CN114591005A - Repairing method of lithium aluminosilicate glass - Google Patents

Abstract

The invention discloses a method for repairing lithium aluminosilicate glass, and belongs to the field of glass preparation. The repairing method comprises the following steps: polishing the lithium aluminosilicate glass with the defects on the surface after chemical strengthening to eliminate the surface defects; and carrying out chemical strengthening twice on the polished lithium aluminosilicate glass, wherein the chemical strengthening twice comprises the following steps: placing the lithium aluminosilicate glass in a solution containing Na⁺And K⁺Strengthening in the first molten salt for 10-60 min at the strengthening temperature of 380-420 ℃; then placing the strengthened lithium aluminosilicate glass in a container containing K⁺Strengthening in the second salt bath for 20-90 min at a strengthening temperature of 380-430 ℃. The method can repair the lithium aluminosilicate glass with the surface scratch defect, has simple process and short time consumption, and can restore all the performances of the repaired lithium aluminosilicate glass to the initial state.

Description

Repairing method of lithium aluminosilicate glass

Technical Field

The invention belongs to the technical field of glass preparation, and particularly relates to a repairing method of lithium aluminosilicate glass.

Background

The mobile phone cover plate glass is mainly formed by machining and specifically comprises five procedures of cutting, CNC (computer numerical control), polishing, edge sweeping and chemical strengthening. Poor scratching is easily caused in the machining process, and poor scratching is also caused by inserting and transferring of glass in the machining process.

The current repair process of the defective lithium aluminosilicate glass GG5 comprises the following steps: (1) the glass to be reworked is placed into molten salt to be soaked for 8 to 20 hours at the temperature of 410 ℃ and 430 ℃ to eliminate the surface stress of the glass, so that the glass is restored to a non-stress state before strengthening; (2) carrying out fine grinding and polishing on the chemically reverse-strengthened glass to repair the defect defects on the surface of the glass; (3) and chemically strengthening the repaired glass. The repair method needs to restore the glass to a completely stress-free state before strengthening, takes long time, and needs to finish grinding and polishing the glass after stress is eliminated, so that secondary strengthening is needed again. The repair process is complex and long in time consumption, and the method is only suitable for GG5 glass at present, but other lithium aluminum silicate glass is not necessarily suitable.

Disclosure of Invention

The invention aims to provide a method for repairing lithium aluminosilicate glass, which can repair the lithium aluminosilicate glass with scratch defects on the surface, has simple process and short time consumption, and can restore all the performances of the repaired lithium aluminosilicate glass to the initial state.

The invention is realized by the following technical scheme:

a method of repairing lithium aluminosilicate glass, comprising:

polishing the lithium aluminosilicate glass with the defects on the surface after chemical strengthening to eliminate the surface defects;

and carrying out chemical strengthening twice on the polished lithium aluminosilicate glass, wherein the chemical strengthening twice comprises the following steps:

placing the lithium aluminosilicate glass in a solution containing Na⁺Or Na⁺And K⁺Strengthening in the first molten salt for 10-60 min at the strengthening temperature of 380-420 ℃; then placing the strengthened lithium aluminosilicate glass inContaining K⁺Strengthening in the second salt bath for 20-90 min at a strengthening temperature of 380-430 ℃.

Further, in a preferred embodiment of the present invention, the mass fraction of the sodium salt in the first molten salt is 50 to 100% by mass of the first molten salt.

In a preferred embodiment of the present invention, the mass fraction of the potassium salt in the first molten salt is 0 to 50% based on the mass of the first molten salt.

Further, in a preferred embodiment of the present invention, the strengthening time of the lithium aluminosilicate glass in the first molten salt is 20-30 min, the strengthening temperature is 390-410 ℃, and the mass ratio of the sodium salt to the potassium salt in the first molten salt is 50-60% to 50-40%.

Further, in a preferred embodiment of the present invention, the second molten salt contains 100% by mass of a potassium salt.

