阅读说明：本技术 钠铝硅酸盐纳米晶透明陶瓷、其制备方法及产品 (Sodium-aluminium silicate nanocrystalline transparent ceramic, preparation method and product thereof ) 是由 姚全星 罗恺 袁晓波 刘庆 李军旗 于 2020-04-29 设计创作，主要内容包括：一种钠铝硅酸盐纳米晶透明陶瓷,所述钠铝硅酸盐纳米晶透明陶瓷包括玻璃相和混合于所述玻璃相中的结晶相；所述钠铝硅酸盐纳米晶透明陶瓷包括以下质量分数的组分：40％-75％的二氧化硅、5％-35％的氧化铝、2％-20％的氧化钠、1％-10％的氧化钾、0.5％-10％的氧化钙以及1％-10％的五氧化二磷。本申请还提供一种所述钠铝硅酸盐纳米晶透明陶瓷的制备方法以及包括所述钠铝硅酸盐纳米晶透明陶瓷的产品。(A sodium aluminosilicate nanocrystalline transparent ceramic comprising a glass phase and a crystalline phase mixed in the glass phase; the sodium aluminosilicate nanocrystalline transparent ceramic comprises the following components in percentage by mass: 40 to 75 percent of silicon dioxide, 5 to 35 percent of aluminum oxide, 2 to 20 percent of sodium oxide, 1 to 10 percent of potassium oxide, 0.5 to 10 percent of calcium oxide and 1 to 10 percent of phosphorus pentoxide. The application also provides a preparation method of the sodium aluminosilicate nanocrystalline transparent ceramic and a product containing the sodium aluminosilicate nanocrystalline transparent ceramic.)

1. A sodium aluminosilicate nanocrystalline transparent ceramic, characterized in that the sodium aluminosilicate nanocrystalline transparent ceramic comprises a glass phase and a crystalline phase mixed in the glass phase; the sodium aluminosilicate nanocrystalline transparent ceramic comprises the following components in percentage by mass: 40 to 75 percent of silicon dioxide, 5 to 35 percent of aluminum oxide, 2 to 20 percent of sodium oxide, 1 to 10 percent of potassium oxide, 0.5 to 10 percent of calcium oxide and 1 to 10 percent of phosphorus pentoxide.

2. The soda-aluminosilicate nanocrystalline transparent ceramic according to claim 1, wherein the crystalline phase includes a primary crystalline phase selected from at least one of nepheline, kaliophilite, celsian, β -quartz, spinel, forsterite, and anatase; the mass of the main crystalline phase is greater than or equal to 90% of the total mass of the crystalline phases.

3. The soda-aluminosilicate nanocrystalline transparent ceramic according to claim 2, wherein each of the main crystal phases has a mass fraction greater than or equal to 5% in the main crystal phase.

4. The sodium aluminosilicate nanocrystalline transparent ceramic according to claim 3, wherein the primary crystalline phase comprises nepheline, the mass of the nepheline being greater than or equal to 50% of the total mass of the crystalline phases.

5. The sodium aluminosilicate nanocrystalline ceramic according to claim 1, further comprising magnesium oxide in a mass fraction of 0% to 10%, zinc oxide in a mass fraction of 0% to 10%, and lithium oxide in a mass fraction of 0% to 10%.

6. The sodium aluminosilicate nanocrystalline ceramic according to claim 1, further comprising 0-10% by mass of titanium dioxide and 0-8% by mass of zirconium oxide.

7. The sodium aluminosilicate nanocrystalline transparent ceramic according to claim 1, further comprising tin dioxide in a mass fraction of 0% to 5%, antimony oxide in a mass fraction of 0% to 5%, and arsenic trioxide in a mass fraction of 0% to 5%.

8. The sodium aluminosilicate nanocrystalline transparent ceramic according to claim 1, further comprising 0% -10% by mass of barium oxide, 0% -8% by mass of boron oxide, and 0% -8% by mass of ferric oxide.

9. A method for preparing the sodium aluminosilicate nanocrystalline transparent ceramic according to any one of claims 1 to 8, characterized by comprising the following steps:

mixing silicon dioxide, aluminum oxide, sodium oxide, potassium oxide, calcium oxide and phosphorus pentoxide in proportion, and then carrying out melting treatment to obtain a melt;

molding the melt to obtain a semi-finished product; and

and carrying out heat treatment on the semi-finished product to precipitate a crystalline phase, thereby obtaining the sodium aluminosilicate nanocrystalline transparent ceramic.

