Layered composite structure of multi-scale ceramic fiber reinforced synthetic jadeite and low-temperature sintering method thereof

Abstract

The invention belongs to the field of synthetic jadeite, and particularly relates to a layered composite structure of multi-scale ceramic fiber reinforced synthetic jadeite and a preparation method thereof, and the composite structure is composed of a jadeite matrix material, a ceramic fiber reinforced material and a color developing agent. The preparation method comprises the following steps: mixing the jadeite base material and the color developing agent, and then carrying out ball milling to obtain the jadeite base material coated with the color developing agent; mixing the ceramic fiber reinforced material with a silane coupling agent to obtain a modified ceramic fiber reinforced material; mixing the color developing agent coated jadeite base material, the modified ceramic fiber reinforced material and a dispersing agent, and treating in an electric field and an ultrasonic field to obtain prefabricated slurry; and finally, filling a synthetic jadeite mold with the prefabricated slurry, and carrying out gradient heating firing to obtain the layered composite structure of the multi-scale ceramic fiber reinforced synthetic jadeite. Different ceramic fiber reinforced materials are compounded for use, electric field-ultrasonic field superposition treatment is combined, and low-temperature sintering is performed, so that the multi-scale ceramic fiber reinforced synthetic jadeite can be obtained.

Description

Technical Field

[0001] The present invention belongs to the field of synthetic jadeite, and specifically relates to a layered composite structure of multi-scale ceramic fiber reinforced synthetic jadeite and its low-temperature sintering method. Background Art

[0002] As the "king of jade", the natural formation of jadeite requires hundreds of millions of years of high-temperature and high-pressure geological processes, resulting in the increasing scarcity of high-quality natural jadeite resources and sky-high market prices. To meet the market demand, artificial synthetic jadeite technology has received wide attention since the 1960s. However, there are still some problems with the existing synthetic jadeite. For example, traditional synthetic jadeite mainly uses a single matrix material (such as a mixture of jadeite microcrystals and glass phase), with a flexural strength lower than 200 MPa and a fracture toughness ≤ 2.5 MPa·m （¹ / ²） , which is difficult to meet the mechanical requirements for jewelry carving and long-term wearing.

[0003] At the same time, the existing synthetic jadeite often uses high-temperature and high-pressure methods or sol-gel methods for preparation. Among them, the high-temperature and high-pressure method requires the use of a six-sided top press to prepare synthetic jadeite under the condition of 6.0 GPa, and its loss rate for equipment is very high, and the single-piece production cost far exceeds that of natural jadeite. Although the sol-gel method reduces the temperature requirements, the synthetic jadeite is prone to incomplete crystallization, resulting in a loose texture, reducing its fracture toughness and flexural properties. It can be seen that there are also certain defects in the existing preparation methods of synthetic jadeite.

[0004] Based on this, there is an urgent need in this field for a synthetic jadeite with high anti-bending strength that can be further processed and worn for a long time and its corresponding preparation method. Summary of the Invention

[0005] In view of the above deficiencies of the prior art, the present invention provides a layered composite structure of multi-scale ceramic fiber reinforced synthetic jadeite and its preparation method, which can solve the problems of low anti-bending strength of existing synthetic jadeite and high cost of existing synthetic jadeite preparation methods.

[0006] To achieve the first objective, the present invention adopts the following technical solutions: The present invention provides a layered composite structure of multi-scale ceramic fiber reinforced synthetic jadeite and its low-temperature sintering method, which is characterized by including the following components by weight: Jadeite matrix material 75 - 125 parts Ceramic fiber reinforcing material 10 - 35 parts Color developer 1 - 5 parts.

[0007] Optionally, the jadeite matrix material includes the following components by weight: Aluminum oxide 50 - 70 parts Silicon dioxide 25 - 45 parts Mineralizer: 1 - 3 parts; Optionally, the particle sizes of aluminum oxide and silicon dioxide are independently 0.1 - 5 μm.

[0008] Optionally, the ceramic fiber reinforcing material includes chopped ceramic fibers and continuous ceramic fibers.

[0009] Optionally, the length of the continuous ceramic fibers is 1.5 - 10 mm; Optionally, the particle size of the continuous ceramic fibers is 0.5 - 30 μm; Optionally, the aspect ratio of the continuous ceramic fibers ≥ 50; Optionally, the mass ratio of the chopped ceramic fibers to the continuous ceramic fibers is (1: 0.5 - 3).

[0010] Optionally, the color developer includes one or more of chromium sesquioxide, iron sesquioxide, titanium dioxide, manganese dioxide, cobalt ferrite, magnesium oxide, neodymium oxide, and vanadium oxide.

[0011] Optionally, the particle size of the color developer is 0.01 - 0.5 μm.