Further, in a preferred embodiment of the present invention, the strengthening time of the lithium aluminosilicate glass in the second molten salt is 20 to 70min, and the strengthening temperature is 390 to 410 ℃.

Further, in a preferred embodiment of the present invention, in the two chemical strengthening steps, Na is added⁺Derived from NaNO₃、Na₂CO₃、NaHCO₃、Na₃PO₄、Na₂SO₄And NaOH.

Further, in a preferred embodiment of the present invention, in the two chemical strengthening steps, K is⁺Derived from KNO₃、K₂CO₃、KHCO₃、K₃PO₄、K₂SO₄And KOH.

Further, in a preferred embodiment of the present invention, the polishing step includes polishing the lithium aluminosilicate glass on both sides, wherein each of the two sides is polished to 1 to 8 μm.

Further, in a preferred embodiment of the present invention, the polishing process is mechanical polishing.

Further, in a preferred embodiment of the present invention, after the polishing treatment and before the chemical strengthening treatment, the method further includes a step of performing a preheating treatment on the lithium aluminosilicate glass: heating the lithium aluminosilicate glass to 380-420 ℃ within 30-60 min, and keeping the temperature for 25-35 min.

Compared with the prior art, the invention at least has the following technical effects:

according to the repairing method of the lithium aluminosilicate glass, provided by the invention, the scratch defect on the surface of the lithium aluminosilicate glass is removed by adopting a grinding and polishing mode, and then the lithium aluminosilicate glass is subjected to chemical strengthening twice by adopting a specific strengthening condition, so that various performances of the obtained lithium aluminosilicate glass (namely the re-polished strengthened glass) can be recovered to the state before reverse polishing. The concrete is embodied in the following four aspects:

1. the surface stress value CS of the back-polished strengthened glass reaches the state before back polishing or is higher;

2. the total stress layer depth DOL of the back-polished tempered glass reaches the state before back polishing;

3. the stress distribution of the back-polished strengthened glass from the surface of the glass to the interior of the glass reaches the state before back polishing, such as the stress at the position of 40 mu m;

4. and the depth DOL _ K of the potassium stress layer of the back-polished tempered glass reaches the state before back-polishing.

The repairing method of the lithium aluminosilicate glass has the advantages of simple process and short time consumption, and the size of the lithium aluminosilicate glass is easily in a standard range and the performance is recovered as before by controlling the steps of polishing and chemical strengthening.

Drawings

FIG. 1 shows scratches on the surface of glass before back-polishing in example 1 of the present invention.

FIG. 2 shows the surface state of the glass after the strengthening by the back polishing in example 1 of the present invention.

Detailed Description

Embodiments of the present invention will be described in detail with reference to the following examples, but those skilled in the art will understand that the following examples are merely illustrative of the present invention and should not be construed as limiting the scope of the present invention, and that the specific conditions not specified in the examples are carried out according to conventional conditions or conditions suggested by the manufacturer, and that the reagents or equipment used are not specified by the manufacturer, and are all conventional products available through commercial purchase.

The technical scheme of the invention is as follows:

a method of repairing lithium aluminosilicate glass, comprising:

step S1: polishing the lithium aluminosilicate glass with the defects on the surface after chemical strengthening to eliminate the surface defects;

wherein, the mode of mechanical polishing is adopted in the polishing processing, and this application adopts the mode of grinding to carry out the polishing processing.

Further, in the polishing treatment process, the thickness of each polished surface of the lithium aluminosilicate glass is 1-8 μm. For some glasses with slight scratch defects, the polishing thickness needs to be at least 1 μm, and when the polishing thickness is less than μm, the defects on the surface of the glass cannot be completely removed; for some glasses with large scratch defects, the polishing thickness needs to be controlled below 8 μm, and when the polishing thickness exceeds 8 μm, the glass thickness is easily reduced too much, and the strength of the glass is affected. The thickness of each polished surface is preferably 2 to 7 μm, and may be, for example, 3 μm, 4 μm, 5 μm, or 6 μm.

