Low-temperature reinforced high-alumina-silica glass and preparation method thereof

Abstract

The invention relates to the technical field of tempered glass, in particular to low-temperature tempered high-alumina-silica glass and a preparation method thereof. The low-temperature reinforced high-alumina silica glass is prepared from the following components in percentage by mass: 50.0% to 65.0% of S O < 2 >, 15.0% to 30.0% of Al < 2 > O < 3 >, 10.0% to 16.0% of Na < 2 > O, 0% to 8.0% of K < 2 > O, 0% to 8.0% of MgO and 2.0% to 10.0% of P < 2 > O < 5 >. The strengthening temperature of the high-alumina-silica glass is lower than the decomposition temperature of potassium nitrate, so that the service life of the strengthening salt can be prolonged, the glass is continuously strengthened, and the strength of the strengthened glass still meets the requirement.

Description

Technical Field

[0001] The present invention relates to the technical field of toughened glass, and more particularly to high-aluminum silicon glass with low-temperature toughening and a preparation method thereof. Background Art

[0002] Chemically strengthened glass is widely used in electronic products, automobiles, buildings and other fields due to its high strength and wear resistance. The commonly used types of chemically strengthened glass are primary strengthened glass and secondary strengthened glass.

[0003] Generally, soda-lime glass, medium-aluminum glass and high-aluminum glass will adopt primary strengthening. The principle of primary strengthening is that Na in the glass + and K in the salt + carry out ion exchange. The radius of Na + is and the radius of K + is Due to the "jamming" effect generated by the ion radius difference in the glass structure, a compressive stress layer of 10-45 μm is formed on the glass surface. Generally, lithium-aluminum glass adopts secondary strengthening. The first step of secondary strengthening is to immerse the glass in a molten salt with a NaNO 3 content higher than 50%. The principle is that Na in the molten salt + replaces Li on the glass surface + mainly. Since the radius of Na + is greater than the radius of Li + is a "jamming" effect is generated on the glass surface to form a surface compressive stress. The exchange efficiency is relatively high, and a stress layer of about 100 μm is obtained to achieve the strengthening effect. The second step of secondary strengthening is to immerse the glass in a molten salt with a KNO 3 content higher than 90%. The principle is that K in the molten salt + replaces Na on the glass surface + mainly. Since the radius of K + is greater than the radius of Na + is a "jamming" effect is generated on the glass surface to form a surface compressive stress. After the two steps are completed, a composite compressive stress layer is formed on the glass surface.

[0004] When traditional high-aluminum silicon glass is strengthened, it needs to be treated at a relatively high temperature (generally higher than 400 °C) for a long time to meet the requirements of stress > 700 MPa and stress layer depth > 35 μm. However, potassium nitrate used for strengthening begins to decompose into potassium nitrite and oxygen at 400 °C, and the ion exchange ability of KNO 2 is weaker than that of KNO 3, which in turn leads to poor strengthening effect. The decomposed oxygen will form bubbles in the molten salt, adhere to the glass surface, cause local stress concentration or microcracks, and also reduce the performance of the strengthened glass. At the same time, since potassium nitrate will decompose to form oxygen, it will cause the pressure in the strengthening furnace to become high. Therefore, intermittent gas discharge is required, which in turn will lead to production interruption and continuous production cannot be carried out. And because strengthening is a process that strengthened glass must go through, whether there is glass being strengthened or not, the temperature of the furnace always remains at a relatively high temperature (>400 °C), increasing energy consumption while the strengthening salt is constantly lost, affecting the strengthening quality. In summary, it can be seen that the existing high-aluminum silicon glass has caused many problems due to the too high strengthening temperature (>400 °C).

[0005] In view of this, the present invention is specifically proposed. Summary of the Invention

[0006] The purpose of the present invention is to provide a low-temperature strengthened high-aluminum silicon glass and its preparation method. The strengthening temperature of this low-temperature strengthened high-aluminum silicon glass is lower than the decomposition temperature of potassium nitrate, which can improve the service life of the strengthening salt, strengthen continuously, and the strength of the strengthened glass still meets the requirements.