[0012] Optionally, the mineralizer is one or more of lanthanum oxide, cerium oxide, neodymium oxide, yttrium oxide, europium oxide, and dysprosium oxide.

[0013] The second object of the present invention is to provide a preparation method for a layered composite structure of multi - scale ceramic fiber - reinforced synthetic jadeite, comprising the following steps: Mix the jadeite matrix material with the color developer and then ball - mill to obtain a jadeite matrix material coated with the color developer; Mix the ceramic fiber reinforcing material with a silane coupling agent to obtain a modified ceramic fiber reinforcing material; Mix the jadeite matrix material coated with the color developer, the modified ceramic fiber reinforcing material with a dispersant, and then obtain a pre - formed slurry under the treatment of an electric field and an ultrasonic field; Fill the pre - formed slurry into a synthetic jadeite mold and perform gradient temperature firing to obtain a layered composite structure of multi - scale ceramic fiber - reinforced synthetic jadeite.

[0014] Optionally, the ball - mill rotation speed is 300 - 500 rpm, the ball - mill time is 120 - 240 min, the grinding balls are zirconia grinding balls, and the diameter of the grinding balls is 3 - 10 mm.

[0015] Optionally, the dispersant is any one of an aqueous solution of sodium silicate, an aqueous solution of sodium hexametaphosphate, an aqueous solution of sodium citrate, and an aqueous solution of sodium ethylenediaminetetraacetate; Optionally, the pH of the dispersant is 8 - 11; The conductivity of the dispersant is 50 - 100 μS / cm.

[0016] Optionally, the electric field strength is 5 to 20 V / cm; Optionally, the action time of the electric field is 10 to 30 min; Optionally, the electric field energy consumption is 0.8 to 1.5 kWh / m³; Optionally, the frequency of the ultrasonic field is 30 to 50 kHz; Optionally, the power density of the ultrasonic field is 50 to 200 W / L.

[0017] Optionally, the gradient temperature rise firing includes the following steps: The prefabricated slurry is heated from room temperature to 500 to 700 °C at a heating rate of 3 to 8 °C / min and kept warm for 60 to 120 min, and then heated to 800 to 950 °C at a heating rate of 0.2 to 0.8 °C / min and kept warm for 180 to 360 min.

[0018] Advantages of the present invention: (1) Through the electric field-ultrasonic synergistic dispersion technology, the multi-scale ceramic fibers form a three-dimensional layered structure with gradient distribution and directional arrangement in the matrix: (2) The flexural strength of the ceramic fiber-reinforced synthetic jade prepared by the present invention reaches 390 to 430 MPa, far exceeding 200 to 220 MPa of the traditional synthetic jade. At the same time, the fracture toughness can also reach 4.0 to 4.2 MPa·m(¹ / ²), which is more than 60% higher than that of the prior art; (3) Using rare earth oxides as mineralizers can significantly reduce the sintering temperature and energy consumption; (4) The decomposition products of the silane coupling agent used in the present invention are pollution-free and meet the green manufacturing standards. Description of the drawings

[0019] Figure 1 It is a flowchart of the preparation method of the layered composite structure of multi-scale ceramic fiber-reinforced synthetic jade provided by the present invention. Detailed implementation manners

[0020] To make the purpose, technical solutions and effects of the present invention clearer and more definite, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0021] As used herein, the terms "comprising", "including", "having", "containing" or any other variation thereof are intended to cover non-exclusive inclusion. For example, a composition, step, method, article or device containing the listed elements is not necessarily limited to those elements, but may also include other elements not explicitly listed or elements inherent to such composition, step, method, article or device.

[0022] "Optional" or "any one" means that the matters or events described thereafter may or may not occur, and such description includes the cases where the events occur and the cases where the events do not occur.

[0023] The indefinite articles "a" and "an" before the elements or components of the present invention do not limit the quantity requirements (i.e., the number of occurrences) of the elements or components. Therefore, "a" or "an" should be interpreted as including one or at least one, and the singular forms of the elements or components also include the plural forms, unless the quantity clearly refers only to the singular form.

[0024] The descriptions of terms such as "one embodiment", "some embodiments", "exemplarily", "specific examples", or "some examples" described in the present invention mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this article, the schematic expressions of the above terms are not necessarily directed to the same embodiment or example.

[0025] The numerical ranges of the present invention not only include the point values listed in the embodiments, but also include any point values between the numerical ranges of the present invention that are not listed. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the range.

[0026] In the following embodiments, unless otherwise specified, all reagents and consumables are purchased from conventional reagent manufacturers in the art.

[0027] Based on this, this embodiment provides a layered composite structure of multi-scale ceramic fiber reinforced synthetic jadeite, which includes the following components by weight: Jadeite matrix material 75 - 125 parts Ceramic fiber reinforcing material 10 - 35 parts Color developer 1 - 5 parts.