10. The method for preparing the sodium aluminosilicate nanocrystalline transparent ceramic according to claim 9, wherein the heat treatment includes a first stage heat treatment at a temperature of 600 ℃ to 950 ℃ for a time of 0.5h to 12h, and a second stage heat treatment at a temperature of 700 ℃ to 1250 ℃ for a time of 0.5h to 12 h.

11. A product comprising the sodium aluminosilicate nanocrystalline transparent ceramic according to any one of claims 1 to 8.

Technical Field

The application relates to the field of chemical industry, in particular to a sodium aluminosilicate nanocrystalline transparent ceramic, a preparation method thereof and a product.

Background

Currently, with the rapid development of high and new technologies such as 5G communication, wireless charging and flexible OLED curved screens, people have higher requirements on the appearance and performance of 3C intelligent products such as mobile phones and tablet computers. In the aspect of material application, the traditional metal material can cause shielding or interference effect on signal transmission; the plastic material has poor characteristics, and the requirements of people on the appearance of middle and high-end mobile phones are difficult to meet, so that the inorganic non-metal transparent material becomes the mainstream material of the display cover plate, such as glass and ceramic. The ceramic is high in manufacturing cost and difficult to process, and the aluminosilicate glass cover plate is widely applied at present, but common glass is fragile and cannot resist falling.

Disclosure of Invention

In view of the above, it is necessary to provide a sodium aluminosilicate nanocrystalline transparent ceramic with high strength, high hardness and strong impact resistance to solve the above problems.

In addition, a preparation method of the sodium aluminosilicate nanocrystalline transparent ceramic is also needed to be provided.

In addition, a product is also needed.

A sodium aluminosilicate nanocrystalline transparent ceramic comprising a glass phase and a crystalline phase mixed in the glass phase; the sodium aluminosilicate nanocrystalline transparent ceramic comprises the following components in percentage by mass: 40 to 75 percent of silicon dioxide, 5 to 35 percent of aluminum oxide, 2 to 20 percent of sodium oxide, 1 to 10 percent of potassium oxide, 0.5 to 10 percent of calcium oxide and 1 to 10 percent of phosphorus pentoxide.

In an embodiment of the present application, the crystalline phase includes a primary crystalline phase selected from at least one of nepheline, kaliophilite, celsian, beta-quartz, spinel, forsterite, and anatase; the mass of the main crystalline phase is greater than or equal to 90% of the total mass of the crystalline phases.

In an embodiment of the present application, the mass fraction of each of the main crystal phases in the main crystal phase is greater than or equal to 5%.

In an embodiment of the present application, the primary crystalline phase comprises nepheline, the mass of which is greater than or equal to 50% of the total mass of the crystalline phases.

In one embodiment of the present application, the sodium aluminosilicate nanocrystalline transparent ceramic further comprises magnesium oxide in a mass fraction of 0% to 10%, zinc oxide in a mass fraction of 0% to 10%, and lithium oxide in a mass fraction of 0% to 10%.

In one embodiment of the present application, the sodium aluminosilicate nanocrystalline transparent ceramic further comprises 0% to 10% by mass of titanium dioxide and 0% to 8% by mass of zirconium oxide.

In an embodiment of the present application, the sodium aluminosilicate nanocrystalline transparent ceramic further includes 0% to 5% of tin dioxide, 0% to 5% of antimony oxide, and 0% to 5% of arsenic trioxide by mass fraction.

In an embodiment of the present application, the sodium aluminosilicate nanocrystalline transparent ceramic further includes, by mass, 0% to 10% of barium oxide, 0% to 8% of boron oxide, and 0% to 8% of ferric oxide.

A preparation method of the sodium aluminosilicate nanocrystalline transparent ceramic comprises the following steps:

mixing silicon dioxide, aluminum oxide, sodium oxide, potassium oxide, calcium oxide and phosphorus pentoxide in proportion, and then carrying out melting treatment to obtain a melt;

molding the melt to obtain a semi-finished product; and

and carrying out heat treatment on the semi-finished product to precipitate a crystalline phase, thereby obtaining the sodium aluminosilicate nanocrystalline transparent ceramic.