[0007] The present invention is implemented as follows:

[0008] In the first aspect, an embodiment of the present invention provides a low-temperature strengthened high-aluminum silicon glass, which, in terms of mass percentage, includes the following components: 50.0% - 65.0% of SiO 2 , 15.0% - 30.0% of Al 2 O 3 , 10.0% - 16.0% of Na 2 O, 0% - 8.0% of K 2 O, 0% - 8.0% of MgO, and 2.0% - 10.0% of P 2 O 5 .

[0009] In an optional embodiment, in terms of mass percentage, it includes the following components: 54.0% - 63.0% of SiO 2 , 17.0% - 28.0% of Al 2 O 3 , 11.0% - 14.0% of Na 2 O, 1.0% - 5.0% of K 2 O, 0% - 5.0% of MgO, and 2.0% - 8.0% of P 2 O 5 .

[0010] In an optional embodiment, in terms of mass percentage, it includes the following components: 56.0% - 62.0% of SiO 2, 19.0% to 23.0% Al 2 O 3 , 11.2% to 13.5% Na 2 O, 1.8% to 3.0% K 2 O, 0% to 3.0% MgO and 3.0% to 5.5% P 2 O 5 .

[0011] In an alternative embodiment, the content of Al 2 O 3 + P 2 O 5 + K 2 O is 21% to 40%.

[0012] In an alternative embodiment, the content of Al 2 O 3 + P 2 O 5 + K 2 O is 25 to 39 wt%.

[0013] In an alternative embodiment, the surface stress layer depth of the low-temperature strengthened high-aluminum silicon glass is more than 35 μm.

[0014] In an alternative embodiment, the surface stress of the low-temperature strengthened high-aluminum silicon glass is more than 800 MPa.

[0015] Second, the embodiments of the present invention provide a method for preparing the above-mentioned low-temperature strengthened high-aluminum silicon glass, including: melting, casting and annealing the raw materials for forming the low-temperature strengthened high-aluminum silicon glass to form a raw glass, and then performing primary strengthening on the raw glass.

[0016] In an alternative embodiment, the conditions for primary strengthening include: the strengthening salt is 100% KNO 3 , the strengthening temperature is below 400 °C, and the strengthening time is 4 to 6 hours.

[0017] In an alternative embodiment, the conditions for primary strengthening include: the strengthening salt is 100% KNO 3 , the strengthening temperature is 350 °C to 390 °C, preferably 350 °C to 375 °C, and the strengthening time is 4 to 6 hours.

[0018] The present invention has the following beneficial effects: (1) By selecting specific raw materials and their ratios, the formed high-aluminum silicon glass can be strengthened with molten potassium nitrate at low temperature. This strengthening temperature is lower than the decomposition temperature of potassium nitrate, so that the strengthening salt potassium nitrate will not decompose. Consequently, the strengthening furnace will not interrupt exhaust due to the oxygen generated by the decomposition of potassium nitrate, and continuous production can be achieved.

[0019] (2) Low-temperature strengthening, the strengthening salt will not decompose, thus prolonging the service life of the strengthening salt. There is no need to supplement the consumed strengthening salt excessively, reducing the production cost.

[0020] (3) With the same strengthening time, even with low-temperature strengthening, the strength of the obtained strengthened glass is still relatively high, even higher than the performance of general once-strengthened glass. Specific implementation manners

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be described clearly and completely below. For those not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. For reagents or instruments without indicating the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0022] In a first aspect, an embodiment of the present invention provides a high-aluminum-silicon glass with low-temperature strengthening. In terms of mass percentage, it includes the following components: 50.0% - 65.0% of SiO 2 , 15.0% - 30.0% of Al 2 O 3 , 10.0% - 16.0% of Na 2 O, 0% - 8.0% of K 2 O, 0% - 8.0% of MgO, and 2.0% - 10.0% of P 2 O 5 .

[0023] In the embodiment of the present invention, by optimizing the raw materials for forming the high-aluminum-silicon glass and their ratios, the strengthening temperature is significantly reduced. Specifically, it is much lower than the decomposition temperature of the strengthening salt potassium nitrate 100%. Subsequently, it can effectively prevent the decomposition of potassium nitrate, extend the service life of the strengthening salt, and at the same time, ensure the continuity of production without interrupting the exhaust of the strengthening furnace. Also, even with low-temperature strengthening, the strength of the obtained strengthened glass is still excellent.