In the repairing method provided by the application, when the lithium aluminosilicate glass is polished, only one side with the scratch defect can be polished by 1-8 μm, and the two sides with the scratch defect can also be polished. In the process of polishing the two surfaces, the polishing thickness of each surface can be the same or different.

Step S2: and carrying out chemical strengthening twice on the polished lithium aluminosilicate glass, wherein the chemical strengthening twice comprises the following steps:

placing the lithium aluminosilicate glass in a solution containing Na⁺And K⁺Strengthening in the first molten salt for 10-60 min at a strengthening temperature of 380-420 ℃; then placing the strengthened lithium aluminosilicate glass in a container containing K⁺Strengthening in the second salt bath for 20-90 min at a strengthening temperature of 380-430 ℃.

By first ion strengthening, Li in the glass⁺With Na in the first salt bath⁺Ion exchange is carried out to generate a second stress area on the strengthened glass,so as to enhance the strengthening depth and improve the shock resistance of the strengthened glass. Adding K simultaneously to the first salt bath⁺The glass has stable exchange performance, and the obtained glass does not need to be cleaned and is convenient for being directly reinforced for the second time.

Na in the glass by the second ion strengthening⁺With K in the second salt bath⁺Ion exchange is carried out to generate a first stress area on the strengthened glass so as to carry out surface enhancement.

Specifically, in the two chemical strengthening steps:

(1) in the first chemical strengthening process, the first molten salt simultaneously contains Na⁺And K⁺The mass ratio of the sodium salt to the potassium salt is 50-100% to 50-0% (preferably, the mass ratio of the sodium salt to the potassium salt is 50-60% to 50-40%). The mass of the sodium salt accounts for 50-100% of the mass of the first molten salt, and Na accounts for⁺Derived from NaNO₃、Na₂CO₃、NaHCO₃、Na₃PO₄、Na₂SO₄At least one of NaOH, K⁺Derived from KNO₃、K₂CO₃、KHCO₃、K₃PO₄、K₂SO₄And KOH.

The time for the first chemical strengthening is 10-60 min, preferably 15-55 min, more preferably 20-30 min, for example, 22min, 24min, 26min, 28min, etc.

The temperature of the first chemical strengthening is 380 to 420 ℃, preferably 390 to 410 ℃, for example 395 ℃, 400 ℃, 405 ℃ and the like.

(2) In the second chemical strengthening process, the second molten salt only contains K⁺I.e. the mass fraction of potassium salt is 100%, K⁺Derived from KNO₃、K₂CO₃、KHCO₃、K₃PO₄、K₂SO₄And KOH.

The time for the second chemical strengthening is 20 to 90min, preferably 20 to 70min, more preferably 25 to 65min, for example, 30min, 40min, 50min, 60min, etc.

The temperature of the second chemical strengthening is 380 to 430 ℃, preferably 390 to 410 ℃, for example 395 ℃, 400 ℃ and 405 ℃.

Further, after polishing and before chemical strengthening, the method also comprises the step of preheating the lithium aluminosilicate glass: heating the lithium aluminosilicate glass to 380-420 ℃ within 30-60 min, and keeping the temperature for 25-35 min; preferably, the preheating step comprises: heating the lithium aluminosilicate glass to 390-410 ℃ within 35-45 min, and keeping the temperature for 28-32 min.

The first, second, and the like in the names of substances described in (1) the embodiments of the present invention do not indicate the order or importance of the substances, and are merely named for distinguishing the substances.

(2) Each strengthening is followed by post-treatments such as desalting and annealing, and each strengthening is preceded by pre-treatments such as preheating of the lithium silicate glass, which are conventional operations known in the art and are not the point of the invention in the embodiments of the present invention, and therefore, the inventors do not go into any further detail.

The strengthening process of the lithium silicate glass provided by the invention is specifically described below with reference to specific examples.

Stress performance of the glass before back polishing: CS is 850MPa, CS40 is 110MPa, DOL is 120 μm, and DOLK is 6.0 μm.

After the glass is back-polished, the glass is strengthened according to strengthening conditions, and each of the glass sheets in each example and each comparative example is 20.

