂ O in terms of mass percentage. , 6%～11% Na ₂ O, 1%～6% K ₂ O, 0.1%～3% B ₂ O ₃ , 0.1%～4% ZrO ₂ , no more than 3% ZnO and no More than 3% P ₂ O ₅ . Further, the aluminosilicate glass includes 58% to 63% of SiO ₂ , 16% to 24% of Al ₂ O ₃ , 3% to 5.5% of Li ₂ O, 7% to 10% of Na ₂ O, 2.5% to 4% of K ₂ O, 0.1% to 3% of B ₂ O ₃ , 0.1% to 4% of ZrO ₂ , no more than 1.5% of ZnO, and no more than 1% of P ₂ O ₅ .

In one of the embodiments, the aluminosilicate glass includes 55%-65% SiO ₂ , 13%-26% Al ₂ O ₃ , and 2%-6% Li ₂ O in terms of mass percentage. , 6%～11% Na ₂ O, 1%～6% K ₂ O, 0.1%～3% B ₂ O ₃ , 0.1%～4% ZrO ₂ , no more than 4% MgO, no more than 3% ZnO and no more than 3% P ₂ O ₅ . Further, the aluminosilicate glass includes 58% to 63% of SiO ₂ , 16% to 24% of Al ₂ O ₃ , 3% to 5.5% of Li ₂ O, 7% to 10% of Na ₂ O, 2.5%～4% K ₂ O, 0.1%～3% B ₂ O ₃ , 0.1%～4% ZrO ₂ , 1%～3% MgO, no more than 1.5% ZnO and no more than 1%的P ₂ O ₅ .

In one of the embodiments, _{the mass percentage of SiO 2} in the aluminosilicate glass is 58%-63%; and/or

The mass percentage of Al ₂ O ₃ in the aluminosilicate glass is 16%-24%; and/or

The mass percentage of Li ₂ O in the aluminosilicate glass is 3% to 5.5%; and/or

The mass percentage of Na ₂ O in the aluminosilicate glass is 7%-10%; and/or

The mass percentage of K ₂ O in the aluminosilicate glass is 2.5%-4%; and/or

The mass percentage of B ₂ O ₃ in the aluminosilicate glass is 0.1% to 3%; and/or

The mass percentage of ZrO ₂ in the aluminosilicate glass is 0.1% to 4%; and/or

The mass percentage of MgO in the aluminosilicate glass is 1% to 3%; and/or

The mass percentage of ZnO in the above-mentioned aluminosilicate glass does not exceed 1.5%; and/or

The mass percentage content of P ₂ O ₅ in the aluminosilicate glass does not exceed 1%.

According to an embodiment of a method for preparing strengthened glass, the method includes step S110 to step S160.

Step S110: Prepare aluminosilicate glass, wherein the aluminosilicate glass is the aluminosilicate glass of any of the above embodiments.

Specifically, the steps of preparing aluminosilicate glass include: mixing the raw materials for preparing the above-mentioned silicate glass with a glass fining agent, and then melting them at a temperature of 1600°C to 1680°C to obtain molten glass; Forming, followed by annealing at 550°C to 650°C, to obtain the above-mentioned silicate glass.

Further, the melting temperature is 1650°C to 1680°C. Melting at 1650°C to 1680°C can make the glass achieve a better state of clarification and homogenization. The annealing temperature is 600°C to 650°C. Annealing at 600°C to 650°C can eliminate residual stress in the glass in a shorter time.

In this embodiment, the aluminosilicate glass is in the shape of a plate; the thickness of the aluminosilicate glass is 0.5 mm to 2 mm; the size of the aluminosilicate glass is 4 inches to 20 inches. Of course, in other embodiments, the size and thickness of the aluminosilicate glass can be adjusted according to actual needs.

Step S120, polishing the aluminosilicate glass.

Specifically, the surface flatness of the polished aluminosilicate glass does not exceed 0.01 mm.

In this embodiment, the surface of the aluminosilicate glass is polished using a disk brush combined with cerium oxide polishing powder. Of course, polishing is not limited to the use of disc brushes, and other polishing tools commonly used in the industry can also be used. The polishing powder is not limited to cerium oxide, and can also be other polishing powders commonly used in the industry. It should be noted that if the surface of the aluminosilicate glass is smooth and clean, and the surface flatness reaches 0.01 mm, for example, the aluminosilicate glass is float glass, the surface does not need to be polished, and step S120 can be omitted.