[0028] In some specific embodiments, by way of example, the jadeite matrix material in the layered composite structure of multi-scale ceramic fiber reinforced synthetic jadeite can be 75 parts, 80 parts, 85 parts, 90 parts, 95 parts, 100 parts, 105 parts, 110 parts, 115 parts, 120 parts, 125 parts by weight, as long as the jadeite matrix material in the layered composite structure of multi-scale ceramic fiber reinforced synthetic jadeite meets the weight parts within this range.

[0029] In some specific embodiments, by way of example, the ceramic fiber reinforcing material in the layered composite structure of multi-scale ceramic fiber reinforced synthetic jadeite can be 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts by weight, as long as the weight parts of the ceramic fiber reinforcing material in the layered composite structure of multi-scale ceramic fiber reinforced synthetic jadeite meet the weight parts within this range.

[0030] In some specific embodiments, by way of example, in the layered composite structure of multi-scale ceramic fiber reinforced synthetic jadeite, the colorant can be 1 part, 2 parts, 3 parts, 4 parts, or 5 parts by weight.

[0031] In some specific embodiments, by way of example, the jadeite matrix material in the layered composite structure of multi-scale ceramic fiber reinforced synthetic jadeite includes the following components by weight: Aluminum oxide 50 - 70 parts Silicon dioxide 25 - 45 parts Mineralizer 1 - 3 parts.

[0032] In some specific embodiments, the aluminum oxide in the jadeite matrix material in the layered composite structure of multi-scale ceramic fiber reinforced synthetic jadeite can be 50 parts, 55 parts, 60 parts, 65 parts, or 70 parts by weight, as long as the weight fraction of aluminum oxide in the jadeite matrix material in the layered composite structure of multi-scale ceramic fiber reinforced synthetic jadeite is within this range.

[0033] In some specific embodiments, the silicon dioxide in the jadeite matrix material in the layered composite structure of multi-scale ceramic fiber reinforced synthetic jadeite can be 25, 30, 35, 40, or 45 by weight, as long as the weight fraction of silicon dioxide in the jadeite matrix material in the layered composite structure of multi-scale ceramic fiber reinforced synthetic jadeite is within this range.

[0034] In some specific embodiments, the mineralizer is one or more of lanthanum oxide, cerium oxide, neodymium oxide, yttrium oxide, europium oxide, and dysprosium oxide. Among them, lanthanum oxide and cerium oxide have high catalytic activity, which can promote the solid-phase reaction of the jadeite matrix material at low temperature and significantly reduce the firing temperature. Traditional synthetic jadeite requires a high temperature above 1300 °C, while after adding rare earth oxides, the firing temperature can be reduced to 800 - 950 °C, achieving low-temperature firing and saving energy consumption. Yttrium oxide and neodymium oxide can inhibit the abnormal growth of aluminum oxide grains in the jadeite matrix material, ensuring the anti-bending strength of the ceramic core fiber reinforced synthetic jadeite. Dysprosium oxide can regulate the thermal expansion coefficient, reduce the interlayer stress, improve the thermal shock resistance, and reduce the risk of firing cracking. In addition, rare earth oxides also react with the surface of the ceramic reinforcing fiber to form chemical bonds (such as Al-O-La bonds), enhancing the interfacial bonding force between the ceramic fiber and the matrix and improving the interlayer shear strength.

[0035] In some specific embodiments, the mineralizer in the jadeite matrix material in the layered composite structure of multi-scale ceramic fiber reinforced synthetic jadeite can be 1 part, 2 parts, or 3 parts by weight.

[0036] In some specific embodiments, the particle sizes of aluminum oxide and silicon dioxide in the jadeite matrix material are independently 0.1~5 μm.

[0037] In some specific embodiments, by way of example, the particle size of aluminum oxide in the jadeite matrix material can be 0.1 μm, 0.25 μm, 0.5 μm, 0.75 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, as long as the particle size of aluminum oxide in the jadeite matrix material is within this range.

[0038] In some specific embodiments, by way of example, the particle size of silicon dioxide in the jadeite matrix material can be 0.1 μm, 0.25 μm, 0.5 μm, 0.75 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, as long as the particle size of silicon dioxide in the jadeite matrix material is within this range.

[0039] In some specific embodiments, the ceramic fiber reinforcement material includes chopped ceramic fibers and continuous ceramic fibers, wherein: The length of the chopped ceramic fibers is 50~800 μm, and the particle size of the chopped ceramic fibers is 0.5~30 μm; The length of the continuous ceramic fibers is 1.5~10 mm; The particle size of the continuous ceramic fibers is 0.5~30 μm; The aspect ratio of the continuous ceramic fibers ≥50.

