A pressure-resistant deep-sea transparent glass-ceramic and its preparation method

Abstract

The present invention provides a method for preparing pressure-resistant deep-sea transparent glass-ceramics. By adjusting the glass formula, the method controls the degree of aluminum crystallization from the glass phase to the microcrystalline phase, thereby controlling the ion exchange channels. By improving the ion exchange formula and utilizing the large channels provided by aluminum oxide tetrahedrons, the ion exchange depth of the glass-ceramics can be greatly increased. By improving the glass-ceramics and ion exchange formulas, the stress relaxation and thermal fatigue problems caused by conventional secondary strengthening formulas can be effectively avoided. The present invention also provides pressure-resistant deep-sea transparent glass-ceramics.

Description

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on June 6, 2023, with application number 2023106623113 and invention name “A pressure-resistant deep-sea transparent microcrystalline glass and its preparation method”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present invention belongs to the technical field of ocean exploration, and in particular relates to a pressure-resistant deep-sea transparent microcrystalline glass and a preparation method thereof. Background Art

[0003] The pressure-resistant deep-sea transparent glass windows used for deep-sea manned exploration today have very high performance requirements in terms of pressure resistance, bending resistance, corrosion resistance, and light transmittance. In particular, the pressure resistance is much stronger than that of ordinary glass windows. Starting from the sea level, the window needs to withstand an increase of 1000Pa in seawater pressure for every meter of descent. When a manned submersible descends to the deep sea, the pressure it withstands may reach tens of MPa or even hundreds of MPa. The window needs to be able to withstand the pressure and maintain a clear line of sight.

[0004] Glass-ceramics is a new type of modern material with performance superior to that of ordinary glass. The existing ion exchange methods for glass-ceramics in China are mostly used in small electronic devices such as mobile phones, and are rarely used in large-area ion-strengthening places such as windows. Especially in the face of deep seas of 10,000 meters or more, the performance of glass produced by conventional small-area ion-strengthening processes can no longer meet the requirements for use in deep-sea environments, and can no longer provide high protection for the personal safety of manned probes. Summary of the Invention

[0005] The purpose of the present invention is to provide a pressure-resistant deep-sea transparent microcrystalline glass and a preparation method thereof. The preparation method of the present invention has a better strengthening effect on high-aluminum, low-lithium microcrystalline glass, and the prepared microcrystalline glass meets the requirements for use in deep-sea environments.

[0006] The present invention provides a method for preparing pressure-resistant deep-sea transparent glass-ceramics, comprising the following steps:

[0007] A) uniformly mixing the raw materials and melting and homogenizing them to obtain molten glass;

[0008] The raw materials include the following components by mass fraction:

[0009]

[0010] B) pouring the glass liquid into a mold to form the mold, and then annealing the formed glass to obtain ordinary glass;

[0011] C) subjecting ordinary glass to a nucleation heat treatment and a crystallization heat treatment in sequence to obtain glass-ceramics;

[0012] D) preheating the glass-ceramics for the first time and placing it in a first molten salt for the first chemical strengthening;

[0013] The first molten salt comprises 28-30 wt% of sodium nitrate, 59-61 wt% of potassium nitrate, 0.02-0.03 wt% of potassium silicate, 0.02-0.03 wt% of sodium silicate, 0.2-0.3 wt% of aluminum oxide, 9-12 wt% of copper chloride, and 0.01-0.1 wt% of cerium oxide;

[0014] E) preheating the glass-ceramics after the first chemical strengthening for a second time, placing the glass-ceramics in a second molten salt, and performing a second chemical strengthening to obtain a compression-resistant deep-sea transparent glass-ceramics;

[0015] The second molten salt includes 93-96 wt% of potassium nitrate, 0.3-0.6 wt% of potassium hydroxide, 0.02-0.03 wt% of potassium silicate, 2-5 wt% of diatomaceous earth, 0.02-0.03 wt% of lanthanum oxide, and 1.4-1.5 wt% of potassium carbonate.

[0016] Preferably, the temperature of the melt homogenization is 1580-1650° C., and the holding time of the melt homogenization is 3-4 hours.

[0017] Preferably, the annealing temperature is 600-750° C.; and the annealing holding time is 1-2 hours.