[0024] Specifically, the dosage of SiO 2 is 50.0%, 51.0%, 52.0%, 53.0%, 54.0%, 55.0%, 56.%, 57.0%, 58.0%, 59.0%, 60.0%, 61.0%, 62.0%, 63.0%, 64.0%, 65.0% or any value between 50.0% - 65.0%, for example, preferably 54.0% - 63.0%, more preferably 56.0% - 62.0%.

[0025] Al 2 O 3 has a strong ability to compete for free oxygen and preferentially forms aluminum-oxygen tetrahedrons [AlO4 , repair the network break, form a unified network with silicon-oxygen tetrahedrons, strengthen the glass structure. Since the volume of aluminum-oxygen tetrahedrons is larger than that of silicon-oxygen tetrahedrons, the existence of aluminum-oxygen tetrahedrons will cause the voids in the glass structure to become larger, which is beneficial to the activity of alkali metal ions. Therefore, it also has the effect of accelerating the ion exchange process.

[0026] Al 2 O 3 The dosage of is 15.0%, 16.0%, 17.0%, 18.0%, 19.0%, 20.0%, 21.0%, 22.0%, 23.0%, 24.0%, 25.0%, 26.0%, 27.0%, 28.0%, 29.0%, 30.0% or any value between 15.0% and 30.0%. For example, it is preferably 17.0% - 28.0%, and more preferably 19.0% - 23.0%.

[0027] Na 2 The dosage of O is 10.0%, 11.0%, 12.0%, 13.0%, 14.0%, 15.0%, 16.0% or any value between 10.0% and 16.0%. For example, it is preferably 11.0% - 14.0%, and more preferably 11.2% - 13.5%.

[0028] K 2 The dosage of O is 0.0%, 1.0%, 2.0%, 3.0%, 4.0%, 5.0%, 6.0%, 7.0%, 8.0% or any value between 0% and 8.0%. For example, it is preferably 1.0% - 5.0%, and more preferably 1.8% - 3.0%.

[0029] In the glass containing Na 2 O and K 2 O, there are 4 transition modes for K in the glass: ① Transition from the K + position to the vacancy of the adjacent Na + ; ② Transition from the K + position to the vacancy of the adjacent K + ; ③ Transition from the Na + position to the vacancy of the adjacent Na + ; ④ Transition from the Na + position to the vacancy of the adjacent K + . Only the first one will generate compressive stress due to the jamming effect. During strengthening, in addition to the K + in the molten salt will transition to the Na + position in the glass, the K + in the glass will also transition to the Na + position deeper in the glass, and the K + in the glass will also transition to the Na +At this position, potassium ions in all glasses will also increase the depth of the strengthened stress layer of the glass.

[0030] The dosage of MgO is 0.0%, 1.0%, 2.0%, 3.0%, 4.0%, 5.0%, 6.0%, 7.0%, 8.0% or any value between 0% and 8.0%, for example, preferably 0% to 5.0%, more preferably 0% to 3.0%.

[0031] P 2 O 5 The dosage of is 2.0%, 3.0%, 4.0%, 5.0%, 6.0%, 7.0%, 8.0%, 9.0%, 10.0% or any value between 2.0% and 10.0%, for example, preferably 2.0% to 8.0%, more preferably 3.0% to 5.5%.

[0032] P 2 O 5 As the matrix constituting the glass, it can form glass alone. Its addition can enhance the chemical stability and mechanical properties of the glass. At the same time, it is also a good solvent, which can greatly reduce the melting temperature of the glass and is also beneficial to the vitrification process. P 2 O 5 has a certain depolymerization effect on the structure of the large anionic group of glass silicon oxygen, accelerates the ion exchange process, and both the ion exchange depth and the stress layer depth of the glass increase with the increase of the content of P 2 O 5 content.

[0033] Al 2 O 3 +P 2 O 5 +K 2 The content of O is 21% to 40%. For example, it is 21%, 25%, 30%, 35%, 40% or any value between 21% and 40%, preferably 25 to 39 wt%.