In an embodiment of the present application, the heat treatment includes a first stage heat treatment at a temperature of 600 ℃ to 950 ℃, for a time of 0.5h to 12h, and a second stage heat treatment at a temperature of 700 ℃ to 1250 ℃, for a time of 0.5h to 12 h.

A product comprising the sodium aluminosilicate nanocrystalline transparent ceramic.

The sodium aluminosilicate nanocrystalline transparent ceramic provided by the application comprises a crystalline phase, wherein the crystalline phase is beneficial to preventing cracks or microcracks from expanding in the sodium aluminosilicate nanocrystalline transparent ceramic, and the strength and fracture toughness of the sodium aluminosilicate nanocrystalline transparent ceramic are improved; in addition, by designing different crystalline phases, the advantages of the respective crystalline phases are exerted, so that the performance of the sodium aluminosilicate nanocrystalline transparent ceramic is improved; the mechanical strength, the surface hardness, the wear resistance, the impact resistance and other properties of the sodium aluminosilicate nanocrystalline transparent ceramic are improved through the proportion of different components.

Detailed Description

In order that the above objects, features and advantages of the present application may be more clearly understood, the following detailed description of the present application describes the present application in detail. In addition, the embodiments and features of the embodiments of the present application may be combined with each other without conflict. In the following description, numerous specific details are set forth to provide a thorough understanding of the present application, and the described embodiments are merely a subset of the embodiments of the present application, rather than all embodiments. All other embodiments obtained by a person of ordinary skill in the art without any inventive work based on the embodiments in the present application are within the scope of protection of the present application.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and/or" includes all and any combination of one or more of the associated listed items.

Embodiments of the present disclosure provide a sodium aluminosilicate nanocrystalline transparent ceramic, which includes a glass phase and a crystalline phase, and the glass phase is crystallized and a crystalline phase is grown in the glass phase, thereby forming a composite material having a glass phase and a crystalline phase. Wherein the crystalline phase is fine and uniformly distributed in the glass phase, so that the sodium aluminosilicate nanocrystalline transparent ceramic has excellent performance.

The grain size in the crystalline phase is less than or equal to 100 nm.

Preferably, the grain size in the crystalline phase is less than or equal to 20 nm.

The crystalline phase comprises a main crystalline phase having a mass greater than or equal to 90% of the total mass of the crystalline phases. Wherein the main crystal phase may be selected from at least one of nepheline, kaliophilite, celsian, beta-quartz, spinel, forsterite, and anatase, i.e., the main crystal phase may be composed of one or more kinds of crystals.

The crystalline phase further includes a secondary crystalline phase, which may be selected from at least one of nepheline, kalsilite, celsian, beta-quartz, spinel, forsterite, and anatase, and which is different from the primary crystalline phase in the same soda-aluminosilicate nanocrystalline transparent ceramic. Wherein the mass of each of the secondary crystalline phases is less than 5% of the total mass of the crystalline phases, i.e. the mass of each of the primary crystalline phases is greater than or equal to 5% of the total mass of the crystalline phases.

Preferably, nepheline is included in the primary crystalline phase, i.e., the primary crystalline phase can be nepheline, nepheline and celsian, nepheline and beta-quartz, nepheline and spinel. The mass of the nepheline is greater than or equal to 50% of the total mass of the crystalline phase and the mass of the nepheline is greater than or equal to 45% of the total mass of the main crystalline phase.

Wherein the chemical formula of the nepheline crystal is NaAlSiO₄The nepheline belongs to a hexagonal crystal system framework structure, and the sodium aluminosilicate nanocrystalline transparent ceramic taking the nepheline as a main crystal phase has the advantages of high strength and excellent fracture toughness; in addition, the nepheline contains sodium elements, the nepheline can be subjected to ion exchange in a molten salt such as potassium nitrate or sodium nitrate to form kaliophilite, and the kaliophilite grows at the periphery of the nepheline to form an extrusion effect, so that the effect of mutual enhancement among different crystals is achieved. In one embodiment of the present application, the sodium aluminosilicate nanocrystalline transparent ceramic has nepheline as the primary crystal phase and kaliophilite as the secondary crystal phase, the kaliumNepheline is grown at the nepheline peripheral boundary.