[0018] Preferably, the temperature of the nucleation heat treatment is 680-720° C., and the holding time of the nucleation heat treatment is 2-4 hours;

[0019] The temperature of the crystallization heat treatment is 780-850° C., and the holding time of the crystallization heat treatment is 2-4 hours.

[0020] Preferably, the temperature of the first preheating is 300-400° C.; and the holding time of the first preheating is 30-40 minutes.

[0021] Preferably, the temperature of the first chemical strengthening is 450-550° C., and the holding time of the first chemical strengthening is 1-5 hours.

[0022] Preferably, the temperature of the second preheating is 500-530° C.; and the insulation time of the second preheating is 2-4 hours.

[0023] Preferably, the temperature of the second chemical strengthening is 400-500° C., and the holding time of the second chemical strengthening is 1-5 hours.

[0024] Preferably, an ion sieve is added during the first chemical strengthening process to absorb Li + .

[0025] The present invention provides pressure-resistant deep-sea transparent microcrystalline glass prepared by the preparation method described above.

[0026] The invention provides a method for preparing pressure-resistant deep-sea transparent micro-ceramic glass, comprising the following steps: A) uniformly mixing raw materials, melting and homogenizing the mixture, and obtaining glass liquid; the raw materials comprising the following components by mass fraction: 50-60 wt% of silicon oxide, 24-30 wt% of aluminum oxide, 2-5 wt% of sodium oxide, 2-6 wt% of lithium oxide, 2-8 wt% of zinc oxide, 4-6 wt% of titanium oxide, 0.5-4 wt% of zirconium oxide, 0.5-4 wt% of germanium oxide, 0-3 wt% of yttrium oxide, 0-3 wt% of phosphorus pentoxide, and 0-3 wt% of boron trioxide; B) pouring the glass liquid into a mold, forming the molded glass, and then annealing the formed glass to obtain ordinary glass; C) sequentially performing nucleation heat treatment and crystallization heat treatment on the ordinary glass to obtain micro-ceramic glass; D) preheating the micro-ceramic glass for the first time and placing it in a first melting pot. The first molten salt comprises 28-30 wt% of sodium nitrate, 59-61 wt% of potassium nitrate, 0.02-0.03 wt% of potassium silicate, 0.02-0.03 wt% of sodium silicate, 0.2-0.3 wt% of aluminum oxide, 9-12 wt% of copper chloride, and 0.01-0.1 wt% of cerium oxide; E) the glass-ceramics after the first chemical strengthening is preheated for a second time and then placed in a second molten salt for a second chemical strengthening to obtain compression-resistant deep-sea transparent glass-ceramics; the second molten salt comprises 93-96 wt% of potassium nitrate, 0.3-0.6 wt% of potassium hydroxide, 0.02-0.03 wt% of potassium silicate, 2-5 wt% of diatomaceous earth, 0.02-0.03 wt% of lanthanum oxide, and 1.4-1.5 wt% of potassium carbonate. The present invention needs to strengthen a new type of high-aluminum, low-lithium glass-ceramics whose main crystal phases are zinc-aluminum spinel and zirconium dioxide. Since the formula of the glass-ceramics contains a high aluminum content (Al>24wt%), aluminum replaces silicon to form aluminum-oxygen tetrahedrons, which expands the exchange channels. Although it can provide a larger channel for ion exchange, the conventional two-step ion strengthening process method cannot optimize the strengthening effect of this new type of high-aluminum, low-lithium glass-ceramics, and the conventional secondary ion exchange method to strengthen the high-aluminum glass-ceramics will cause stress relaxation and thermal fatigue problems in the high-aluminum glass-ceramics. From the crystal phase, since the high-aluminum, low-lithium glass-ceramics is based on zinc-aluminum spinel and zirconium oxide as the main crystal phases, the present invention controls the degree of crystallization of aluminum from the glass phase to the microcrystalline phase by adjusting the glass formula, thereby controlling the ion exchange channels. By improving the ion exchange formula and utilizing the large channels provided by the aluminum-oxygen tetrahedrons, the ion exchange depth of the glass-ceramics can be greatly increased. By improving the formula of the glass-ceramics and the ion exchange formula, the stress relaxation and thermal fatigue problems caused by the general secondary strengthening formula can be well avoided. DETAILED DESCRIPTION