The following describes in detail specific embodiments of the present invention. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

Example 1

The embodiment provides a method for repairing lithium aluminosilicate glass, which comprises the following steps:

(1) polishing both surfaces of the defective lithium aluminosilicate glass product (scratch depth h is 1 μm, scratch width d is 43.58 μm) shown in fig. 1 by 1 μm, and removing the scratch defect on the glass surface;

(2) and (3) inserting the polished lithium aluminosilicate glass into a toughening frame, then putting the toughened glass into a preheating furnace for preheating, raising the temperature from room temperature (about 25 ℃), raising the temperature to 380 ℃ within 30min, and preserving the temperature for 30min to finish preheating.

(3) Then putting the sample into first molten salt for strengthening, wherein the strengthening conditions are as follows: the temperature is 390 ℃, the time is 20min, and NaNO is in the first molten salt₃And KNO₃The mass fraction of (A) is 50%.

(4) And then putting the reinforced sample into second molten salt for reinforcement, wherein the reinforcement conditions are as follows: temperature of 390 deg.C, time of 20min, KNO in the first molten salt₃Is 100 percent.

(5) And after the strengthening is finished, transferring the glass into the air for natural cooling to obtain the lithium aluminosilicate glass with a flat surface as shown in figure 2.

Example 2

The embodiment provides a method for repairing lithium aluminosilicate glass, which comprises the following steps:

(1) polishing two surfaces of the defective lithium aluminosilicate glass product by 3 microns respectively to remove scratch defects on the surface of the glass;

(2) and (3) inserting the polished lithium aluminosilicate glass into a toughening frame, then putting the toughened glass into a preheating furnace for preheating, starting to heat up from room temperature (about 25 ℃), heating to 380 ℃ within 60min, and preserving heat for 30min to finish preheating.

(3) Then putting the sample into first molten salt for strengthening, wherein the strengthening conditions are as follows: the temperature is 400 ℃, the time is 30min, and NaNO is in the first molten salt₃And KNO₃The mass fraction of (A) is 50%.

(4) And then putting the reinforced sample into second molten salt for reinforcement, wherein the reinforcement conditions are as follows: the temperature is 400 deg.C, the time is 40min, KNO in the first molten salt₃Is 100 percent.

(5) And transferring the glass to the air for natural cooling after the strengthening is finished.

Example 3

The embodiment provides a method for repairing lithium aluminosilicate glass, which comprises the following steps:

(1) polishing two surfaces of the defective lithium aluminosilicate glass product by 5 microns respectively to remove scratch defects on the surface of the glass;

(2) and (3) inserting the polished lithium aluminosilicate glass into a toughening frame, then putting the toughened frame into a preheating furnace for preheating, starting to heat up from room temperature (about 25 ℃), heating to 380 ℃ within 40min, and preserving heat for 30min to finish preheating.

(3) Then putting the sample into first molten salt for strengthening, wherein the strengthening conditions are as follows: the temperature is 410 deg.C, the time is 30min, NaNO is in the first molten salt₃And KNO₃Respectively 60% and 40%.

(4) And then putting the reinforced sample into second molten salt for reinforcement, wherein the reinforcement conditions are as follows: the temperature is 410 deg.C, the time is 60min, KNO in the first molten salt₃The mass fraction of (b) is 100%.

(5) And transferring the glass to the air for natural cooling after the strengthening is finished.

Example 4

The embodiment provides a method for repairing lithium aluminosilicate glass, which comprises the following steps:

(1) polishing two surfaces of the defective lithium aluminosilicate glass product by 8 microns respectively to remove scratch defects on the surface of the glass;

(2) and (3) inserting the polished lithium aluminosilicate glass into a toughening frame, then putting the toughened frame into a preheating furnace for preheating, starting to heat up from room temperature (about 25 ℃), heating to 380 ℃ within 40min, and preserving heat for 30min to finish preheating.

