A metal carbide / silicon carbide composite ceramic organic precursor, and a preparation method and application thereof

Abstract

The application discloses a metal carbide / silicon carbide composite ceramic organic precursor and a preparation method and application thereof, and relates to the technical field of composite ceramic preparation. The method comprises the following steps: under an inert atmosphere, a metal carbide precursor and a liquid hyperbranched polycarbosilane are added into a cosolvent, stirring is conducted at room temperature, and the solvent is removed by vacuum distillation to obtain a solid, which is the metal carbide / silicon carbide composite ceramic organic precursor. The application has the characteristics of simple raw materials, simple process, short preparation period, low cost, novel precursor molecular structure, controllable ceramic phase composition, good high-temperature oxidation resistance, high ceramic yield and good solubility. The application solves the problems of complex reaction route, poor product performance and solubility in the prior art.

Description

Technical Field

[0001] This invention relates to the field of multiphase ceramic preparation technology, specifically to a metal carbide / silicon carbide multiphase ceramic organic precursor, its preparation method, and its application. Background Technology

[0002] Ultra-high temperature ceramics (UHTC) can withstand extreme environments such as long-duration supersonic flight, atmospheric reentry, transatmospheric flight, and rocket propulsion systems. They can be applied to high-temperature thermal protection components or parts, such as aircraft nose cones, wing leading edges, and engine hot sections. Ultra-high temperature metal carbides (MC = Ta, Nb, Zr, Ti) possess unique properties such as high melting point (>3000℃), high hardness, high elastic modulus, high density, and good chemical stability. They are considered important members of the UHTC family. These properties enable MC (M = Ta, Nb, Zr, Ti) to be used in aerospace, metallurgy, and machinery fields, with broad application prospects in areas such as rocket nozzles, engines, high-performance cutting tools, cold stamping dies, and aerospace propulsion systems. However, UHTC has disadvantages such as low fracture toughness and poor oxidation resistance at medium and low temperatures (1200-1400℃), which limits its application in the aerospace field. Introducing a second phase of silicon carbide (SiC) into UHTC to prepare ultra-high temperature metal carbide MC (M=Ta, Nb, Zr, Ti) / SiC composite ceramics is the most effective way to improve its low-temperature oxidation resistance. In this type of composite ceramic, SiC can form a dense protective layer containing silicon dioxide in a high-temperature environment rich in water and oxygen, which hinders the further diffusion of oxygen in the ceramic and improves the low-temperature oxidation resistance of MC (M=Ta, Nb, Zr, Ti).

[0003] Polymer precursor conversion (PDC) is an advanced method for preparing structural and functional ceramics by preparing ceramics through polymer molding and pyrolysis. It allows for the control of ceramic composition (chemical composition and phase composition) and microstructure (nano / micro structure) at the atomic scale through polymer precursor design to achieve desired properties. Polymer precursors are key raw materials for the preparation of MC (M = Ta, Nb, Zr, Ti) / SiC multiphase ceramics via PDC. Due to the high difficulty in synthesizing MC precursors, there are few published reports on the synthesis methods of such multiphase ceramic precursors. Junying Zhan et al. used tetrabutyl titanate to modify allyl polycarbosilane (AHPCS) to obtain SiC / TiC ceramic precursors, with a maximum Ti addition of only 5%; Fen Li et al. used niobium pentachloride and AHPCS as raw materials, using a large amount of chloroform as a solvent, to obtain NbC-SiC-C precursors. At a niobium pentachloride to AHPCS mass ratio of 1:1, the resulting organoceramic precursors were neither dissolved nor melted; Yujing Yang et al. used a similar method to prepare SiC-TaC-C precursors using tantalum pentachloride to modify AHPCS. When the tantalum pentachloride to AHPCS mass ratio was 1:2 and the sintering temperature was 1600℃, the carbon TaC and SiC components in the crystalline phase were 31.72 wt% and 68.28 wt%, respectively, with SiC as the main phase; Le Yang et al. prepared SiC / ZrC / C ceramic precursors by reacting zirconium dichlorocerocene with AHPCS. Due to the poor solubility of zirconium dichlorocerocene, the reaction required a large amount of chloroform as a solvent, and the maximum addition amount of zirconium dichlorocerocene was only 33.3 wt%, resulting in a Zr content of less than 10% in the final ceramic.

[0004] In summary, the existing preparation methods usually involve introducing small molecule metal compounds into liquid hyperbranched polycarbosilanes to introduce ultra-high temperature MC (M = Ta, Nb, Zr, Ti) phases into SiC ceramics. These methods have the following drawbacks: (1) The small molecule metal compounds have poor solubility and require a large amount of solvent for the reaction; (2) The small molecule metal compounds have poor reactivity with polycarbosilanes, resulting in a low MC phase content in the final ceramic, which affects the high temperature resistance of the material; (3) After the small molecule metal compounds react with polycarbosilanes, they form precursors of cross-linked structures, which are in a non-melting and non-dissolving state, lose their processing properties, and cannot be used to prepare fiber-reinforced ceramic matrix composites (CMCs) by polymer impregnation pyrolysis (PIP). Summary of the Invention

[0005] To address the aforementioned technical problems, the present invention aims to provide a metal carbide / silicon carbide multiphase ceramic organic precursor, its preparation method, and its application, thereby solving the problems of complex reaction routes and poor product performance and solubility in existing methods for preparing multiphase ceramic organic precursors.