[0027] The present invention provides a method for preparing pressure-resistant deep-sea transparent glass-ceramics, comprising the following steps:

[0028] A) uniformly mixing the raw materials and melting and homogenizing them to obtain molten glass;

[0029] The raw materials include the following components by mass fraction:

[0030]

[0031] B) pouring the glass liquid into a mold to form the mold, and then annealing the formed glass to obtain ordinary glass;

[0032] C) subjecting ordinary glass to a nucleation heat treatment and a crystallization heat treatment in sequence to obtain glass-ceramics;

[0033] D) preheating the glass-ceramics for the first time and placing it in a first molten salt for the first chemical strengthening;

[0034] The first molten salt comprises 28-30 wt% of sodium nitrate, 59-61 wt% of potassium nitrate, 0.02-0.03 wt% of potassium silicate, 0.02-0.03 wt% of sodium silicate, 0.2-0.3 wt% of aluminum oxide, 9-12 wt% of copper chloride, and 0.01-0.1 wt% of cerium oxide;

[0035] E) After the first chemical strengthening, the glass-ceramics is preheated for a second time and then placed in a second molten salt for a second chemical strengthening to obtain a compressive deep-sea transparent glass-ceramics.

[0036] The second molten salt includes 93-96 wt% of potassium nitrate, 0.3-0.6 wt% of potassium hydroxide, 0.02-0.03 wt% of potassium silicate, 2-5 wt% of diatomaceous earth, 0.02-0.03 wt% of lanthanum oxide, and 1.4-1.5 wt% of potassium carbonate.

[0037] In the present invention, in the preparation raw materials, the mass fraction of silicon oxide is preferably 50-60wt%, more preferably 52-58wt%, such as 50wt%, 51wt%, 52wt%, 53wt%, 54wt%, 55wt%, 56wt%, 57wt%, 58wt%, 59wt%, 60wt%, preferably a range value with any of the above values ​​as the upper or lower limit; the mass fraction of aluminum oxide is preferably 24-30wt%, more preferably 25-28wt%, such as 24wt%, 25wt%, 26wt%, 27wt%, 28wt%, 29wt%, 30wt%, preferably above The above arbitrary numerical values ​​are range values ​​with upper or lower limits; the mass fraction of sodium oxide is preferably 2-5wt%, preferably 3-4wt%, such as 2wt%, 3wt%, 4wt%, 5wt%, preferably a range value with the above arbitrary numerical values ​​as upper or lower limits; the mass fraction of lithium oxide is preferably 2-6wt%, preferably 3-5wt%, such as 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, preferably a range value with the above arbitrary numerical values ​​as upper or lower limits; the mass fraction of zinc oxide is preferably 2-8wt%, preferably 3-7wt%, such as 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, preferably a range value with any of the above values ​​as the upper or lower limit; the mass fraction of titanium oxide is preferably 4-6wt%, such as 4wt%, 5wt%, 6wt%, preferably a range value with any of the above values ​​as the upper or lower limit; the mass fraction of zirconium oxide is preferably 0.5-4wt%, more preferably 1-3wt%, such as 0.5wt%, 1wt%, 2wt%, 3wt%, 4wt%, preferably a range value with any of the above values ​​as the upper or lower limit; the mass fraction of germanium oxide is preferably 0.5-4wt%, more preferably 1-3wt%, such as 0.5wt%, 1wt%, 2wt%, 3wt%, 4wt%, preferably a range value with the above arbitrary numerical value as the upper or lower limit; the mass fraction of yttrium oxide is preferably 0-3wt%, such as 0wt%, 1wt%, 2wt%, 3wt%, preferably a range value with the above arbitrary numerical value as the upper or lower limit; the mass fraction of phosphorus pentoxide is preferably 0-3wt%, such as 0wt%, 1wt%, 2wt%, 3wt%, preferably a range value with the above arbitrary numerical value as the upper or lower limit; the mass fraction of boron trioxide is preferably 0-3wt%, such as 0wt%, 1wt%, 2wt%, 3wt%, preferably a range value with the above arbitrary numerical value as the upper or lower limit.