[0040] In some specific embodiments, by way of example, the length of the chopped ceramic fibers can be 50 μm, 75 μm, 100 μm, 150 μm, 200 μm, 300 μm, 500 μm, 750 μm, 800 μm, as long as the length of the chopped ceramic fibers is within this range.

[0041] In some specific embodiments, by way of example, the particle size of the chopped ceramic fibers can be 0.5 μm, 1 μm, 2 μm, 5 μm, 10 μm, 20 μm, 25 μm, 30 μm, as long as the particle size of the chopped ceramic fibers is within this range.

[0042] In some specific embodiments, by way of example, the length of the continuous ceramic fibers can be 1.5 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7.5 mm, 8 mm, 9 mm, 10 mm, as long as the length of the continuous ceramic fibers is within this range.

[0043] In some specific embodiments, the continuous ceramic fibers and the chopped ceramic fibers are independently selected from one or more of alumina fibers, silicon carbide fibers, and mullite fibers.

[0044] In some specific embodiments, by way of example, the particle size of the continuous ceramic fibers can be 0.5 μm, 1 μm, 2 μm, 5 μm, 10 μm, 20 μm, 25 μm, 30 μm, as long as the particle size of the continuous ceramic fibers is within this range.

[0045] In some specific embodiments, the aspect ratio of the continuous ceramic fibers ≥ 50.

[0046] In some specific embodiments, the mass ratio of the chopped ceramic fibers to the continuous ceramic fibers is (1: 0.5 to 3). By way of example, the mass ratio of the chopped ceramic fibers to the continuous ceramic fibers can be 1: 0.5, 1: 0.75, 1: 1, 1: 1.25, 1: 1.5, 1: 1.75, 1: 2, 1: 2.5, 1: 3.

[0047] In some specific embodiments, the ceramic fibers used in the ceramic fiber reinforced material are selected from one or more of alumina fibers, silicon carbide fibers or mullite fibers.

[0048] In some specific embodiments, the colorant includes one or more of chromium sesquioxide, ferric oxide, titanium dioxide, manganese dioxide, cobalt ferrite, magnesium oxide, neodymium oxide, vanadium oxide.

[0049] In a specific embodiment, when the colorant contains chromium sesquioxide, Cr in the chromium sesquioxide 3+ enters the lattice of the corundum type structure (aluminum sesquioxide), and firing in an inert atmosphere can make the layered composite structure of the multi-scale ceramic fiber reinforced synthetic jade present a emerald green color, and at the same time can avoid Cr 3+ from being oxidized to Cr 6+ .

[0050] In a specific embodiment, when the colorant contains ferric oxide, Fe in the ferric oxide 3+ will combine with silicon dioxide in the jade matrix material to form hematite phase, making the jade present a yellow emerald visual effect. In particular, if fired under the condition of a reducing atmosphere, Fe 3+ will be reduced to Fe 2+， which can make the jade present a red emerald visual effect.

[0051] In some specific embodiments, the particle size of the colorant is 0.01 to 0.5 μm. By way of example, the particle size of the colorant can also be 0.01 μm, 0.05 μm, 0.1 μm, 0.25 μm, 0.3 μm, 0.4 μm, 0.5 μm, as long as the particle size of the colorant is within this range.

[0052] Another embodiment of the present invention provides a low-temperature sintering method for the above-mentioned layered composite structure of multi-scale ceramic fiber-reinforced synthetic jadeite, which specifically includes the following steps: S1. Mix the jadeite matrix material with the color developer and then ball-mill to obtain the jadeite matrix material coated with the color developer; S2. Mix the ceramic fiber reinforcing material with the silane coupling agent to obtain the modified ceramic fiber reinforcing material; S3. Mix the jadeite matrix material coated with the color developer, the modified ceramic fiber reinforcing material and the dispersant, and then obtain the prefabricated slurry under the treatment of an electric field and an ultrasonic field; S4. Fill the prefabricated slurry into the synthetic jadeite mold and perform gradient temperature firing to obtain the layered composite structure of multi-scale ceramic fiber-reinforced synthetic jadeite.

[0053] In some specific embodiments, the rotation speed of the ball-milling in step S1 is 300 - 500 rpm, the ball-milling time is 120 - 240 min, the grinding balls are zirconia grinding balls, and the diameter of the grinding balls is 3 - 10 mm. In this embodiment, in-situ bonding is adopted by ball-milling, and the color developer particles are embedded on the surface of the ceramic fiber-reinforced matrix, forming a tight combination between the color developer particles and the matrix of the layered composite structure of multi-scale ceramic fiber-reinforced synthetic jadeite.