[0006] The technical solution of this invention to solve the above-mentioned technical problems is as follows: A method for preparing a metal carbide / silicon carbide multiphase ceramic organic precursor is provided, comprising the following steps:

[0007] (1) Under an inert atmosphere, the metal carbide precursor and liquid hyperbranched polycarbosilane are added to a co-solvent and stirred at room temperature for 0.5-1h to obtain a reaction solution;

[0008] (2) Continue under the inert atmosphere described in step (1), remove the solvent from the reaction solution obtained in step (1) by vacuum distillation to obtain a solid, which is the metal carbide / silicon carbide multiphase ceramic organic precursor.

[0009] Based on the above technical solution, the present invention can be further improved as follows:

[0010] Furthermore, in step (1), the inert atmosphere is nitrogen or argon.

[0011] Furthermore, the inert atmosphere was achieved using a Schlenk apparatus.

[0012] Furthermore, the inert atmosphere is achieved by the following method: evacuating the Schlenk apparatus to 0.05-0.12 MPa, introducing inert gas, and then repeating the evacuation and inert gas introduction 3-6 times, followed by continuous introduction of inert gas, thus achieving the inert atmosphere.

[0013] The beneficial effects of adopting the above-mentioned further technical solution are as follows: the inert atmosphere ensures that no oxygen is introduced during the reaction process, thereby reducing the oxygen content in the precursor and ultimately improving the ceramic yield of the precursor.

[0014] Furthermore, in step (1), the mass ratio of the metal carbide precursor, the liquid hyperbranched polycarbosilane and the co-solvent is 1-9:1-9:3-10.

[0015] The beneficial effects of adopting the above-mentioned further technical solution are: the mass ratio range of metal carbide precursor and liquid hyperbranched polycarbosilane is wide, ensuring that the mass ratio of metal carbide and silicon carbide in the multiphase ceramic is adjustable within a wide range.

[0016] Furthermore, in step (1), the liquid hyperbranched polycarbosilane is a liquid hyperbranched polycarbosilane containing carbon-carbon unsaturated bonds.

[0017] The beneficial effects of adopting the above-mentioned further technical solution are as follows: the liquid hyperbranched polycarbosilane contains carbon-carbon unsaturated bonds that can undergo cross-linking reactions with the carbon-carbon double bonds in the metal carbide precursor at temperatures above 80°C, thereby improving the final ceramic yield.

[0018] Furthermore, the liquid hyperbranched polycarbosilane is vinyl polycarbosilane, allyl polycarbosilane, ethynyl polycarbosilane, or propargyl polycarbosilane.

[0019] The beneficial effects of adopting the above-mentioned further technical solution are as follows: the vinyl, allyl, ethynyl or propargyl groups contained in the liquid hyperbranched polycarbosilane are all carbon-carbon unsaturated bonds, which can undergo cross-linking reaction with the carbon-carbon double bonds contained in the metal carbide precursor at temperatures above 80°C, thereby improving the final ceramic yield.

[0020] Furthermore, in step (1), the metal carbide precursor is a tantalum carbide precursor, a niobium carbide precursor, a zirconium carbide precursor, or a titanium carbide precursor.

[0021] Furthermore, the metal carbide precursor is prepared by the following method:

[0022] S1: In an inert gas protective atmosphere, add the metal source to the carbon source, stir at room temperature for 0.5-2h, then add alcohol, and react at 40-100℃ for 1-2h to obtain a reaction solution; wherein, the molar ratio of metal source, carbon source and alcohol is 1:2-4:5-20.

[0023] S2: Continue in the inert gas protective atmosphere described in step S1 to remove the solvent from the reaction solution obtained in step S1, and then vacuum dry it at 60-80℃ for 3-12 hours to obtain a solid, which is the metal carbide organic precursor.

[0024] Furthermore, in step S1, the metal source is a tantalum source, a niobium source, a zirconium source, or a titanium source.

[0025] Furthermore, the tantalum source is tantalum chloride, tantalum oxychloride, pentamethanol, pentamethanol, pentamethanol, pentamethanol, pentamisopropoxide, pentamisopropoxide, pentamisobutoxide, pentamisobutoxide, or pentampentoxide; the niobium source is niobium chloride, niobium oxychloride, pentamethanol, pentamethanol, pentamethanol, pentamethanol, pentamethanol, pentamisopropoxide, pentamisopropoxide, pentamisobutoxide, pentamisobutoxide, or pentampentoxide; the zirconium source is zirconium chloride, zirconium oxychloride, tetramethanol, tetraethanol, tetrapropoxide, tetraisopropoxide, tetrabutoxide, tetraisobutoxide, or tetrapentoxide; and the titanium source is titanium chloride, titanium oxychloride, titanium tetramethanol, titanium tetraethanol, titanium tetrapropoxide, titanium tetraisopropoxide, titanium tetrabutoxide, or tetrapentoxide.