[0034] Furthermore, the surface stress layer depth of the high-aluminum silicon glass strengthened at low temperature is more than 35 μm. The surface stress of the high-aluminum silicon glass strengthened at low temperature is more than 800 MPa. It can be seen that the high-aluminum silicon glass provided by the embodiments of the present invention has excellent strength and can meet the use requirements. Then, the high-aluminum silicon glass strengthened at low temperature provided by the embodiments of the present invention can be widely used in the fields of mobile phones, computers, tablets, wearables, smart homes, vehicle covers, front and rear windshields of cars, side windows, sunroofs, rearview mirrors, lidar, etc.

[0035] In a second aspect, an embodiment of the present invention provides a method for preparing a high-aluminum silicon glass strengthened at low temperature, including: melting, casting, and annealing the raw materials for forming the high-aluminum silicon glass strengthened at low temperature to form a raw glass, and then performing primary strengthening on the raw glass.

[0036] The specific steps are as follows:

[0037] (1) Preparation of the original glass:

[0038] Weigh the raw materials according to the component ratios, mix the mixed raw materials evenly in a mixing machine, then pour them into a platinum crucible for melting and fusing. Pour the molten glass liquid into a metal mold, and put the glass into an annealing furnace for precision annealing and cooling. For example, the annealing temperature is 500 °C, and the holding time at this temperature is 60 min, and then it is naturally cooled to 100 °C. Cut and polish the cooled glass block to obtain a transparent flat original glass. For example, the thickness of the transparent flat original glass is 0.6 mm.

[0039] Then, use the commonly used CNC (Computer Numerical Control Technology) in this field to process the original glass plate into a sample of 155 mm × 73 mm × 0.6 mm after grinding the edges, and then use a microscope to check its edges to ensure that the edge chipping size is not greater than 35 μm.

[0040] (2) Chemically strengthened glass

[0041] Perform strengthening treatments on the glass samples processed in the above step (1) respectively. Specifically, insert the glass samples into a toughening rack and then put them into a preheating furnace for preheating. For example, the preheating starts from room temperature and rises to 250 °C within 30 min, and the preheating is completed after holding for 30 min. Then put the samples into a molten liquid of 100% pure KNO 3 for the first chemical strengthening. Specifically, the conditions for the first strengthening include: the strengthening temperature is below 400 °C, such as temperatures below 400 °C like 350 °C, 355 °C, 360 °C, 365 °C, 370 °C, 375 °C, 380 °C, 390 °C, etc., preferably 350 °C - 390 °C, more preferably 350 °C - 375 °C. The strengthening time is 4 - 6 hours, such as any value between 4 - 6 hours like 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, etc.

[0042] After the strengthening is completed, perform cooling. For example, transfer it to a preheating furnace at a temperature of 250 °C, turn off the heating power supply of the preheating furnace, and take out the sample after it is naturally cooled and annealed to below 100 °C in the furnace.

[0043] The features and properties of the present invention will be further described in detail below in conjunction with the embodiments.

[0044] Examples 1 - 14 and Comparative Examples 1 - 5

[0045] Examples 1 - 14 and Comparative Examples 1 - 5 respectively provide a high - alumina - silica glass, and its composition is shown in Table 1.

[0046] Example 1 provides a method for preparing high-aluminum silicon glass, including:

[0047] Step 1: According to the component ratio in Table 1, mix the raw materials proportionally and mix them evenly in a mixing machine.

[0048] Step 2: Pour the mixed raw materials into a platinum crucible and melt them in a high-temperature furnace.

[0049] Step 3: Pour the molten glass liquid into a metal mold, put the glass into an annealing furnace for precision annealing and cooling. The annealing temperature is 500 °C, and the holding time at this temperature is 60 min, and then it is naturally cooled to 100 °C.

[0050] Step 4: Slice and polish the cooled glass block to obtain a transparent flat original glass with dimensions of 155.6×73.6×0.6 mm.

[0051] Step 5: Then, use the commonly used CNC (Computer Numerical Control Technology) in the art to grind the original glass plate to make a sample with dimensions of 155×73×0.6 mm, and then use a microscope to check its edge to ensure that the edge chipping size is not greater than 35 μm.

