CN114920454A - Method for preparing lithium aluminum silicon glass and treating micro-defects on glass surface after strengthening of lithium aluminum silicon glass - Google Patents

Abstract

The invention relates to the technical field of processing and manufacturing of lithium aluminum silicon glass, in particular to a method for treating micro defects on the surface of glass after preparation and strengthening of the lithium aluminum silicon glass. The lithium aluminum silicon glass prepared by the raw materials in parts by mass provided by the invention has good various performances. Meanwhile, the original strengthened lithium aluminum silicon glass with surface defects is repaired by the microdefect treatment method to prepare the secondary repaired lithium aluminum silicon glass, the secondary repaired lithium aluminum silicon glass has good performances, the processing steps are simple, and the processing requirements of electronic products can be met, so that the production cost and the energy consumption are effectively reduced, the resource utilization rate and the enterprise economic benefit are improved, and the damage of wastes to the environment is reduced.

Description

Method for preparing lithium aluminum silicon glass and treating micro-defects on glass surface after strengthening of lithium aluminum silicon glass

Technical Field

The invention relates to the technical field of processing and manufacturing of lithium aluminum silicon glass, in particular to a method for treating micro defects on the surface of glass after preparation and strengthening of the lithium aluminum silicon glass.

Background

With the development of electronic technology and IT technology and the lightness, thinness and miniaturization of electronic equipment, the ultrathin glass has important application value in the aspects of mobile phones, flat plates, intelligent wearable products and the like, and the demand is continuously increased. The ultra-thinning of glass and the surface microcrack inevitably bring about the reduction of the mechanical property of the product, thereby restricting the development of the industry, and industrial practitioners always work to overcome the difficulty. At present, the chemical strengthening technology is mainly adopted for improving the mechanical properties of the ultrathin glass, and the chemical strengthening is to perform exchange through alkali metal ions with different radiuses of different groups and prefabricate compressive stress on the surface of the glass to improve the mechanical properties of the glass, such as falling resistance, ball falling resistance, scratch resistance, bending strength and the like.

It is noteworthy that when the glass undergoes post chemical strengthening, a change in geometry will occur, and currently, low thickness glass made by thin glass processes has a large expansion ratio after chemical tempering. The expansion ratio is determined by dividing the difference in sample length before and after chemical tempering by the original length before chemical tempering, and therefore, the expansion ratio is calculated according to the following formula: the expansion rate (after the length tempering-before the length tempering)/before the length tempering is higher, when the glass is thinner, the expansion caused by the chemical tempering process becomes larger, and the larger expansion rate of the glass limits the application of the lithium aluminosilicate glass in high-precision equipment.

Meanwhile, the current lithium aluminum silicon glass processing procedure is relatively complex and has strict requirements on the processing technology, and certain damage to part of the glass surface can be inevitably caused in the whole processing process, so that the mechanical property of the product is reduced. At present, for the products with microdefects on the surfaces, the common method is to directly scrap the products with microdefects on the surfaces, but directly discarding unqualified products causes environmental pollution and increases the enterprise cost, and is not beneficial to ecological protection and increases the economic benefits of enterprises. The chinese patent publication No. CN102875035A discloses a method for repairing defective glass products, which comprises the steps of: A. contacting the defective product with a melting de-hardening agent, and performing de-hardening to obtain a glass reduction product; B. polishing the glass reduction product obtained in the step A to obtainA glass preform; C. and D, contacting the glass prefabricated product in the step B with a melting reinforcer for reinforcement to obtain a good glass product. The method for repairing the defective products reduces the defective products into the unreinforced glass by performing annealing and strengthening on the defective products, thereby effectively ensuring the repair yield. The Chinese patent with the publication number of CN 109265016A discloses a method for reworking GG5 material 3D glass, and the method for reworking GG5 material 3D glass firstly utilizes chemical reverse strengthening to reversely strengthen Na with smaller diameter in solution⁺ And Li⁺ Ion bonding of larger diameter K in glass surface stress layer⁺ And (3) displacing ions to achieve the effect of eliminating the stress layer on the surface of the glass, and then carrying out chemical strengthening on the glass subjected to reverse strengthening and the material A again, so that the problem of recycling the glass with defects on the surface is solved. However, in actual work, the applicant finds that a chemical de-strengthening method is used for repairing a glass product, after the glass product is subjected to a chemical de-strengthening process, part or all of the performance of the glass product is inevitably reduced compared with that of the original glass product, and even if the glass is re-strengthened in a subsequent repairing process, the performance of the glass product is inevitably reduced compared with that of the glass which is not subjected to the repairing process, so that the requirements in actual use are difficult to meet, and therefore, a more scientific and better treatment method for the surface defects of the glass is required in the actual processing process.