The sodium aluminosilicate nanocrystalline transparent ceramic takes nepheline and celsian as main crystal phases, wherein the nepheline has the advantages of high strength and excellent fracture toughness, the celsian has lower thermal expansion coefficient, and the celsian and the nepheline form the mutual enhancement effect, so that the sodium aluminosilicate nanocrystalline transparent ceramic has lower thermal expansion coefficient while having high strength and excellent fracture toughness.

The beta-quartz and the nepheline are combined to mutually form an enhancement effect, and the transmittance of the sodium aluminosilicate nanocrystalline transparent ceramic can be improved and the thermal expansion coefficient of the sodium aluminosilicate nanocrystalline transparent ceramic can be reduced.

The sodium aluminosilicate nanocrystalline transparent ceramic taking nepheline and spinel as main crystal phases is characterized in that the spinel has high mechanical strength, high surface hardness and good impact resistance, and the nepheline and the spinel are combined to mutually form an enhancement effect, so that the mechanical strength, the surface hardness and the impact resistance of the sodium aluminosilicate nanocrystalline transparent ceramic can be improved.

The existence of the crystalline phase, on one hand, hinders the expansion of cracks or microcracks generated in the sodium aluminosilicate nanocrystalline transparent ceramic, improves the strength of the sodium aluminosilicate nanocrystalline transparent ceramic, and improves the fracture toughness of the sodium aluminosilicate nanocrystalline transparent ceramic; on the other hand, different crystal phases have different excellent performances, and the combination of a plurality of crystal phases ensures that the sodium aluminosilicate nanocrystalline transparent ceramic also has different excellent characteristics due to different types and contents of the crystal phases, and has excellent mechanical strength, surface hardness, thermal expansion performance, chemical corrosion resistance, wear resistance, impact resistance, thermal stability and the like. The sodium-aluminum-silicon nanocrystalline transparent ceramic has outstanding advantages in properties such as high strength, high hardness, high impact resistance and heat resistance stability.

The sodium aluminosilicate nanocrystalline transparent ceramic comprises the following components in percentage by mass: 40% -75% of silicon dioxide (SiO)₂) 5% -35% of alumina (Al)₂O₃) 2% -20% of sodium oxide (Na)₂O), 1% -10% of potassium oxide (K)₂O), 0.5-10% of calcium oxide (CaO) and 1-10% of phosphorus pentoxide (P)₂O₅)。

The SiO₂SiO, a basic skeleton for forming the sodium aluminosilicate nanocrystalline transparent ceramic₂An excessively low content may destabilize or coarsen the crystal phase generated in the sodium aluminosilicate nanocrystalline transparent ceramic and may cause the sodium aluminosilicate nanocrystalline transparent ceramic to lack gloss or even to be devitrified, while SiO₂Too high a content makes the raw material difficult to melt, so that the preparation process of the sodium aluminosilicate nanocrystalline transparent ceramic requires a higher melting temperature, and therefore, SiO₂The mass fraction of (A) should be controlled between 40% and 75%.

The Al is₂O₃Is used for increasing the mechanical strength and stability of the sodium aluminosilicate nanocrystalline transparent ceramic. However, when Al is used₂O₃When the content is too high, difficulty may occur in the melting process of the sodium aluminosilicate nanocrystalline transparent ceramic or the transmittance thereof may be reduced, and therefore, Al₂O₃The mass fraction of (A) should be controlled between 5% and 35%.

The Na is₂The O is used as an oxide outside the sodium aluminosilicate nanocrystalline transparent ceramic structure network, and can effectively reduce the viscosity of the sodium aluminosilicate nanocrystalline transparent ceramic so as to reduce the melting temperature. However, excessive Na₂The thermal expansion coefficient of the sodium aluminosilicate nanocrystalline transparent ceramic is increased by O, and the mechanical strength and the chemical stability of the sodium aluminosilicate nanocrystalline transparent ceramic are reduced; thus, Na₂The mass fraction of O is controlled between 2 percent and 20 percent.

Said K₂O acts like Na₂And O, as an oxide outside the structural network of the sodium aluminosilicate nanocrystalline transparent ceramic, can further effectively reduce the viscosity of the sodium aluminosilicate nanocrystalline transparent ceramic so as to reduce the melting temperature.