(3) Then putting the sample into first molten salt for strengthening, wherein the strengthening conditions are as follows: the temperature is 410 deg.C, the time is 30min, NaNO is in the first molten salt₃And KNO₃Respectively 60% and 40%.

(4) And then putting the reinforced sample into second molten salt for reinforcement, wherein the reinforcement conditions are as follows: the temperature is 410 deg.C, the time is 70min, KNO in the first molten salt₃Is 100 percent.

(5) And transferring the glass to the air for natural cooling after the strengthening is finished.

Comparative example 1

The comparative example provides a method for repairing lithium aluminosilicate glass, comprising the steps of:

(1) polishing two surfaces of the defective lithium aluminosilicate glass product by 1 micron respectively to remove scratch defects on the surface of the glass;

(2) and (3) inserting the polished lithium aluminosilicate glass into a toughening frame, then putting the toughened frame into a preheating furnace for preheating, starting to heat up from room temperature (about 25 ℃), heating to 380 ℃ within 40min, and preserving heat for 30min to finish preheating.

(3) Then putting the sample into molten salt for strengthening, wherein the strengthening conditions are as follows: the temperature is 360 deg.C, the time is 30min, NaNO is in the molten salt₃And KNO₃The mass fraction of (A) is 99% and 1%.

(2) And transferring the glass to the air for natural cooling after the strengthening is finished.

Comparative example 2

The comparative example provides a method for repairing lithium aluminosilicate glass, comprising the steps of:

(1) polishing two surfaces of the defective lithium aluminosilicate glass product by 5 microns respectively to remove scratch defects on the surface of the glass;

(2) and (3) inserting the polished lithium aluminosilicate glass into a toughening frame, then putting the toughened frame into a preheating furnace for preheating, starting to heat up from room temperature (about 25 ℃), heating to 380 ℃ within 40min, and preserving heat for 30min to finish preheating.

(3) Then putting the sample into first molten salt for strengthening, wherein the strengthening conditions are as follows: the temperature is 360 deg.C, the time is 30min, NaNO is in the first molten salt₃And KNO₃Respectively 60% and 40%.

(4) And then putting the reinforced sample into second molten salt for reinforcement, wherein the reinforcement conditions are as follows: the temperature is 410 deg.C, the time is 60min, KNO in the first molten salt₃Is 100 percent.

(5) And transferring the glass to the air for natural cooling after the strengthening is finished.

Comparative example 3

The comparative example provides a method for repairing lithium aluminosilicate glass, comprising the steps of:

(1) polishing two surfaces of the defective lithium aluminosilicate glass product by 8 microns respectively to remove scratch defects on the surface of the glass;

(2) and (3) inserting the polished lithium aluminosilicate glass into a toughening frame, then putting the toughened frame into a preheating furnace for preheating, starting to heat up from room temperature (about 25 ℃), heating to 380 ℃ within 40min, and preserving heat for 30min to finish preheating.

(3) Then putting the sample into first molten salt for strengthening, wherein the strengthening conditions are as follows: the temperature is 430 ℃ and the time is 30min, and NaNO is in the first molten salt₃And KNO₃Respectively 60% and 40%.

(4) And then putting the reinforced sample into second molten salt for reinforcement, wherein the reinforcement conditions are as follows: the temperature is 410 deg.C, the time is 60min, KNO in the first molten salt₃Is 100 percent.

(5) And transferring the glass to the air for natural cooling after the strengthening is finished.

Examples 2 to 8 and comparative examples 1 to 7 were reinforced by the reinforcing method of example 1, except that the thickness of the polished part, the ratio of molten salt for reinforcement, and the reinforcing conditions were different, and the rest of preheating, cooling, and the like were the same as those of example 1.

The glasses of examples 1 to 8 and comparative examples 1 to 4 were subjected to CS, CS40, DOL _ K tests, and the test results are shown in Table 1.