Disclosure of Invention

In order to solve the above technical problems, the present invention aims to provide a method for treating micro defects on a glass surface after lithium aluminum silicate glass preparation and strengthening thereof, so as to effectively solve the defects in the prior art.

In order to achieve the technical effect, the invention adopts the following technical scheme:

in a first aspect, the lithium aluminosilicate glass provided by the invention is prepared from the following raw materials in parts by mass:

SiO₂ : 63.2 to 68.3 parts of Al₂ O₃ : 10.05-15.24 parts of Na₂ O: 1.5 to 12.2 parts of K₂ O: 0.1-0.9 part of Li₂ O: 9-11.5 parts of MgO: 2.1 &4 parts and ZrO₂ : 0.2 to 1.5 portions.

Further, the thickness of the lithium aluminosilicate glass is 0.55mm-1 mm.

In a second aspect, the invention provides a preparation method of lithium aluminosilicate glass, wherein the lithium aluminosilicate glass is prepared by adopting the raw material components, and the preparation method specifically comprises the following steps:

a1: preparing lithium-aluminum-silicon glass by adopting a melting-forming method;

a2: and (4) chemically strengthening the lithium aluminosilicate glass prepared from the A1 to obtain the original strengthened lithium aluminosilicate glass.

A3: and detecting the surface micro-defects of the prepared original strengthened lithium aluminum silicate glass to distinguish defective products from qualified products, and repairing the surface micro-defects of the defective products.

Further, the original strengthened lithium aluminum silicate glass is obtained through a secondary strengthening treatment process.

Further, the secondary strengthening treatment process conditions adopted when the original strengthened lithium aluminum silicate glass is strengthened are as follows:

primary strengthening: using KNO₃ And NaNO₃ The mixed solution of (A) is used for strengthening the tempered glass, and the KNO₃ And NaNO₃ KNO in the mixed solution of (1)₃ KNO with the content of 40 to 50 weight percent₃ The treatment temperature is 420-440 ℃, and the treatment time is 1.5-2.5 h.

And (3) strengthening again: 100 wt% KNO₃ The solution is processed at 415-420 ℃ for 1.5-2.0 h.

Further, the a1 specifically includes:

a1 a: melting: uniformly mixing the raw materials in parts by mass at the temperature of 1480-1580 ℃, and melting the mixture to prepare bubble-free molten glass liquid with uniform chemical composition so as to ensure that all ions in the raw material composition are fully diffused;

a1 b: molding: the bubble-free molten glass liquid with uniform chemical composition obtained from A1a is prepared into the lithium aluminosilicate glass by a float forming method, and the thickness of the lithium aluminosilicate glass is between 0.5 and 1mm, and preferably between 0.55 and 0.7 mm.