[0038] The invention weighs the raw materials according to the above ratio and mixes them, puts the mixed materials into a corundum crucible, and melts and homogenizes them in a high-temperature electric furnace to obtain glass liquid.

[0039] In the present invention, the temperature of the melt homogenization is preferably 1580-1650°C, more preferably 1590-1630°C, such as 1580°C, 1590°C, 1600°C, 1610°C, 1620°C, 1630°C, 1640°C, 1650°C, preferably a range value with any of the above values ​​as the upper or lower limit; the holding time of the melt homogenization is preferably 3-4 hours, and the heating rate of the melt homogenization is preferably 1-5°C / min, more preferably 3-4°C / min.

[0040] After obtaining the glass liquid, the present invention pours the melted glass liquid into a cast iron mold and statically forms the glass. The cooled and formed glass is then placed in a muffle furnace at a predetermined temperature for annealing. After cooling, the glass is taken out to obtain ordinary glass.

[0041] In the present invention, the annealing temperature is preferably 600-750°C, more preferably 650-700°C, such as 600°C, 610°C, 620°C, 630°C, 640°C, 650°C, 660°C, 670°C, 680°C, 690°C, 700°C, 710°C, 720°C, 730°C, 740°C, 750°C, preferably a range value with any of the above values ​​as the upper or lower limit; the annealing holding time is preferably 1-2 hours.

[0042] The ordinary glass obtained after annealing is cleaned and polished, and then placed in a box-type silicon carbon rod resistance furnace for a two-step heat treatment, wherein the two-step heat treatment sequentially includes a nucleation heat treatment and a crystallization heat treatment.

[0043] In the present invention, the temperature of the nucleation heat treatment is preferably 680-720°C, more preferably 690-710°C, such as 680°C, 690°C, 700°C, 710°C, 720°C, preferably a range value with any of the above values ​​as the upper or lower limit; the holding time of the nucleation heat treatment is preferably 2-4 hours, more preferably 2-3 hours; the heating rate of the nucleation heat treatment is preferably 3-10°C / min, more preferably 5-6°C / min.

[0044] In the present invention, the temperature of the crystallization heat treatment is preferably 780-850°C, more preferably 800-820°C, such as 780°C, 790°C, 800°C, 810°C, 820°C, 830°C, 840°C, 850°C, preferably a range value with any of the above values ​​as the upper or lower limit; the holding time of the crystallization heat treatment is preferably 2-4 hours, more preferably 2-3 hours; the heating rate of the crystallization heat treatment is preferably 3-10°C / min, more preferably 5-6°C / min.

[0045] After the crystallization heat treatment is completed, the product is cooled to room temperature, taken out, cleaned and dried to obtain microcrystalline glass.

[0046] The obtained microcrystalline glass is placed in a preheating furnace and heated for the first preheating, and then the glass after the first preheating is placed in a first molten salt for the first chemical strengthening.

[0047] In the present invention, the temperature of the first preheating is preferably 300-400°C, more preferably 320-380°C, such as 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, 360°C, 370°C, 380°C, 390°C, 400°C, preferably a range value with any of the above values ​​as the upper or lower limit; the holding time of the first preheating is preferably 30-40 min; the heating rate of the first preheating is preferably 8-12°C / min, more preferably 9-10°C / min.

[0048] In the present invention, the first molten salt preferably includes 28-30wt% of sodium nitrate, 59-61wt% of potassium nitrate, 0.02-0.03wt% of potassium silicate, 0.02-0.03wt% of sodium silicate, 0.2-0.3wt% of aluminum oxide, 9.65-11.65wt% of copper chloride, and 0.01-0.1wt% of cerium oxide.

[0049] In the present invention, the temperature of the first chemical strengthening is preferably 450-550°C, more preferably 180-530°C, such as 450°C, 460°C, 470°C, 480°C, 490°C, 500°C, 510°C, 520°C, 530°C, 540°C, 550°C, preferably a range value with any of the above values ​​as the upper or lower limit; the holding time of the first chemical strengthening is preferably 1-5 hours, more preferably 3-4 hours.