[0054] In some specific embodiments, a planetary ball mill is used for ball-milling in step S1, and the rotation speed of the ball-milling is 300 - 500 rpm. As an example, the rotation speed of the ball-milling can be 300 rpm, 350 rpm, 400 rpm, 450 rpm, 500 rpm, as long as the rotation speed of the ball-milling meets the range.

[0055] In some specific embodiments, the ball-milling time in step S1 is 120 - 240 min. As an example, the ball-milling time can be 120 min, 150 min, 180 min, 210 min, 240 min, as long as the ball-milling time meets the range.

[0056] In some specific embodiments, the grinding balls used in step S1 are zirconia grinding balls, and the diameter of the grinding balls is 3 - 10 mm. As an example, the diameter of the grinding balls can be 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, as long as the diameter of the grinding balls meets the range.

[0057] In some specific embodiments, in step S1, in order to make the jadeite matrix material and the color developer combine more fully, 1 - 5 parts by weight of stearate can also be added as a dispersant and a lubricant.

[0058] In some specific embodiments, the stearate in step S1 is selected from one or more of zinc stearate, calcium stearate, and magnesium stearate.

[0059] In some specific embodiments, 1 to 5 parts by weight of stearate is added in step S1. As an example, the weight parts of stearate that can be added are 1, 2, 3, 4, and 5, as long as the weight parts of stearate are within this range.

[0060] In some specific embodiments, the silane coupling agent used in step S2 is KH-550 or KH-560. After the ceramic fiber reinforcing material is treated with the silane coupling agent, the surface can carry natural positive charges containing amino groups. At the same time, the silane coupling agent selected in this embodiment will decompose into silicon dioxide, water, and ammonia during the subsequent firing process. Among them, silicon dioxide can be incorporated into the jadeite matrix material to enhance the interfacial bonding ability, while ammonia and water can overflow during the firing process and will not introduce additional impurities.

[0061] In some specific embodiments, the dosage of the silane coupling agent is 1 to 5 parts by weight. As an example, the dosage of the silane coupling agent can be 1 part, 2 parts, 3 parts, 4 parts, or 5 parts, as long as the dosage of the silane coupling agent is within this range.

[0062] In some specific embodiments, the dispersant used in step S3 is any one of sodium silicate aqueous solution, sodium hexametaphosphate aqueous solution, sodium citrate aqueous solution, and sodium ethylenediaminetetraacetate aqueous solution. Among them, the sodium ions generated by the ionization of sodium hexametaphosphate form a double electric layer, enhancing the electrostatic repulsion between particles and preventing agglomeration. Sodium citrate can adsorb on the particle surface through carboxyl groups to form steric hindrance and inhibit agglomeration. In addition, sodium citrate also has good compatibility with rare earth metal oxides (such as lanthanum oxide) used as mineralizing agents to avoid precipitation.

[0063] In some specific embodiments, the usage amount of the dispersant used in step S3 is 1 to 5 parts by weight. As an example, the usage amount of the dispersant can be 1 part, 2 parts, 3 parts, 4 parts, or 5 parts, as long as the usage amount of the dispersant is within this range.

[0064] In some specific embodiments, the pH of the dispersant used in step S3 is 8 to 11. As an example, the pH of the dispersant can be 8, 8.5, 9, 9.5, 10, 10.5, or 11, as long as the pH of the dispersant is within this range.

[0065] In some specific embodiments, the conductivity of the dispersant used in step S3 is 50 to 100 μS / cm. As an example, the conductivity can be 50 μS / cm, 60 μS / cm, 70 μS / cm, 75 μS / cm, 80 μS / cm, 85 μS / cm, 90 μS / cm, or 100 μS / cm, as long as the conductivity of the dispersant is within this range.

[0066] In some specific embodiments, the electric field strength in step S3 is 5 - 20 V / cm. By way of example, the electric field strength can be 5 V / cm, 8 V / cm, 10 V / cm, 12 V / cm, 15 V / cm, 17 V / cm, 20 V / cm. As long as the electric field strength is within this range.

[0067] In some specific embodiments, the electric field action time in step S3 is 10 - 30 min. By way of example, the electric field action time can be 10 min, 15 min, 20 min, 25 min, 30 min. As long as the electric field action time is within this range.

[0068] In some specific embodiments, the electric field energy consumption in step S3 is 0.8 - 1.5 kWh / m³. By way of example, the electric field energy consumption can be 0.8 kWh / m³, 1.0 kWh / m³, 1.2 kWh / m³, 1.4 kWh / m³, 1.5 kWh / m³. As long as the electric field energy consumption is within this range.