In a third aspect, the invention further provides a method for processing micro defects on the surface of glass after the lithium aluminosilicate glass is strengthened, which specifically comprises the following steps:

b1: grinding, polishing and thinning the two sides of the defective product to process the defective product into tempered glass so as to achieve the purpose of tempering;

b2: chemically strengthening the de-strengthened glass obtained from the B1 again to prepare secondary repair lithium aluminum silicate glass;

b3: cleaning: sequentially carrying out citric acid washing, alkali liquor washing and pure water washing on the secondarily repaired lithium-aluminum-silicon glass obtained after the repairing is finished, and then drying for later use;

b4: and (3) detection: checking the appearance condition of the repaired secondary repair lithium aluminum silicon glass, specifically, detecting whether the repaired lithium aluminum silicon glass has surface defects, and testing various performances of the secondary repair lithium aluminum silicon glass obtained after the repair, specifically: the secondary repaired lithium aluminosilicate glass obtained after the repair has perfect surface and no micro defects such as scratch, and the various properties of the repaired lithium aluminosilicate glass comprise: the surface Compressive Stress (CS) is 830-963 MPa, the thickness (DOL) of the stress layer is 101-117 μm, the compressive stress (CS _30) at a position 30 μm away from the surface is 101-136 MPa, the thickness (H) of the potassium stress layer is 5.5-7.6 μm, the bending strength (4PB) is 800-926 MPa, the ball drop height (H) is 55-68 CM, and the expansion rate is less than 0.05%.

Furthermore, the thickness of the stress layer of the defective product in B1 on two sides before repair is larger than or equal to 100um, and the thickness of the polishing thinning in B1 is controlled to be 5-30 mu m so as to keep a certain stress layer.

Further, the B1 comprises coarse grinding and fine grinding which are sequentially carried out, wherein the coarse grinding comprises the following steps:

b1a 1: side polishing: concentration of polishing powder: 1.1-1.3 g/mL, polishing time: 5-8 min, rotation speed: less than or equal to 50 r/min;

b1a 2: 2.5D scanning: concentration of polishing powder: 1.1-1.2 g/mL, polishing time: 5-8 min, rotation speed: less than or equal to 50 r/min;

b1a 3: upper sweeping, lower throwing and flat throwing: concentration of polishing powder: 1.0-1.1 g/mL, polishing time: 10-20 min, rotation speed: less than or equal to 40 r/min;

the fine grinding comprises the following steps: sweeping up and throwing down, LP: concentration of polishing powder: 1.0-1.1 g/mL, polishing time less than or equal to 5min, rotating speed: is less than or equal to 40 r/min. Further, the chemical strengthening process in B2 specifically includes the following steps:

b2 a: preheating: preserving the temperature of the polished annealed glass at 350-390 ℃ for 10-30 min;

B2B: strengthening: transferring the preheated annealed glass to a tempering furnace filled with strengthening treatment liquid for strengthening treatment, wherein the strengthening treatment can be a primary strengthening treatment process or a secondary strengthening treatment process;

b2 c: and (3) annealing: dropping salt into the tempered glass after the tempering treatment for 10-15 min, transferring the tempered glass into an annealing furnace at 350-380 ℃, preserving the heat for 30-60 min, and then cooling to normal temperature at a cooling rate of 3-6 ℃/min to prepare secondary repair lithium aluminum silicon glass; or is as follows: dropping salt into the tempered glass after the strengthening treatment for 10-15 min, transferring the tempered glass into an annealing furnace at 350-380 ℃, preserving heat for 20-40 min, then cooling to 230-250 ℃ at the rate of 8-15 min/DEG C, preserving heat for 10-30 min, cooling to 100-120 ℃ at the rate of 8-15 min/DEG C, and then cooling to room temperature along with the furnace.

Further, the strengthening treatment of B2B is a primary strengthening treatment process, which specifically includes: using KNO₃ And NaNO₃ The mixed solution of (a) is used for strengthening the tempered glass, the KNO₃ And NaNO₃ KNO in the mixed solution of (1)₃ KNO with the content of 94 to 95 weight percent₃ 。

Further, when the secondary strengthening treatment process is adopted, the secondary strengthening process specifically comprises the following steps:

s1: using KNO₃ And NaNO₃ The mixed solution of (A) preliminarily strengthens the annealed and tempered glass, KNO₃ And NaNO₃ KNO in the mixed solution of (1)₃ The content of KNO is 3 to 95 weight percent₃ ；

S2: using 100 wt% KNO₃ And re-strengthening the de-strengthened glass after the primary strengthening at the temperature of 400-440 ℃.