Step S130, performing hot bending treatment on the aluminosilicate glass.

In this embodiment, the aluminosilicate glass is placed in a hot bending machine, and after preheating, pressing and cooling, the flat aluminosilicate glass is formed into curved glass, thereby completing the hot bending process. Of course, the aluminosilicate glass can be processed in a manner commonly used in the industry to obtain curved aluminosilicate glass. It should be noted that if there is no need to process the aluminosilicate glass into curved glass, no hot bending treatment is needed, and step S130 can be omitted.

Step S140, cleaning the aluminosilicate glass.

In this embodiment, when cleaning the aluminosilicate glass, deionized water is used in combination with a rolling brush for cleaning. Of course, in other embodiments, other cleaning agents such as ethanol and acetone can also be used for cleaning, and it is not limited to using a roller brush for cleaning, and other tools can also be used for cleaning. Dry the aluminosilicate glass after cleaning. It should be noted that if the surface of the aluminosilicate glass is relatively clean, it does not need to be cleaned, and step S140 can be omitted.

Step S150, immersing the aluminosilicate glass in molten salt for ion exchange to obtain strengthened glass.

Specifically, the molten salt includes NaNO ₃ and KNO ₃ . Ion-exchange process, the ratio of aluminosilicate glass Na Li ⁺ and Na ⁺ in the molten salt, and the exchange rate of the aluminosilicate glass with the molten salt ⁺ K ⁺ exchange rate of 4.8 to 6.3. Further, the ratio of aluminosilicate glass Na Li ⁺ and Na ⁺ in the molten salt, and the exchange rate of the aluminosilicate glass with the molten salt ⁺ K ⁺ exchange rate of 5.5 to 6.3.

Specifically, the molten salt includes NaNO ₃ and KNO ₃ . The ion exchange rate between pure potassium nitrate molten salt and glass is too fast, which easily causes a large amount of K ⁺ to enter the glass in a short time. The K ⁺ accumulates on the shallow surface of the glass and is not easy to migrate further inward. At the same time, it blocks the passage of ions, resulting in Ion exchange cannot continue. Therefore, it is not easy to achieve good ion exchange effects with pure potassium nitrate molten salt. In this embodiment, the Li-Na ion exchange rate and the Na-K ion exchange rate are controlled _{by controlling the ratio of KNO 3} to NaNO _3.

Further, in terms of mass percentage, the molten salt includes 5% to 25% of NaNO ₃ and 75% to 95% of KNO ₃ . When _{the mass percentage of NaNO 3} is less than 5%, the ion exchange rate of Li-Na is slow, and ^{the surface enrichment of K +} is prone to block the ion exchange of Li-Na; when the mass percentage of _{NaNO 3} When it is higher than 25%, the Na-K ion exchange efficiency will decrease, which easily prevents the formation of high surface compressive stress on the surface of the aluminosilicate glass. Still further, the molten salt comprises 5% to 10% NaNO ₃ and 90% to 95% KNO _3.

In the traditional two-step or multi-step ion exchange chemical strengthening process, the molten salt generally uses pure KNO ₃ or _{a mixed molten salt of KNO 3} and NaNO ₃ , but after a period of use, the concentration of these molten salts will vary significantly. . Taking ^{the change of Na +} concentration as a reference, ^{the change range of Na +} concentration is generally controlled within 6000ppm, and more strictly controlled within 4000ppm. Once ^{the deviation of Na +} concentration in molten salt exceeds this range, the enhanced performance cannot be guaranteed, resulting in The processing yield is low. Therefore, in the actual preparation process, it is necessary to frequently replace the molten salt to meet the processing yield, but the frequent replacement of the molten salt will affect the production efficiency and increase the production cost. The preparation method of the strengthened glass of this embodiment adopts the above-mentioned aluminosilicate glass and controls the conditions of ion exchange, so that ^{the concentration of Na +} in the molten salt can fluctuate in the range of 2%, and the CS value fluctuates in the strengthening performance. The range is within 2.5%, and the fluctuation range of DOL is within 1%. ^{In other words, the change value of the Na +} concentration of the molten salt used for ion exchange in this embodiment can be 20000 ppm, which greatly prolongs the service life of the molten salt, improves production efficiency and processing yield, and reduces production costs.