[0050] The first chemical strengthening is mainly Na + Li replacement + Therefore, Li in the molten salt + The content increases rapidly. In the present invention, it is preferred to add an ion sieve to the first molten salt to absorb the Li + The mass of the ion sieve added to the molten salt needs to be less than the mass of the microcrystalline glass, usually 1 to 10 wt% of the mass of the molten salt used, preferably 3 to 8 wt%, and more preferably 5 to 6 wt%.

[0051] The present invention can add the glass-ceramics and the ion sieve into the molten salt one after the other, and screen the glass-ceramics during the first chemical strengthening process to ensure its exchange efficiency; or, put the ion sieve into the used first molten salt, that is, the molten salt with a significantly slow ion exchange rate or inactive molten salt, and absorb the Li in the molten salt. + The aspiration time is 15 to 20 hours.

[0052] In the present invention, the main components of the ion sieve include 40-45 mol% of functional alkali metal oxide sodium oxide, preferably 41-44 mol%, more preferably 42-43 mol%; silicon oxide and aluminum oxide constituting the structural skeleton of the ion sieve, wherein the silicon oxide content is 40-45 mol%, preferably 41-44 mol%, more preferably 41-42 mol%, and the aluminum oxide content is 10-15 mol%, preferably 11-14 mol%, more preferably 12-13 mol%; and other metal oxides magnesium oxide and calcium oxide, wherein the magnesium oxide content is 1-3 mol%, preferably 2 mol%, and the calcium oxide content is 1-3 mol%, preferably 2 mol%, to ensure that the ion sieve has a certain high temperature stability.

[0053] By adding a foaming agent, the ion sieve forms a porous structure, increasing the absorption surface area and accelerating the absorption rate. Alkali metal ions combine with the chain-like network structure to form three-dimensional channels. The ion sieve utilizes the high temperature of the molten salt. Due to the difference in impurity ion content at the solid-liquid interface, the impurity ions are absorbed through solid-phase diffusion. The three-dimensional ion channels of the ion sieve are more selective for the absorption of smaller lithium ions.

[0054] After completing the first chemical strengthening, the present invention places the microcrystalline glass after the first strengthening in a muffle furnace for a second preheating heat treatment, and then places the heat-treated microcrystalline glass in a second molten salt for a second chemical strengthening to obtain pressure-resistant deep-sea transparent microcrystalline glass.

[0055] In the present invention, the temperature of the second preheating is preferably 500-530° C., more preferably 510-520° C.; the holding time of the second preheating is preferably 2-4 hours, more preferably 2-3 hours.

[0056] In the present invention, the second molten salt preferably includes 93-96 wt% potassium nitrate, 0.3-0.6 wt% potassium hydroxide, 0.02-0.03 wt% potassium silicate, 2-5 wt% diatomaceous earth, 0.02-0.03 wt% lanthanum oxide, and 1.4-1.5 wt% potassium carbonate.

[0057] In the present invention, the temperature of the second chemical strengthening is preferably 400-500°C, preferably 420-480°C, such as 400°C, 410°C, 420°C, 430°C, 440°C, 450°C, 460°C, 470°C, 480°C, 490°C, 500°C, preferably a range value with any of the above values ​​as the upper or lower limit; the holding time of the second chemical strengthening is 1-5 hours, preferably 2-3 hours.

[0058] The present invention also provides a pressure-resistant deep-sea transparent microcrystalline glass, which is prepared according to the preparation method described above.

[0059] By improving the glass-ceramics formula, the present invention can produce a high-aluminum, low-lithium glass-ceramics with zinc-aluminum spinel and zirconium dioxide as the main crystalline phases. However, conventional two-step ion strengthening processes cannot achieve optimal strengthening effects. By adjusting the high-aluminum, low-lithium glass-ceramics formula to control the ion exchange channels involved in aluminum crystallization from the glass phase to the microcrystalline phase, and by improving the ion exchange formula to utilize the large channels provided by aluminum oxide tetrahedrons, the ion exchange depth of the glass-ceramics can be greatly increased. By improving the glass-ceramics and ion exchange formulas, the stress relaxation and thermal fatigue problems caused by conventional secondary strengthening formulas can be effectively avoided. Furthermore, the improved glass-ceramics and ion exchange formulas increase the ion exchange quantity and exchange depth in this new glass-ceramics. Compared with conventional secondary strengthening methods, this method saves production costs and time. By controlling crystallization and improving the molten salt formula, the performance of the high-aluminum, low-lithium glass-ceramics is improved and the thermal fatigue and stress relaxation problems caused by conventional secondary strengthening molten salt-strengthened high-aluminum glass-ceramics are solved, making the product suitable for use in complex deep-sea environments.