[0052] Step 6: Insert the glass sample into a tempering rack, and then put it into a preheating furnace for preheating. The preheating starts from room temperature and rises to 250 °C within 30 min, and the preheating is completed after holding for 30 min.

[0053] Step 7: Put the sample into the molten liquid of pure KNO 3 for chemical strengthening for a certain period of time. Among them, the strengthening conditions are shown in Table 1. After the strengthening is completed, transfer it to a preheating furnace at a temperature of 250 °C, turn off the heating power of the preheating furnace, and take out the sample after it is naturally cooled and annealed in the furnace to below 100 °C. After the sample is cooled to room temperature, clean and dry it.

[0054] Step 8: After the glass is prepared, conduct performance testing.

[0055] Examples 2-14 and Comparative Examples 1-5 all provide a method for preparing high-aluminum silicon glass. This preparation method is basically the same as the preparation method provided in Example 1, except that the original composition, proportioning, or strengthening conditions for forming the high-aluminum silicon glass are different. The specific conditions are shown in Table 1.

[0056] Table 1 Composition and strengthening conditions of high-aluminum silicon glass in Examples 2-14 and Comparative Examples 1-5

[0057]

[0058]

[0059] As can be seen from Table 1, (1) comparing the examples with Comparative Examples 1 and 5, it can be seen that if the raw material composition provided in the examples of the present invention is changed, for example, a certain component is reduced or a certain component is increased, the strengthening effect is poor during low-temperature strengthening.

[0060] (2) Comparing the examples with Comparative Examples 2-4, it can be seen that if the raw material ratio passed in the examples of the present invention is changed so that the raw material ratio is not within the range of the examples of the present invention, the strength of the strengthened glass formed after low-temperature strengthening is not good.

[0061] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A low temperature strengthened high alumina silicate glass, characterized in that: Calculated in mass percentage, it includes the following composition: 50.0% to 65.0% SiO2, 15.0% to 30.0% Al2O3, 10.0% to 16.0% Na2O, 0% to 8.0% K2O, 0% to 8.0% MgO and 2.0% to 10.0% P2O5.

2. The low temperature strengthened high alumina silicate glass according to claim 1, characterized in that: Calculated in mass percentage, it includes the following compositions: 54.0% to 63.0% SiO2, 17.0% to 28.0% Al2O3, 11.0% to 14.0% Na2O, 1.0% to 5.0% K2O, 0% to 5.0% MgO and 2.0% to 8.0% P2O5.

3. The low temperature strengthened high alumina silicate glass according to claim 1, characterized in that: Calculated in mass percentage, it includes the following compositions: 56.0% to 62.0% SiO2, 19.0% to 23.0% Al2O3, 11.2% to 13.5% Na2O, 1.8% to 3.0% K2O, 0% to 3.0% MgO and 3.0% to 5.5% P2O5.

4. The low temperature strengthened high alumina silicate glass according to any one of claims 1 to 3, characterized in that: The content of Al2O3+P2O5+K2O is 21%~40%.

5. The low temperature strengthened high alumina silicate glass according to any one of claims 1 to 3, characterized in that: The content of Al2O3+P2O5+K2O is 25~39wt%.

6. The low temperature strengthened high alumina silicate glass according to any one of claims 1 to 3, characterized in that: The surface stress layer of the low temperature strengthened high alumina silicate glass is more than 35 μm deep.

7. The low temperature strengthened high alumina silicate glass according to any one of claims 1 to 3, characterized in that: The surface stress of the low temperature strengthened high alumina silicate glass is above 800 MPa.

8. A method for preparing low temperature strengthened high alumina-silica glass according to claim 1, characterized in that: include: The raw materials for forming the low temperature strengthened high alumina-silicate glass are melted, cast and annealed to form raw glass, and then the raw glass is strengthened once.

9. The preparation method according to claim 8, characterized in that: The conditions for primary strengthening include: strengthening salt is 100% KNO3, strengthening temperature is below 400°C, and strengthening time is 4 to 6 hours.

10. The preparation method according to claim 8, characterized in that: The conditions for primary strengthening include: strengthening salt is 100% KNO3, strengthening temperature is 350°C to 390°C, preferably 350°C to 375°C, and strengthening time is 4 to 6 hours.

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