Further, the cleaning step of B2d specifically includes: the citric acid concentration of the citric acid washing is 3-5%, the pH value is 2-3, and the washing temperature is 70 +/-2 ℃; washing with an alkali solution, namely NaOH with the concentration of 2-3%, the pH value of 12-13 and the washing temperature of 50 +/-2 ℃; the cleaning temperature of pure water is 50 +/-2 ℃, and the cleaning time is 15-30 min; the drying temperature is 55-65 ℃.

Compared with the prior art, the invention has the following beneficial effects:

in a first aspect, the raw material composition and the preparation method of the lithium aluminosilicate glass provided by the invention are simple and easy to implement, and the original strengthened lithium aluminosilicate glass prepared by the invention has excellent mechanical properties, especially a low expansion rate.

In a second aspect, the method for processing the micro defects on the surface of the tempered glass provided by the invention comprises the steps of polishing and thinning the original tempered lithium aluminum silicon glass with surface defects to perform de-tempering, then re-tempering the de-tempered glass to obtain the secondary tempered lithium aluminum silicon glass with excellent performance, wherein in the repair process, the performance of the secondary tempered lithium aluminum silicon glass is obviously improved by controlling the thickness reduction and thinning mode in the polishing and thinning treatment and enabling the de-tempered glass to still keep a certain stress layer, and then the de-tempered glass is re-tempered, so that the method has the characteristic of exceeding the performance of the original tempered lithium aluminum silicon glass. In addition, in the repair process, the repair steps are simple, the repair is easy to implement in the production and machining process, the repair process efficiency is high, the method is suitable for repairing the lithium aluminum silicon glass sample in the market, the application range is wide, the production cost and the energy consumption can be effectively reduced, the resource utilization rate and the enterprise economic benefit can be improved, the damage of waste to the environment can be reduced, and the enterprise competitive advantage can be improved.

Detailed Description

The following examples are only for illustrating the technical solutions of the present invention more clearly, and therefore are only examples, and the protection scope of the present invention is not limited thereby. Meanwhile, in the following examples and comparative examples, all the compounds or starting materials used are commercially available products unless otherwise specified.

The invention provides a group of examples 16 which are recorded as examples 1-16 respectively, and a group of comparative examples 3 which are recorded as comparative examples 1-3 respectively, wherein the comparative examples 1-3 are all originally prepared strengthened lithium aluminosilicate glasses without surface defects, and the examples 1-16 are all secondary repair lithium aluminosilicate glasses obtained after reworking the originally strengthened lithium aluminosilicate glasses with surface defects, wherein the raw material compositions (mass parts) of the examples 1-16 and the comparative examples 1-3 are shown in the table 1 (mass parts); specific tempering parameters of the example 1 to the example 16 and the comparative example 1 to the comparative example 3 are shown in table 2; specific parameters of the polishing thinning process of the embodiment 1 to the embodiment 16 are shown in table 3; the performance tests of the secondary repaired lithium aluminosilicate glasses prepared in examples 1-16 and the original strengthened lithium aluminosilicate glasses obtained in comparative examples 1-3 are shown in table 4:

TABLE 1 raw material compositions of example 1 to example 16 and comparative example 1 to comparative example 3

Table 2 tempering parameters of examples 1 to 16 and comparative examples 1 to 3

Table 3 polish thinning process parameters for examples 1-16

It should be noted that the polishing powder used in the polishing and thinning process in examples 1 to 16 was prepared according to the composition of example 1 of the chinese patent application publication No. CN 110564304B.