Specifically, the temperature of ion exchange is 390°C to 460°C. When the ion exchange temperature is lower than 390°C, the ion exchange rate is slow, and the strengthening time needs to be increased to obtain acceptable mechanical properties. When the ion exchange temperature is higher than 460°C, stress relaxation is likely to occur and cause CS to drop. Under the premise that the depth of the surface compressive stress layer meets the requirements, it is difficult to obtain a larger CS value, and high strengthening temperature is likely to cause warpage, self-exposure and other problems that affect yield. Further, the temperature of ion exchange is 410°C to 440°C.

Specifically, the time of ion exchange is 180 min to 300 min. Due to the adjustment of the ion exchange rate, when the ion exchange time is less than 180 minutes, the degree of ion exchange is insufficient, and the CS and DOL values cannot reach expectations. When the ion exchange time is higher than 300min, there is no strong effect on the improvement of CS, and the increase of DOL value is of little practical significance and causes an increase in production costs. Further, the time of ion exchange is 210 min to 270 min.

In one embodiment, the molten salt comprises 5% to 25% NaNO ₃ and 75% to 95% KNO _3, the temperature of the ion exchange is 390 ℃ ~ 460 ℃, the ion exchange time is 180min ~ 300min. Under the condition that the molten salt contains 5%～25% NaNO ₃ and 75%～95% KNO ₃ , the ion exchange temperature is 390℃～460℃, and the ion exchange time is 180min～300min, the aluminosilicate glass The depth of ion exchange is not less than 75μm, and the surface compressive stress value is between 650～900MPa. Further, the molten salt comprises 5% to 10% NaNO ₃ and 90% to 95% KNO _3, the temperature of the ion exchange is 410 ℃ ~ 440 ℃, the ion exchange time is 210min ~ 270min.

Step S160, removing the molten salt on the surface of the strengthened glass.

Specifically, the strengthened glass is taken out of the molten salt and placed in a preheating furnace at a temperature of 390°C to 460°C, the power of the preheating furnace is turned off, and the furnace is cooled to room temperature and then placed in water for ultrasonic cleaning to remove the surface of the strengthened glass. Residual molten salt. In this embodiment, the ultrasonic cleaning time is 0.5 hour to 1 hour. Further, the water temperature for ultrasonic cleaning is 16°C-100°C.

The above-mentioned preparation method of strengthened glass has at least the following advantages:

(1) The strengthened glass prepared according to the above-mentioned strengthened glass preparation method has more excellent resistance to falling and breaking on rough ground: the above-mentioned strengthened glass preparation method involves simultaneous Li-Na ion exchange and Na-K ion exchange, and The ratio of the exchange rate of Li-Na ion exchange to that of Na-K ion exchange is controlled to be 4.8-6.3, so that the surface compressive stress layer formed by aluminosilicate glass is a composite compressive stress layer. The layers include a Na-K ion exchange layer near the surface of the glass and a Li-Na ion exchange layer near the inner layer of the glass. The depth of the surface compressive stress layer of the strengthened glass prepared according to the above-mentioned method for preparing strengthened glass is not less than 75 μm, and the surface compressive stress value is not less than 650 MPa. Therefore, the strengthened glass prepared according to the above-mentioned method for preparing strengthened glass has more excellent anti-rough ground drop and breakage performance, and higher anti-drop performance.

(2) The strengthened glass prepared according to the above-mentioned strengthened glass preparation method has better mechanical impact resistance: when the intermediate tensile stress formed inside the glass is greater than 110 MPa, it is easy to explode, especially the glass with a thickness of less than 0.5 mm. In the traditional chemical strengthening process, the intermediate tensile stress formed inside the glass is generally greater than 110 MPa, so it is prone to self-explosion, and due to the large intermediate tensile stress inside the glass, it is easy to induce the crack propagation of micro-cracks on the glass surface. Therefore, when impacted by an external force, the glass strengthened by the traditional chemical strengthening process is more prone to breakage, and the drop and breakage resistance on rough ground is significantly lower. The intermediate tensile stress of the strengthened glass with a thickness of 0.5 mm prepared according to the above-mentioned method for preparing strengthened glass is not higher than 80 MPa, and the intermediate tensile stress of the strengthened glass with a thickness of 0.7 mm is not higher than 60 MPa. Therefore, compared with the traditional chemical strengthening process, the strengthened glass prepared according to the above-mentioned strengthened glass preparation method has better mechanical impact resistance and higher drop resistance.