The CaO is used as a fluxing agent, so that the melting temperature of the raw materials and the viscosity of the molten liquid can be effectively reduced in the process of preparing the sodium aluminosilicate nanocrystalline transparent ceramic.

The P is₂O₅As a nucleating agent, the crystal is beneficial to promoting the precipitation of the crystal and stably existing after the crystal is precipitated.

Further, the sodium aluminosilicate nanocrystalline transparent ceramic also comprises 0-10% of magnesium oxide (MgO) and 0-10% of zinc oxide (ZnO) in mass fraction, wherein the MgO and the ZnO are used for enabling the sodium aluminosilicate nanocrystalline transparent ceramic to form a high-strength stable crystalline phase, and the MgO and the ZnO can also enhance the mechanical strength and the chemical stability of the nanocrystalline glass ceramic.

Further, the sodium aluminosilicate nanocrystalline transparent ceramic also comprises lithium oxide (Li) with the mass fraction of 0-10%₂O), the Li₂And O is used for adjusting the structure and the performance of the sodium aluminosilicate nanocrystalline transparent ceramic.

Further, the sodium aluminosilicate nanocrystalline transparent ceramic also comprises 0-10% of barium oxide (BaO) and 0-10% of boron oxide (B) in percentage by mass₂O₃) And 0% -8% of ferric oxide (Fe)₂O₃). The BaO and B₂O₃And Fe₂O₃As a flux, the temperature at which the raw material is melted and the viscosity of the melt can be effectively reduced. Wherein, the Fe₂O₃Can also be used as a nucleating agent, is beneficial to promoting the precipitation of crystals and the stable existence of excessive Fe after the precipitation of the crystals₂O₃(greater than 8%) affects the transparency of the sodium aluminosilicate nanocrystalline transparent ceramic, so Fe₂O₃The mass fraction of (A) is controlled to be 0-8%.

Further, the sodium aluminosilicate nanocrystalline transparent ceramic also comprises 0-10% of titanium dioxide (TiO)₂) And 0% -8% of zirconium oxide (ZrO)₂) Said TiO being₂And the ZrO₂As a nucleating agent, the crystal is beneficial to promoting the precipitation of the crystal and stably existing after the crystal is precipitated.

Further, the sodium aluminosilicate nanocrystalline transparent ceramic also comprises 0-5% of sodium aluminosilicate nanocrystalline by mass fractionTin dioxide (SnO)₂) 0% -5% of antimony oxide (Sb)₂O₃) 0% -5% of arsenic trioxide (As)₂O₃). The SnO₂、Sb₂O₃And As₂O₃As a clarifying agent, the sodium aluminosilicate nanocrystalline transparent ceramic is beneficial to promoting clarification and homogenization of the melted raw materials in the preparation process of the sodium aluminosilicate nanocrystalline transparent ceramic and improving the compactness of the sodium aluminosilicate nanocrystalline transparent ceramic.

Further, fluorine-containing compounds may also be used as clarifying agents, such as calcium fluoride (CaF)₂)。

The transmittance of the sodium aluminosilicate nanocrystalline transparent ceramic is greater than or equal to 90% in the visible light range of 400nm-760 nm.

The linear thermal expansion coefficient of the sodium aluminosilicate nanocrystalline transparent ceramic is 50 x 10^-7/ ℃-120*10^-7The temperature is higher than the temperature, and the thermal expansion coefficient can be adjusted according to the components and the proportion in the sodium aluminosilicate nanocrystalline transparent ceramic.

The density of the sodium aluminosilicate nanocrystalline transparent ceramic is 2.3g/cm³-2.6g/cm³。

The sodium aluminosilicate nanocrystalline transparent ceramic can be subjected to surface grinding and polishing treatment, and the minimum surface roughness of the sodium aluminosilicate nanocrystalline transparent ceramic can be less than or equal to 1 nm.

The sodium aluminosilicate nanocrystalline transparent ceramic can be subjected to strengthening treatment, and the strengthened surface Compressive Stress (CS) is 300MPa-1200 MPa. The prepared sodium aluminosilicate nanocrystalline transparent ceramic has good chemical enhancement effect, wherein the nepheline crystal can be subjected to ion exchange to form a compressive stress layer on the surface of the crystal, the thickness (DOL) of the compressive stress layer is 40-150 μm, the bending strength after enhancement is greater than or equal to 1000MPa, and the impact strength is greater than or equal to 2.5J, and compared with the impact strength of the common aluminosilicate glass after enhancement, the impact strength is about doubled.