[0060] In order to further illustrate the present invention, a pressure-resistant deep-sea transparent microcrystalline glass and a preparation method thereof provided by the present invention are described in detail below in combination with examples, but it should not be understood as limiting the scope of protection of the present invention.

[0061] Example

[0062] Ingredients: First determine the components of the sample formula (as shown in Table 1), calculate the specific amount of raw materials required according to the mass percentage of each component in Table 1, weigh the calculated raw materials using a precision electronic scale, and finally mix the raw materials evenly to obtain the batch material.

[0063] Melting and homogenization: put the evenly mixed batch materials into a corundum crucible, melt and homogenize them in a high-temperature electric furnace, with a heating rate of 3℃ / min, a melting temperature of 1650℃, and a holding time of 3h.

[0064] Molding: Pour the molten glass into a graphite mold and let it stand to form.

[0065] Annealing: Place the cooled and formed glass into a muffle furnace with a predetermined temperature for annealing, and keep it at about 600℃ for 2 hours. After cooling, take it out to obtain ordinary glass.

[0066] Heat Treatment: The cleaned and polished glass was placed in a box-type silicon carbon rod resistance furnace for a two-step heat treatment. The heating rate was set at 5°C / min. Nucleation: The nucleation temperature was 700°C and the holding time was 2 hours. Crystallization: The crystallization temperature was 850°C and the holding time was 2 hours. After cooling to room temperature, the glass-ceramics were removed and cleaned and dried.

[0067] Preheating: Place the glass-ceramics in a preheating furnace and set the temperature to 10°C / min, heat to 350°C and keep warm for 35 minutes.

[0068] Chemical strengthening 1: The preheated glass substrate and the ion sieve were added to a first molten salt at 450° C., one after the other. The composition of the first molten salt is shown in Table 2. The holding time was 3 h.

[0069] Preheating: Place the once strengthened glass-ceramics in a muffle furnace for heat treatment at a temperature of 500-530°C for 3 hours.

[0070] Chemical strengthening 2: The heat-treated microcrystalline glass was placed in a second molten salt at 400-500° C. for secondary strengthening. The first molten salt composition content is shown in Table 3. The heat-keeping time was 2 hours to obtain microcrystalline glass.

[0071] By comparing with high lithium and low aluminum glass-ceramics that have undergone a single ion exchange

[0072] Comparative Example 1

[0073] Glass-ceramics were prepared according to the preparation process in the embodiment, except that the glass-ceramics formula in Example 1 refers to Table 1, and only one chemical strengthening was performed. The composition of the molten salt used is shown in Table 2, and other process parameters are the same as in the embodiment.

[0074] Comparative Example 2

[0075] Glass-ceramics were prepared according to the preparation process in the embodiment, except that the glass-ceramics formula in Example 2 refers to Table 1, and only one chemical strengthening was performed. The molten salt composition used refers to Table 2, and other process parameters are the same as in the embodiment.

[0076] Table 1 Content of glass-ceramics in the examples (wt%)

[0077]

[0078]

[0079] Table 2 Composition content of the first molten salt in the embodiment (wt%)

[0080]

[0081] Table 3 Composition content of the second molten salt in the embodiment (wt%)

[0082]

[0083] The performance of the glass-ceramics prepared in Examples 1 to 7 was tested. The results are shown in Table 4.

[0084] The bulk glass-ceramics obtained in the embodiment of the present invention were subjected to performance testing according to the following method. The specific test items and test methods (or test standards) are as follows:

[0085] Elastic modulus test: The static method is used to test the stress-strain of the material in the elastic deformation range. The static method refers to applying a constant bending stress on the specimen, measuring its elastic bending deflection, and calculating the elastic modulus based on the stress and strain.