(3) The above-mentioned method for preparing strengthened glass has a shorter period of time for preparing strengthened glass: when the traditional one-step ion exchange chemical strengthening process is used to prepare high-alumina glass with a surface compressive stress layer depth of 60μm or more, the ion exchange time needs to be more than 420min. Moreover, the depth of the stress layer of the strengthened glass prepared by the traditional one-step ion exchange chemical strengthening process is difficult to reach 80 μm. When a two-step or multi-step ion exchange chemical strengthening process is used, although it is possible to prepare strengthened glass with a surface compressive stress layer greater than 80 μm and a surface compressive stress value higher than 600 MPa, two or more steps of ion exchange chemical strengthening The process is difficult to control the time of ion exchange within 300 minutes. The use of the above-mentioned method for preparing strengthened glass can control the ion exchange time to 300 minutes, and realize that the depth of the surface compressive stress layer of the strengthened glass prepared according to the above method for preparing strengthened glass is not less than 75μm, and the surface compressive stress value is not low. At 650MPa.

(4) The preparation method of the above-mentioned strengthened glass has lower requirements for the accuracy of molten salt: in the traditional chemical strengthening process, after the molten salt is used for a period of time, the concentration of the molten salt will obviously deviate. Taking ^{the change of Na +} concentration as an example, ^{the change range of Na +} concentration is generally controlled within 6000 ppm, and more strictly controlled within 4000 ppm. Once ^{the deviation of Na +} concentration in molten salt exceeds this range, the enhanced performance cannot be guaranteed. . Therefore, the traditional chemical strengthening process requires frequent replacement of molten salt to meet the processing yield. The method for preparing the above-mentioned strengthened glass adopts the above-mentioned aluminosilicate glass and controls the conditions of ion exchange, so that the Na ⁺ concentration of the molten salt varies within 20,000 ppm, which greatly prolongs the service life of the molten salt, improves production efficiency and improves processing quality. Rate and reduce production costs.

A strengthened glass prepared according to the above-mentioned method for preparing strengthened glass according to an embodiment. The depth of the surface compressive stress layer of the strengthened glass is not less than 75 μm, and the surface compressive stress value is not less than 650 MPa. When the thickness of the strengthened glass is 0.5 mm, the intermediate tensile stress of the strengthened glass is not higher than 80 MPa; when the thickness of the strengthened glass is 0.7 mm, the intermediate tensile stress of the strengthened glass is not higher than 60 MPa. The strengthened glass has excellent resistance to falling and breaking on rough ground, resistance to mechanical impact, and good drop resistance.

The application of the above-mentioned strengthened glass in one embodiment in the preparation of a cover plate or a back plate. In addition, an embodiment of the above-mentioned strengthened glass is used in the preparation of an apparatus containing strengthened glass.

An apparatus according to an embodiment includes the above-mentioned strengthened glass.

In this embodiment, the device is an electronic device, such as a mobile phone, a tablet computer, and the like.

Specifically, the above-mentioned device includes a cover plate, and the cover plate includes the above-mentioned strengthened glass. Further, the cover plate is made by processing the above-mentioned strengthened glass.

In one of the embodiments, the above-mentioned device includes a back plate, and the back plate includes the above-mentioned strengthened glass. Further, the back plate is made by processing the above-mentioned strengthened glass.

In one of the embodiments, the above-mentioned device includes a cover plate and a back plate, the cover plate includes the above-mentioned strengthened glass, and the back plate includes the above-mentioned strengthened glass.

Of course, in some other embodiments, the device is a non-electronic device, and the device includes the above-mentioned strengthened glass.

Because the above-mentioned device includes the above-mentioned strengthened glass, it has good anti-drop performance.

Specific embodiment

The detailed description will be given below in conjunction with specific embodiments. Unless otherwise specified, the drugs and instruments used in the examples are all conventional choices in the art. The experimental methods that do not specify specific conditions in the examples are implemented in accordance with conventional conditions, such as the conditions described in the literature, books, or the method recommended by the manufacturer.

Example 1 to Example 30

(1) Weigh the raw materials and glass clarifiers of Examples 1 to 30 respectively, and then fully stir and mix the raw materials of the respective examples and the corresponding glass clarifiers to obtain the batches of the respective examples. Then put the batch materials of each example into a platinum crucible greater than 400mL and put it into a silicon-molybdenum furnace. Then the temperature of each example was raised to 1680°C for melting, and the materials were melted and clarified for 8 hours to make the raw materials of each example Homogenize to obtain the molten glass of each example.