[0069] In some specific embodiments, the frequency of the ultrasonic field in step S3 is 30 - 50 kHz. By way of example, the frequency of the ultrasonic field can be 30 kHz, 35 kHz, 40 kHz, 45 kHz, 50 kHz. As long as the ultrasonic frequency of the ultrasonic field is within this range.

[0070] In some specific embodiments, the power density of the ultrasonic field in step S3 is 50 - 200 W / L. By way of example, the power density of the ultrasonic field can be 50 W / L, 75 W / L, 100 W / L, 125 W / L, 150 W / L, 175 W / L, 200 W / L. As long as the power density of the ultrasonic field is within this range.

[0071] In this embodiment, the gradient distribution and directional arrangement of ceramic fibers in the prefabricated slurry are achieved through the synergistic dispersion of the electric field - ultrasonic wave, and the mechanical properties can be significantly improved after firing and forming.

[0072] In some specific embodiments, the gradient temperature - rise firing in step S4 includes the following steps: The prefabricated slurry is heated from room temperature to 500 - 700 °C at a heating rate of 3 - 8 °C / min and kept warm for 60 - 120 min, and then heated to 800 - 950 °C at a heating rate of 0.2 - 0.8 °C / min and kept warm for 180 - 360 min.

[0073] In some specific embodiments, the prefabricated slurry loaded in the jade mold is fired and formed by gradient temperature - rise firing in step S4. Specifically, the heating process in the first stage is as follows: The prefabricated slurry is heated from room temperature to 500 - 700°C at a heating rate of 3 - 8°C / min and kept warm for 60 - 120 min, and then heated to 800 - 950°C at a heating rate of 0.2 - 0.8°C / min and kept warm for 180 - 360 min.

[0074] In some specific embodiments, the heating rate in the first stage of step S4 is 3 - 8°C / min. By way of example, the heating rate in the first stage can be 3°C / min, 4°C / min, 5°C / min, 6°C / min, 7°C / min, 8°C / min, as long as the heating rate in the first stage meets the range.

[0075] In some specific embodiments, the heating end point in the first stage of step S4 is 500 - 770°C. By way of example, the heating end point in the first stage can be 500°C, 525°C, 550°C, 575°C, 600°C, 625°C, 650°C, 675°C, 700°C, as long as the heating end point in the first heating stage meets the range.

[0076] In some specific embodiments, the heat preservation time in the first stage of step S4 is 60 - 120 min. By way of example, the heat preservation time in the first stage can be 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, 120 min, as long as the heating time in the first stage meets the range.

[0077] In some specific embodiments, the heating rate in the second stage of step S4 is 0.2 - 0.8°C / min. By way of example, the heating rate in the second stage can be 0.2°C / min, 0.4°C / min, 0.5°C / min, 0.6°C / min, 0.8°C / min, as long as the heating rate in the second stage meets the range.

[0078] In some specific embodiments, the heat preservation time in the second stage of step S4 is 180 - 360 min. By way of example, the heat preservation time in the second stage can be 180 min, 200 min, 210 min, 240 min, 260 min, 270 min, 300 min, 330 min, 350 min, 360 min, as long as the heat preservation time in the second stage meets the range.

[0079] The present invention will be further described below through specific embodiments: Flexural strength: ASTM D790 (three - point bending method, specimen size 3×4×40 mm).

[0080] Fracture toughness: ASTM E399 (single - edge notched beam method, pre - cracked length 2 mm).

[0081] Light transmittance: ASTM D1003 (integrating sphere method, wavelength 550 nm). Example 1

[0082] The emerald green jade prepared in this example contains the following raw materials: Jade matrix material: 100 g, where: Al2O3: 60 g (particle size 0.5 μm); SiO2: 35 g (particle size 0.3 μm); Mineralizer (Nd2O3): 5 g.

[0083] Ceramic fiber reinforcement material: 25 g, where: Chopped alumina fiber: 10 g (length 200 μm, particle size 5 μm); Continuous silicon carbide fiber: 15 g (length 5 mm, particle size 10 μm, aspect ratio ≥ 50); Color developer: Cr2O3: 3 g (particle size 50 nm).

[0084] Preparation method: Ball milling and coating: Mix the matrix material with Cr2O3 and magnesium stearate and ball mill (400 rpm, 3 h, zirconia grinding balls with a diameter of 5 mm), and the amount of magnesium stearate used is 5 g.

[0085] Fiber modification: Treat the fiber with KH-550 silane coupling agent, and the amount of coupling agent used is 3 g.

[0086] Electric field-ultrasonic dispersion: Dispersion liquid: Sodium silicate solution (pH = 10, conductivity 80 μS / cm).

[0087] Electric field strength: 15 V / cm, ultrasonic frequency: 40 kHz, ultrasonic power density: 150 W / L, treatment time 20 min.