Table 4 results of performance test of examples 1 to 16 and comparative examples 1 to 3

It should be noted that, in the above performance test, some of the test methods used in the examples and comparative examples are as follows:

(1)4PB (MPa) test method

The bending resistance of the glass is characterized by a four-point bending value (namely 4PB), and the test method is as follows:

the four-point bending test is carried out on the glass sample by using a universal testing machine, and the test conditions are as follows: up/down span 20/40mm, pressing speed 10mm/min, rod diameter 6mm.

(2) Falling ball (cm) test method

The impact resistance of the glass is characterized by the falling ball height, and the test method comprises the following steps:

using a falling ball impact testing machine to carry out a central point falling ball test on a glass sample, wherein the test conditions are as follows: 130g of steel ball, 15cm of base height, 5cm of base height, and a central point, wherein each height is 1 time until the steel ball is broken. At least five samples were tested and averaged.

(3) Expansion ratio (%) test

And (3) detecting the expansion rate of the external dimension of the original strengthened lithium-aluminum-silicon glass and the external dimension of the secondary strengthened lithium-aluminum-silicon glass before and after chemical strengthening by using a quadratic element measuring instrument.

The performance test result table shows that the original strengthened lithium aluminum silicon glass prepared by the method and the secondary strengthened lithium aluminum silicon glass obtained by surface defect repair have good performances and lower expansion rate.

In addition, the pristine strengthened lithium aluminosilicate glass was prepared by the method of comparative example 1, and a defective product was selected from the pristine strengthened lithium aluminosilicate glass and repaired. Specifically, after reworking the original strengthened lithium aluminum silicate glass with surface defects by the method of example 4, a secondary strengthened lithium aluminum silicate glass is obtained, 6 groups of samples are processed in the experiment, the thickness of the original strengthened lithium aluminum silicate glass is 0.55mm, and the processing groups are respectively recorded as No.1-No. 6; the method of example 8 is adopted to repair the original strengthened lithium aluminum silicon glass with surface defects to obtain secondary strengthened lithium aluminum silicon glass, and the thickness of the original strengthened lithium aluminum silicon glass is d 0.6mm, 8 groups of samples are processed in the experiment, and the processing groups are respectively recorded as NO.7-NO. 14; after reworking the pristine strengthened lithium aluminosilicate glass having surface defects by the treatment method of example 9 to obtain a secondary strengthened lithium aluminosilicate glass, wherein the thickness d of the pristine strengthened lithium aluminosilicate glass is 0.7mm, the procedure was carried out to treat 9 groups of samples in total, and the treated groups are respectively recorded as No.15-No. 23.

Whether the samples before and after the samples NO.1-NO.23 are processed are warped or not is detected, the detection results are shown in Table 5, and the experimental results show that the original strengthened lithium-aluminum-silicon glass with surface defects is repaired by the method, and the warping degrees of the samples before and after the repair meet the requirements.

TABLE 5 warpage detection data of samples No.1-No.23 before and after treatment

Although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the true spirit and scope of the present invention, which is defined by the claims appended hereto. The techniques, shapes, and configurations not described in detail in the present invention are all known techniques.

Claims (10)

1. The lithium aluminosilicate glass is characterized by being prepared from the following raw materials in parts by mass: SiO 2₂ : 63.2 to 68.3 parts of Al₂ O₃ : 10.05-15.24 parts of Na₂ O: 1.5 to 12.2 parts of K₂ O: 0.1-0.9 part of Li₂ O: 9-11.5 parts of MgO: 2.1 to 4 parts and ZrO₂ : 0.2-1.5 parts.

2. The method of making a lithium aluminosilicate glass according to claim 1, comprising the steps of:

a1: preparing lithium-aluminum-silicon glass by adopting a melting-forming method;

a2: and (4) chemically strengthening the lithium aluminosilicate glass prepared from the A1 to obtain the original strengthened lithium aluminosilicate glass.

3. The method for preparing a lithium aluminosilicate glass according to claim 2, wherein the a1 specifically comprises:

a1 a: melting: melting the raw materials at 1480-1580 ℃ to prepare bubble-free molten glass liquid with uniform chemical composition;

a1 b: molding: and preparing the bubble-free molten glass into the lithium-aluminum-silicon glass by adopting a float forming method.