(2) Cast the molten glass of each embodiment into corresponding molds, and then perform precision annealing at 600° C. to obtain rectangular aluminosilicate glass plates of each embodiment. Then use XRF, ICP and chemical titration methods (entrusted to the Shanghai Institute of Ceramics, Chinese Academy of Sciences) to test the chemical composition of the aluminosilicate glass plates of each embodiment; The acid salt glass was subjected to a high temperature viscosity test to determine the melting and refining temperature Tm (10 ² dPa.s) of the aluminosilicate glass of each example. The results are shown in Tables 1 to 5.

(3) Precision cutting was performed on the aluminosilicate glass plates of each example. Then, the precision-cut aluminosilicate glass samples of each embodiment were tested for thermal expansion performance using the PC402L horizontal dilatometer of Germany NETZSCH to determine the glass transition temperature Tg (10 ^13.4 dPa.s), Thermal expansion performance (35°C to 350°C, 350°C to 500°C), the results are shown in Table 1 to Table 5.

(4) Grinding and polishing the surface of the aluminosilicate glass plate of each embodiment after precision cutting, respectively, to obtain the aluminosilicate glass plate after grinding and polishing treatment of each embodiment, wherein the polishing used in the polishing treatment The powder is cerium oxide. The diagonal length of the aluminosilicate glass plate of each embodiment after the grinding and polishing treatment is 6 inches, and the thickness of the aluminosilicate glass plate of each embodiment after the grinding and polishing treatment is 0.7 mm. The Vickers microhardness test was performed on the aluminosilicate glass plates of each embodiment after the grinding and polishing treatments, and the results are shown in Tables 1 to 5.

(5) The aluminosilicate glass plates after the grinding and polishing treatments of the respective examples were chemically strengthened according to the strengthening conditions corresponding to Tables 1 to 5 to obtain the strengthened glass of each example. Among them, the strengthening conditions include _{the mass percentages of NaNO 3} and KNO ₃ , ion exchange temperature (T), and ion exchange time (τ). After the tempered glass of each embodiment is cooled, the tempered glass of each embodiment is cleaned with an ultrasonic cleaning machine for 1 hour to remove the remaining molten salt, and then dried.

(4) Performance test of the strengthened glass of each example: Vickers microhardness test was performed on the strengthened glass of each example, and the results are shown in Tables 1 to 5. The instruments are FSM-6000LE birefringent stress meter and scattered photo-photoelastic stress meter SLP-1000 to perform CS and DOL tests on the strengthened glass of each embodiment after ion exchange. Using a birefringent imaging system, polarized light of a specific wavelength passes through a glass with a stress gradient to produce a refractive optical path difference. The surface stress value CS, surface compressive stress layer depth DOL, and shallow stress layer depth of the strengthened glass of each embodiment are calculated DOL-tp (DOL-tp refers to the depth of the stress layer where the superficial stress value is higher than 300MPa) and the central tensile stress CT.

Table 1

Table 2

table 3

Table 4

table 5

It can be seen from Table 2 to Table 4 that the thermal expansion coefficient of the aluminosilicate glass of Example 1 to Example 26 at 35℃～350℃ is not higher than 95×10 ^-7 ℃ ^-1 , 350℃～550℃ The coefficient of thermal expansion is not higher than 100×10 ^-7 ℃ ^-1 ; the glass transition temperature of the aluminosilicate glass of embodiment 1 to embodiment 26 is not lower than 513 ℃, the aluminosilicate of embodiment 1 to embodiment 26 The surface micro Vickers hardness of the glass is not less than 626HV. After chemical strengthening, the surface compressive stress values of the strengthened glass of Examples 1 to 26 are 680 MPa to 850 MPa, the depth of the surface compressive stress layer is not less than 75 μm, and the depth of the superficial stress layer is 8 μm to 19.5 μm. The surface micro Vickers hardness of the strengthened glass of Example 1 to Example 26 is not less than 700HV.

The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the various technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, All should be considered as the scope of this specification.