TABLE 1 Return polishing strengthening parameters and stress Properties of the lithium silicate glasses of the examples

As can be seen from table 1, it is,

comparative example 1 compared with example 1 of the present invention, the one-time reinforcement is adopted, the reinforcement temperature is low, and the surfaces CS, CS40 and DOLK are all far lower than those of example 1, and the stress performance before back polishing can not be achieved.

Comparative example 2 compared with example 2 of the present invention, the first-step strengthening temperature was too low, and CS40 was lower than that of example 2, and the stress performance before back-polishing could not be achieved.

Comparative example 3 the first step strengthening temperature was too high relative to inventive example 2, resulting in a dimension exceeding the upper standard limit.

Comparative example 4 compared to inventive example 3, the first step strengthening time was too short and CS40 was much lower than in example 3, and the stress performance before back-polishing could not be achieved.

Comparative example 5 the first strengthening step was carried out for too long a time compared to example 3 of the present invention, resulting in the size exceeding the upper standard limit.

Comparative example 6 the second step strengthening temperature was too low and the strengthening time was too short compared to example 4 of the present invention, resulting in CS and DOLK being much lower than example 4 and failing to achieve the stress performance before back-polishing.

Comparative example 7 the second step strengthening temperature was too high and the strengthening time was too long for example 4 of the present invention, resulting in CS and CS40 being much lower than example 4 and failing to achieve the stress performance before back-polishing.

Finally, it should be noted that: the above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A method for repairing lithium aluminosilicate glass, comprising:

polishing the lithium aluminosilicate glass with the defects on the surface after chemical strengthening to eliminate the surface defects;

performing two times of chemical strengthening on the polished lithium aluminosilicate glass, wherein the two times of chemical strengthening comprise:

placing the lithium aluminosilicate glass in a solution containing Na⁺Or Na⁺And K⁺Strengthening in the first molten salt for 10-60 min at the strengthening temperature of 380-420 ℃; then placing the strengthened lithium aluminosilicate glass in a container containing K⁺Strengthening in the second salt bath for 20-90 min at a strengthening temperature of 380-430 ℃.

2. The method for repairing lithium aluminosilicate glass according to claim 1, wherein the mass fraction of the sodium salt in the first molten salt is 50 to 100% based on the mass of the first molten salt.

3. The method for repairing lithium aluminosilicate glass according to claim 2, wherein the mass fraction of the potassium salt in the first molten salt is 0 to 50% based on the mass of the first molten salt.

4. The repairing method of the lithium aluminosilicate glass according to claim 3, wherein the strengthening time of the lithium aluminosilicate glass in the first molten salt is 20-30 min, the strengthening temperature is 390-410 ℃, and the mass ratio of sodium salt to potassium salt in the first molten salt is 50-60% to 50-40%.

5. The method for repairing lithium aluminosilicate glass according to claim 1, wherein the second molten salt contains 100% by mass of a potassium salt.

6. The method for repairing lithium aluminosilicate glass according to claim 4, wherein the strengthening time of the lithium aluminosilicate glass in the second molten salt is 20-70 min, and the strengthening temperature is 390-410 ℃.

7. The method for repairing lithium aluminosilicate glass according to claim 1, wherein the Na is present in the two chemical strengthening steps⁺Derived from NaNO₃、Na₂CO₃、NaHCO₃、Na₃PO₄、Na₂SO₄And NaOH.

8. The method for repairing lithium aluminosilicate glass according to claim 1, wherein the K is chemically strengthened in the two chemical strengthening steps⁺Derived from KNO₃、K₂CO₃、KHCO₃、K₃PO₄、K₂SO₄And KOH.

9. The method for repairing lithium aluminosilicate glass according to claim 1, wherein the polishing step comprises polishing the lithium aluminosilicate glass on both sides, each polishing being 1 to 8 μm.

10. The method for repairing lithium aluminosilicate glass according to claim 1, further comprising a step of performing a preheating treatment on the lithium aluminosilicate glass after the polishing treatment and before the chemical strengthening treatment of the lithium aluminosilicate glass: and heating the lithium aluminosilicate glass to 380-420 ℃ within 30-60 min, and preserving the heat for 25-35 min.

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