The Vickers hardness of the sodium aluminosilicate nanocrystalline transparent ceramic before strengthening is greater than or equal to 650kgf/mm²The Vickers hardness of the strengthened sodium aluminosilicate nanocrystalline transparent ceramic is greater than or equal to 870kgf/mm²。

The sodium aluminosilicate nanocrystalline transparent ceramic can be further formed into a multi-curved surface or 3D curved surface structure through reheating. The sodium aluminosilicate nanocrystalline transparent ceramic can also be processed into shapes of different products, such as screen cover plates, watch covers, dials, lenses and the like.

The application also provides a preparation method of the sodium aluminosilicate nanocrystalline transparent ceramic, which comprises the following steps:

step S1: mixing the raw materials in proportion, placing the mixture into a reaction kettle, and melting the mixed raw materials to obtain a melt.

Wherein the raw materials are all oxides, and the purity of the raw materials is greater than or equal to 99.5%. The raw material at least comprises SiO₂、Al₂O₃、Na₂O、K₂O, CaO and P₂O₅。

Specifically, the raw materials are weighed according to a certain proportion and then mixed in a mixer; and putting the mixed raw materials into a smelting furnace, and heating to 1200-1800 ℃ to melt the raw materials to obtain the melt.

Preferably, the mixed raw materials are heated to 1400-1600 ℃ to melt the raw materials, and then heated to 1500-1700 ℃ and kept for 2-10 h to clarify and homogenize the melted raw materials. Wherein the clarification is to remove gas and impurities generated during heating and the homogenization is to eliminate inhomogeneities in the molten raw material.

Step S2: and forming the melt to obtain a semi-finished product.

There are various molding methods, such as injecting the molten material into a mold through a runner to cool and mold, supplying the molten material to a molding machine to press and mold, flowing the molten material out of a chute onto a flat table, rolling the molten material into a flat plate material by a heat-resistant roll, or drawing the molten material along a refractory plate into a flat plate material. The above is merely illustrative and not restrictive, and those skilled in the art can adjust the shape of the product as required, the product includes but is not limited to vessel, cup, kitchen ware, etc., the shape includes but is not limited to rectangular parallelepiped and cylinder, etc.

During the forming process, the cooling process of the melt needs to be controlled well, so that the difference of the structure and the performance caused by uneven heating during cooling is prevented.

Step S3: and carrying out heat treatment on the semi-finished product to precipitate a crystalline phase.

Specifically, the semi-finished product is placed in a crystallization furnace, the temperature is controlled to be 600-950 ℃, the temperature is kept for 0.5-12 h, the first-stage heat treatment is carried out, and crystals are separated out in the process. Then controlling the temperature at 700-1250 ℃, and preserving heat for 0.5-12 h to carry out second-stage heat treatment, wherein the precipitated crystals grow in the process. And finally, cooling to normal temperature to obtain the sodium aluminosilicate nanocrystalline transparent ceramic. In the heat treatment process, the temperature, time and heating rate of crystals need to be strictly controlled in the precipitation and growth processes, and the temperature and time required by different crystal forms have certain difference.

In one embodiment of the present application, the temperature of the first stage heat treatment is 600 ℃ to 850 ℃, the time of the first stage heat treatment is 0.5h to 10h, the temperature of the second stage heat treatment is 700 ℃ to 1000 ℃, and the time of the second stage heat treatment is 0.5h to 10 h. In this embodiment, the sodium aluminosilicate nanocrystalline transparent ceramic produced has a primary crystalline phase of nepheline, i.e., the mass of nepheline is greater than or equal to 90% of the total mass of the crystalline phases; the crystalline phase also has minor crystalline phases of kaliophilite, celsian, beta-quartz, spinel, forsterite and anatase, all of which have a mass less than 5% of the total mass of the crystalline phases.