The above-mentioned embodiments only express several embodiments of the present invention, and the descriptions are relatively specific and detailed, but they should not be understood as limiting the scope of the invention patent. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can be made, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims (20)

1. An aluminosilicate glass, in terms of mass percentage, comprising 55%-65% SiO ₂ , 13%-26% Al ₂ O ₃ , 2%-6% Li ₂ O, 6%-11 % Na ₂ O, 1% to 6% K ₂ O, 0.1% to 3% B ₂ O ₃ and 0.1% to 4% ZrO ₂ .
2. The aluminosilicate glass according to claim 1, wherein _{the mass percentage of the SiO 2} is 58% to 63%; and/or

   The mass percentage of the Al ₂ O ₃ is 16%-24%; and/or

   The mass percentage of the Li ₂ O is 3% to 5.5%; and/or

   The percentage by mass of the Na ₂ O is 7%-10%; and/or

   The mass percentage of the K ₂ O is 2.5%-4%.
3. The aluminosilicate glass according to claim 2, wherein _{the mass percentage of the Al 2} O ₃ is 19%-22%.
4. The aluminosilicate glass according to any one of claims 1 to 3, characterized in that, in terms of mass percentage, the aluminosilicate glass further comprises MgO with a content of not more than 4%; and/or

   In terms of percentage by mass, the aluminosilicate glass also includes ZnO with a content of not more than 3%; and/or

   In terms of mass percentage, the aluminosilicate glass also includes P ₂ O _{5 with a} content of not more than 3%.
5. The aluminosilicate glass according to claim 4, wherein the mass percentage of the MgO is 1% to 3%; and/or

   The mass percentage content of the ZnO does not exceed 1.5%; and/or

   The mass percentage content of the P ₂ O ₅ does not exceed 1%.
6. A method for preparing strengthened glass includes the following steps:

   The aluminosilicate glass according to any one of claims 1 to 5 is immersed in a molten salt for ion exchange to obtain a strengthened glass; wherein the molten salt includes NaNO ₃ and KNO ₃ , and in the ion exchange, said aluminosilicate glass Li ⁺ ratio of Na ⁺ in the molten salt, and the exchange rate of the aluminosilicate glass with the molten salt Na ⁺ K ⁺ exchange rate of 4.8 to 6.3.
7. The preparation method of strengthening glass according to claim 6, wherein, Na Li of the aluminosilicate glass with the molten salt ⁺ Na ⁺ exchange rate and the aluminosilicate glass with ^{+ The ratio of the K +} exchange rate of the molten salt is 5.5 to 6.3.
8. The method for preparing strengthened glass according to claim 6, wherein the molten salt comprises 5% to 25% NaNO ₃ and 75% to 95% KNO ₃ in terms of mass percentage; and/or

   The temperature of the ion exchange is 390°C to 460°C; and/or

   The time of the ion exchange is more than 180 min.
9. The method for preparing strengthened glass according to any one of claims 6 to 8, wherein the molten salt comprises 5% to 10% NaNO ₃ and 90% to 95% KNO in terms of mass percentage. ₃ ; and/or

   The temperature of the ion exchange is 410°C to 440°C; and/or

   The time of the ion exchange is 180 min to 300 min.
10. The method for preparing strengthened glass according to claim 9, wherein the time of the ion exchange is 210 min to 270 min.
11. The method for preparing strengthened glass according to claim 6, characterized in that in the step of immersing the aluminosilicate glass according to any one of claims 1 to 5 in molten salt for ion exchange to obtain strengthened glass After that, it also includes the step of removing the molten salt on the surface of the strengthened glass.
12. The method for preparing strengthened glass according to claim 6, characterized in that in the step of immersing the aluminosilicate glass according to any one of claims 1 to 5 in molten salt for ion exchange to obtain strengthened glass Before, it also includes the step of preparing the aluminosilicate glass.
13. The method for preparing strengthened glass according to claim 12, wherein the step of preparing the aluminosilicate glass comprises:

    Mixing the raw materials for preparing the silicate glass and the glass fining agent, and then performing melting treatment under the conditions of 1600°C to 1680°C to obtain molten glass; and

    The molten glass is shaped and then annealed at 550°C to 650°C to obtain the silicate glass.
14. The method for preparing strengthened glass according to claim 13, wherein the temperature of the melting treatment is 1650°C to 1680°C; and/or

    The annealing temperature is 600°C to 650°C.
15. The method for preparing strengthened glass according to claim 6, characterized in that in the step of immersing the aluminosilicate glass according to any one of claims 1 to 5 in molten salt for ion exchange to obtain strengthened glass Before, it also includes the step of polishing the aluminosilicate glass.
16. The method for preparing strengthened glass according to claim 15, characterized in that, after the step of polishing the aluminosilicate glass, it further comprises performing a hot bending treatment on the aluminosilicate glass A step of.
17. A strengthened glass prepared by the method for preparing strengthened glass according to any one of claims 6-16.
18. A cover plate comprising the strengthened glass of claim 17.
19. A backplane comprising the strengthened glass of claim 17.
20. A device comprising the strengthened glass of claim 17.