[0086] Visible light transmittance of glass: tested using a transmittance meter with a parallel light path design.

[0087] The depth of the chemically strengthened stress layer of glass and the surface compressive stress of glass are calculated using the SLP-2000 compressive stress tester, which uses the optical path difference and polarization characteristics caused by the delay of the laser beam on the polarized light path to calculate the surface compressive stress and the thickness of the compressive stress layer.

[0088] Drop ball impact value: It is the height required to drop a steel ball of a certain mass from different heights onto the surface of the material until it destroys the material.

[0089] Four-point bending test strength: Place the strip specimen flat in the bending test fixture to form a simply supported beam. The distance between the two lower support points of the specimen makes the specimen length adjustable. There are two symmetrical loading points above the specimen. The required strength is measured by applying force to the specimen until the material deforms.

[0090] Alkali resistance: tested according to the acid and alkali resistance test method in the standard "Low expansion transparent microcrystalline glass" JC / T2157-2012

[0091] Acid resistance: tested according to the acid and alkali resistance test method in the standard "Low Expansion Transparent Glass-Ceramics" JC / T2157-2012.

[0092] Vickers hardness: tested under the conditions of test load 200gf and dwell time 10s.

[0093] Table 4 Performance test of glass-ceramics in the examples

[0094]

[0095] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing pressure-resistant deep-sea transparent glass-ceramics, comprising the following steps: A) uniformly mixing the raw materials and melting and homogenizing them to obtain molten glass; The raw materials include the following components in mass fractions: B) pouring the glass liquid into a mold to form the mold, and then annealing the formed glass to obtain ordinary glass; C) subjecting ordinary glass to a nucleation heat treatment and a crystallization heat treatment in sequence to obtain glass-ceramics; D) preheating the glass-ceramics for the first time and placing it in a first molten salt for the first chemical strengthening; The first molten salt comprises 28-30 wt% of sodium nitrate, 59-61 wt% of potassium nitrate, 0.02-0.03 wt% of potassium silicate, 0.02-0.03 wt% of sodium silicate, 0.2-0.3 wt% of aluminum oxide, 9-12 wt% of copper chloride, and 0.01-0.1 wt% of cerium oxide; E) preheating the glass-ceramics after the first chemical strengthening for a second time, placing the glass-ceramics in a second molten salt, and performing a second chemical strengthening to obtain a compression-resistant deep-sea transparent glass-ceramics; The second molten salt includes 93-96 wt% of potassium nitrate, 0.3-0.6 wt% of potassium hydroxide, 0.02-0.03 wt% of potassium silicate, 2-5 wt% of diatomaceous earth, 0.02-0.03 wt% of lanthanum oxide, and 1.4-1.5 wt% of potassium carbonate.

2. The preparation method according to claim 1, characterized in that The temperature of the melt homogenization is 1580-1650° C., and the holding time of the melt homogenization is 3-4 hours.

3. The preparation method according to claim 1, characterized in that The annealing temperature is 600-750° C.; the annealing holding time is 1-2 hours.

4. The preparation method according to claim 1, characterized in that The temperature of the nucleation heat treatment is 680-720°C, and the holding time of the nucleation heat treatment is 2-4 hours; The temperature of the crystallization heat treatment is 780-850° C., and the holding time of the crystallization heat treatment is 2-4 hours.

5. The preparation method according to claim 1, characterized in that The temperature of the first preheating is 300-400° C.; the insulation time of the first preheating is 30-40 minutes.

6. The preparation method according to claim 5, characterized in that The temperature of the first chemical strengthening is 450-550° C., and the holding time of the first chemical strengthening is 1-5 hours.

7. The preparation method according to claim 6, characterized in that The temperature of the second preheating is 500-530° C.; the insulation time of the second preheating is 2-4 hours.

8. The preparation method according to claim 7, characterized in that The temperature of the second chemical strengthening is 400-500° C., and the holding time of the second chemical strengthening is 1-5 hours.

9. The preparation method according to any one of claims 1 to 8, characterized in that: Ion sieves were added during the first chemical strengthening process to absorb Li in the molten salt. + .

10. The pressure-resistant deep-sea transparent glass-ceramics prepared by the preparation method according to any one of claims 1 to 9.

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