[0088] The fibers are oriented in the electric field (orientation angle deviation ≤ 15°), and the ultrasonic cavitation effect inhibits agglomeration, forming a fiber volume fraction gradient (bottom layer 35% → surface layer 15%).

[0089] Gradient sintering: First stage: Keep at 600 °C for 1.5 h (N2 atmosphere); Second stage: Keep at 900 °C for 5 h (Ar atmosphere).

[0090] Performance test: Flexural strength: 430 MPa (test standard: ASTM D790); Fracture toughness: 4.2 MPa·m(¹ / ²) (Testing standard: ASTM E399). Example 2

[0091] The red jadeite - yellow jadeite gradient synthetic jadeite prepared in this example contains the following raw materials: Jadeite matrix material: 90 g, among which: Al2O3: 55 g (particle size 1 μm) SiO2: 30 g (particle size 0.5 μm) Mineralizer (La2O3): 5 g.

[0092] Ceramic fiber reinforcement material: 30 g, among which: short chamosite fiber: 12 g (length 500 μm, particle size 10 μm) Continuous alumina fiber: 18 g (length 8 mm, particle size 20 μm, length - diameter ratio ≥ 50) Color developer: Fe2O3: 4 g (particle size 100 nm) + TiO2 1 g (particle size 200 nm).

[0093] Preparation method: Ball - milling coating: The matrix material is mixed with the color developer and calcium stearate and then ball - milled (350 rpm, 4 h, ball diameter 8 mm), and the dosage of calcium stearate is 4 g.

[0094] Fiber modification: The fiber is treated with KH - 560 silane coupling agent, and the dosage is 4 g.

[0095] Electric field - ultrasonic dispersion: Electric field strength: 10 V / cm, ultrasonic frequency: 35 kHz, ultrasonic power density: 100 W / L, treatment time 25 min.

[0096] The electric field guides the fibers to be distributed in a gradient (bottom layer 40% red jadeite layer → surface layer 15% yellow jadeite layer), and ultrasonic waves refine the dispersion of the color developer.

[0097] Gradient sintering: First stage: Keep the temperature at 700 °C for 1 h (H2 3% reducing atmosphere); Second stage: Keep the temperature at 850 °C for 4 h (N2 atmosphere).

[0098] Performance test Flexural strength: 390 MPa Fracture toughness: 3.7 MPa·m(¹ / ²) Example 3

[0099] The blue water jadeite prepared in this example contains the following raw materials: Jadeite matrix material: 110 g, among which: Al2O3: 65 g (particle size 0.2 μm) SiO2: 40 g (particle size 0.4 μm) Mineralizer (Y2O3): 5 g.

[0100] Ceramic fiber reinforcement: 20 g, among which: Short-cut silicon carbide fiber: 8 g (length 100 μm, particle size 2 μm) Continuous mullite fiber: 12 g (length 3 mm, particle size 5 μm, length-diameter ratio ≥ 60) Color developer: Co3O4 2 g (particle size 30 nm) + MgO 1 g (particle size 150 nm) Preparation method Ball milling coating: The matrix material is mixed with the color developer and zinc stearate and then ball milled (450 rpm, 2.5 h, ball diameter 6 mm), and the dosage of zinc stearate is 3 g.

[0101] Fiber modification: The fiber is treated with KH-550, and the dosage is 2 g.

[0102] Electric field-ultrasonic dispersion: Electric field strength: 20 V / cm, ultrasonic frequency: 50 kHz, ultrasonic power density: 200 W / L, treatment time 15 min.

[0103] The fibers are arranged in parallel to form a highly transparent layer (volume fraction 10%), and ultrasonic waves inhibit the agglomeration of Co3O4.

[0104] Gradient sintering: The first stage: Keep the temperature at 500 °C for 2 h (air oxidation of Co²⁺ → Co³⁺); The second stage: Keep the temperature at 950 °C for 3 h (N2 atmosphere).

[0105] Performance test Flexural strength: 410 MPa Fracture toughness: 4.0 MPa·m(¹ / ²) Light transmittance: 88% (simulating ice-grade jadeite). Comparative example

[0106] To further prove the mechanical properties of the layered composite structure of the multi-scale ceramic fiber-reinforced synthetic jadeite prepared by the present invention, a comparative test is now carried out. The components of the comparative example are exactly the same as those of Example 1, and the difference lies in the preparation method, which is specifically as follows: Preparation of precast slurry: Cancel the electric field-ultrasonic treatment and use the centrifugation method (3000 rpm, 15 min), and the fiber volume fraction is evenly distributed (25%).

[0107] The fibers are randomly distributed and have no directional arrangement.

[0108] Sintering process: the same as in Example 1.