4. The method of making a lithium aluminosilicate glass according to claim 1, further comprising step A3, wherein A3 is: and detecting the surface micro-defects of the prepared original strengthened lithium-aluminum-silicon glass to distinguish defective products and qualified products, and repairing the surface micro-defects of the defective products.

5. A method for processing micro defects on the surface of glass after lithium aluminum silicon glass strengthening is characterized by comprising the following steps:

b1: grinding, polishing and thinning two sides of the defective product to process the defective product into tempered glass;

b2: the de-strengthened glass obtained from B1 was again chemically strengthened to prepare a secondary repair lithium aluminosilicate glass.

6. The method for treating the micro-defects on the surface of the glass after the lithium aluminosilicate glass is strengthened according to claim 5, wherein the thickness of the ground, polished and thinned is controlled to be 5-30 μm.

7. The method for treating the micro-defects on the surface of the lithium aluminosilicate glass after being strengthened, according to claim 5, wherein the step B1 comprises the steps of rough grinding and finish grinding which are sequentially carried out, wherein the rough grinding comprises the following steps:

b1a 1: side polishing: concentration of polishing powder: 1.1-1.3 g/mL, polishing time: 5-8 min, rotation speed: less than or equal to 50 r/min;

b1a 2: 2.5D scanning: concentration of polishing powder: 1.1-1.2 g/mL, polishing time: 5-8 min, rotating speed: less than or equal to 50 r/min;

b1a 3: upper sweeping, lower throwing and flat throwing: concentration of polishing powder: 1.0-1.1 g/mL, polishing time: 10-20 min, rotating speed: less than or equal to 40 r/min;

the fine grinding comprises the following steps: upper sweeping and lower throwing and LP: concentration of polishing powder: 1.0-1.1 g/mL, polishing time less than or equal to 5min, rotating speed: is less than or equal to 40 r/min.

8. The method for treating the micro-defects on the surface of the glass after the lithium aluminosilicate glass is strengthened according to claim 5, wherein the chemical strengthening process in B2 comprises the following steps:

b2 a: preheating: preserving the temperature of the polished annealed glass at 350-390 ℃ for 10-30 min;

B2B: strengthening: transferring the preheated annealed glass to a tempering furnace filled with strengthening treatment liquid for strengthening treatment, wherein the strengthening treatment can be a primary strengthening treatment process or a secondary strengthening treatment process;

b2 c: and (3) annealing: and dripping salt into the tempered glass after the tempering treatment for 10-15 min, transferring the tempered glass into an annealing furnace at 350-380 ℃, preserving the heat for 30-60 min, and then cooling to the normal temperature at the cooling rate of 3-6 ℃/min to prepare the secondary repair lithium aluminum silicate glass.

9. The method for treating the micro-defects on the glass surface after the lithium aluminosilicate glass is strengthened according to claim 8, wherein the strengthening treatment of B2B is a primary strengthening treatment process, which comprises the following specific steps: using KNO₃ And NaNO₃ The mixed solution of (A) is used for strengthening the tempered glass, and the KNO₃ And NaNO₃ KNO in the mixed solution of (1)₃ KNO with the content of 94 to 95 weight percent₃ 。

10. The method for treating the micro-defects on the glass surface after the lithium aluminosilicate glass is strengthened according to claim 8, wherein the strengthening treatment of B2B is a secondary strengthening treatment process, and the method specifically comprises the following steps:

s1: using KNO₃ And NaNO₃ The mixed solution preliminarily strengthens the tempered glass, and the KNO₃ And NaNO₃ KNO in the mixed solution of (1)₃ KNO with the content of 3 to 95 weight percent₃ ；

S2: using 100 wt% KNO₃ And re-strengthening the de-strengthened glass after the primary strengthening at the temperature of 400-440 ℃.