In one embodiment of the present application, the temperature of the first stage heat treatment is 650 ℃ to 850 ℃, the time of the first stage heat treatment is 0.5h to 10h, the temperature of the second stage heat treatment is 750 ℃ to 950 ℃, and the time of the second stage heat treatment is 0.5h to 8 h. In the embodiment, the main crystal phase of the sodium aluminosilicate nanocrystalline transparent ceramic is nepheline and celsian, namely the total mass of the nepheline and the celsian is more than or equal to 90 percent of the total mass of the crystal phase, wherein the mass ratio of the nepheline to the celsian is 1:1-15: 1; the crystalline phase also has minor crystalline phases of kaliophilite, beta-quartz, spinel, forsterite and anatase, all of which have a mass less than 5% of the total mass of the crystalline phases.

In one embodiment of the present application, the temperature of the first stage heat treatment is 600 ℃ to 800 ℃, the time of the first stage heat treatment is 0.5h to 10h, the temperature of the second stage heat treatment is 750 ℃ to 980 ℃, and the time of the second stage heat treatment is 0.5h to 8 h. In this embodiment, the sodium aluminosilicate nanocrystalline transparent ceramic produced has a main crystal phase of nepheline and beta-quartz, i.e., the total mass of nepheline and beta-quartz is greater than or equal to 90% of the total mass of the crystal phase, wherein the mass ratio of nepheline to beta-quartz is 1:1 to 15: 1; the crystal phase also has minor crystal phases such as kaliophilite, celsian, spinel, forsterite and anatase, and the mass of the crystals such as kaliophilite, celsian, spinel, forsterite and anatase is less than 5% of the total mass of the crystal phases.

In one embodiment of the present application, the temperature of the first stage heat treatment is 650 ℃ to 850 ℃, the time of the first stage heat treatment is 1h to 10h, the temperature of the second stage heat treatment is 750 ℃ to 950 ℃, and the time of the second stage heat treatment is 1h to 8 h. In the present embodiment, the main crystal phase of the sodium aluminosilicate nanocrystalline transparent ceramic prepared is nepheline and spinel, i.e. the total mass of the nepheline and the spinel is greater than or equal to 90% of the total mass of the crystal phase, wherein the mass ratio of the nepheline to the spinel is 1:1-15: 1; the crystalline phase also has minor crystalline phases such as kaliophilite, celsian, beta-quartz, forsterite and anatase, and the mass of the kaliophilite, celsian, beta-quartz, forsterite and anatase is less than 5% of the total mass of the crystalline phases.

Please refer to table 1, which shows the heat treatment conditions and the types of the main crystal phases of the prepared sodium aluminosilicate nanocrystalline transparent ceramics.

TABLE 1

Further, the preparation method also comprises the post-treatment steps of cutting, surface treatment, strengthening and the like of the sodium aluminosilicate nanocrystalline transparent ceramic.

And cutting the sodium aluminosilicate nanocrystalline transparent ceramic to obtain a product with a certain shape, and then carrying out surface treatment steps such as grinding, polishing and the like to remove impurities and defects on the surface of the sodium aluminosilicate nanocrystalline transparent ceramic.

Further, the performance of the sodium aluminosilicate nanocrystalline transparent ceramic is enhanced through a strengthening treatment step. In one embodiment, the sodium aluminosilicate nanocrystalline transparent ceramic is ion exchanged in a molten salt that includes a potassium salt (e.g., potassium nitrate) or a sodium salt (e.g., sodium nitrate) to form a compressive stress layer on the surface of the sodium aluminosilicate nanocrystalline transparent ceramic to achieve an enhancement effect, e.g., some nephelines are ion exchanged in a potassium nitrate molten salt to form kaliophilite, which grows around the nepheline to achieve the enhancement effect. In another embodiment, the sodium aluminosilicate nanocrystalline transparent ceramic may also be coated to enhance its performance.

The present application also provides a product comprising the sodium aluminosilicate nanocrystalline transparent ceramic, for example, the sodium aluminosilicate nanocrystalline transparent ceramic may be made into a back shell of the product. The product may be a consumer electronic product (such as a mobile communication device, a tablet computer, a notebook computer, etc.), an electric tool, an unmanned aerial vehicle, an energy storage device, a power device, an optical lens, etc., or may be a mechanical disk, an instrument panel, a dental material, a kitchen ware, an equipment, etc., which are merely exemplified above, but not limited thereto.

The present application is described below with reference to specific examples.