[0109] Performance test Flexural strength: 220 MPa (↓49%) Fracture toughness: 2.3 MPa·m(¹ / ²) (↓45%).

[0110] It can be seen from the comparison that: In Examples 1 to 3, the fiber gradient distribution and orientation arrangement are achieved through the synergistic dispersion of electric field - ultrasound, significantly improving the mechanical properties (flexural strength > 390 MPa, fracture toughness > 3.7 MPa·m(¹ / ²)). However, due to the uneven fiber distribution in the comparative example, the performance has decreased significantly. The present invention precisely regulates the fiber microstructure through the electric field, breaking through the performance bottleneck of traditional synthetic jade, and has significant industrial application value.

[0111] It should be understood that the application of the present invention is not limited to the above examples. For those of ordinary skill in the art, improvements or transformations can be made according to the above description, and all such improvements and transformations should fall within the protection scope of the appended claims of the present invention.

Claims

1. The layered composite structure of multi-scale ceramic fiber reinforced synthetic jadeite, characterized in that, Comprises the following components by weight parts: Jade matrix material 75 - 125 parts Ceramic fiber reinforcing material 10 - 35 parts Color developer 1 - 5 parts.

2. The layered composite structure of multi-scale ceramic fiber reinforced synthetic jade according to claim 1, wherein The jade matrix material comprises the following components by weight parts: Aluminum oxide 50 - 70 parts Silicon dioxide 25 - 45 parts Mineralizer 1 - 3 parts; The particle sizes of the aluminum oxide and silicon dioxide are independently 0.1 - 5μm.

3. The layered composite structure of multi-scale ceramic fiber reinforced synthetic jade according to claim 1, wherein The ceramic fiber reinforcing material includes chopped ceramic fibers and continuous ceramic fibers, wherein: The length of the chopped ceramic fibers is 50 - 800μm, and the particle size of the chopped ceramic fibers is 0.5 - 30μm; The length of the continuous ceramic fibers is 1.5 - 10mm; The particle size of the continuous ceramic fibers is 0.5 - 30μm; The aspect ratio of the continuous ceramic fibers ≥ 50; The mass ratio of the chopped ceramic fibers to the continuous ceramic fibers is (1:0.5 - 3).

4. The layered composite structure of multi-scale ceramic fiber reinforced synthetic jade according to claim 1, characterized in that, The color developer includes one or more of chromium trioxide, iron(III) oxide, titanium dioxide, manganese dioxide, cobalt(II,III) oxide, magnesium oxide, neodymium oxide, vanadium oxide; The particle size of the color developer is 0.01 - 0.5μm.

5. The layered composite structure of multi-scale ceramic fiber reinforced synthetic jade according to claim 2, wherein The mineralizer is one or more of lanthanum oxide, cerium oxide, neodymium oxide, yttrium oxide, europium oxide, dysprosium oxide.

6. A low-temperature sintering method for a layered composite structure of multi-scale ceramic fiber-reinforced synthetic jade according to any one of claims 1 to 5, characterized in that, Includes the following steps: Mix the jade matrix material and the color developer and then ball mill to obtain the jade matrix material coated with the color developer; Mix the ceramic fiber reinforcing material and the silane coupling agent to obtain the modified ceramic fiber reinforcing material; Mix the jade matrix material coated with the color developer, the modified ceramic fiber reinforcing material and the dispersant, and then obtain the pre - formed slurry under the treatment of an electric field and an ultrasonic field; Fill the pre - formed slurry into a synthetic jade mold and perform gradient temperature firing to obtain a multi - scale ceramic fiber reinforced synthetic jade layered composite structure.

7. The low-temperature sintering method for the layered composite structure of multi-scale ceramic fiber-reinforced synthetic jadeite according to claim 6, characterized in that, The ball mill rotation speed is 300 - 500rpm, the ball mill time is 120 - 240min, the grinding balls are zirconia grinding balls, and the diameter of the grinding balls is 3 - 10mm.

8. The low-temperature sintering method of the layered composite structure of multi-scale ceramic fiber reinforced synthetic jade according to claim 6, characterized in that The dispersant is any one of sodium silicate aqueous solution, sodium hexametaphosphate aqueous solution, sodium citrate aqueous solution, sodium ethylenediaminetetraacetate aqueous solution; The pH of the dispersant is 8 - 11; The conductivity of the dispersant is 50 - 100μS / cm.

9. The low-temperature sintering method of the layered composite structure of multi-scale ceramic fiber-reinforced synthetic jade according to claim 6, characterized in that, The electric field strength is 5 - 20V / cm; The electric field action time is 10 - ​ ​ ​ 10. The low-temperature sintering method for the layered composite structure of multi-scale ceramic fiber reinforced synthetic jadeite according to claim 6, characterized in that ​ ​

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