[0026] Furthermore, in step S1, the carbon source is methacrylic anhydride or acrylic anhydride.

[0027] Furthermore, in step S1, the alcohol is methanol, ethanol, propanol, or butanol.

[0028] Furthermore, in step S2, the solvent is removed by vacuum distillation.

[0029] Furthermore, vacuum distillation was performed at temperatures ranging from room temperature to 80°C.

[0030] Furthermore, the vacuum degree of the reduced pressure distillation is 0.05 MPa.

[0031] Furthermore, in step (1), the co-solvent is a mixture of solvent one and solvent two, where solvent one is methanol, ethanol, propanol or butanol, and solvent two is tetrahydrofuran, acetone, butanone, dichloroethane, dichloromethane, trichloromethane or toluene.

[0032] Furthermore, in step (2), the sample is distilled under reduced pressure at room temperature to 80°C.

[0033] Furthermore, the vacuum degree of the reduced pressure distillation is 0.05 MPa.

[0034] The present invention also provides a metal carbide / silicon carbide multiphase ceramic organic precursor prepared by the above-mentioned method for preparing the metal carbide / silicon carbide multiphase ceramic organic precursor.

[0035] The present invention also provides the application of the above-mentioned metal carbide / silicon carbide multiphase ceramic organic precursor in the preparation of metal carbide / silicon carbide multiphase ceramics.

[0036] Furthermore, the aforementioned metal carbide / silicon carbide multiphase ceramic organic precursor is used as an impregnating agent for fiber-reinforced ceramic matrix composites.

[0037] The present invention has the following beneficial effects:

[0038] 1. The metal carbide (MC precursor) of this invention contains carbon-carbon double bonds and has a novel structure. The method of this invention only requires adjusting the mass ratio of the MC precursor and liquid hyperbranched polycarbosilane to achieve the control of the composition of MC (M = Ta, Nb, Zr, Ti) and SiC in the final MC / SiC composite ceramic, which can improve the oxidation resistance of MC ceramic materials at high temperatures.

[0039] 2. The molecular structure of the multiphase ceramic organic precursor of the present invention contains carbon-carbon double bonds that can be self-crosslinked at low temperature (derived from MC precursor and liquid hyperbranched polycarbosilane). The carbon-carbon double bonds in the precursor can achieve thermal crosslinking and curing at 80-100℃, thereby improving its ceramic yield.

[0040] 3. The multiphase ceramic organic precursor of the present invention is readily soluble in mixed co-solvents, and its pyrolysis products at 1500°C are free of oxides. It is suitable as an impregnating agent for the preparation of fiber-reinforced ceramic matrix composites (CMC) by polymer impregnation pyrolysis (PIP), and has important applications in the field of thermal protection materials such as spacecraft shells.

[0041] 4. This invention features readily available raw materials, simple process, short preparation cycle, low cost, novel precursor molecular structure, controllable ceramic phase composition, good high-temperature oxidation resistance, high ceramic yield, and good solubility. Attached Figure Description

[0042] Figure 1 The FT-IR infrared spectrum of the multiphase ceramic organic precursor in Example 1;

[0043] Figure 2 The FT-IR infrared spectrum of the multiphase ceramic organic precursor in Example 2;

[0044] Figure 3 The FT-IR infrared spectrum of the multiphase ceramic organic precursor in Example 3;

[0045] Figure 4 The FT-IR infrared spectrum of the multiphase ceramic organic precursor in Example 4;

[0046] Figure 5 Thermogravimetric analysis (TGA) curves of the multiphase ceramic organic precursor in Example 1;

[0047] Figure 6 Thermogravimetric analysis (TGA) curves of the multiphase ceramic organic precursor in Example 2;

[0048] Figure 7 Thermogravimetric analysis (TGA) curves of the multiphase ceramic organic precursor in Example 3;

[0049] Figure 8 Thermogravimetric analysis (TGA) curves of the multiphase ceramic organic precursor in Example 4;

[0050] Figure 9 The image shows the XRD pattern of the pyrolysis products of the multiphase ceramic organic precursor in Example 1.

[0051] Figure 10 XRD pattern of the pyrolysis products of the multiphase ceramic organic precursor in Example 2;

[0052] Figure 11 The image shows the XRD pattern of the pyrolysis products of the multiphase ceramic organic precursor in Example 3.

[0053] Figure 12 XRD pattern of the pyrolysis products of the multiphase ceramic organic precursor in Example 4;

[0054] Figure 13 for Figure 9 TEM image of the product;

[0055] Figure 14 for Figure 10 TEM image of the product;

[0056] Figure 15 for Figure 11 TEM image of the product;

[0057] Figure 16 for Figure 12 TEM image of the product. Detailed Implementation

[0058] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are for illustrative purposes only and are not intended to limit the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer should be followed. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0059] In the following embodiments, the inert gas protective atmosphere is provided by a Schlenk apparatus, which uses a three-necked flask as the main reaction equipment. The first port is used to introduce the protective gas, the second port is connected to a constant pressure funnel for adding raw materials, and the third port is connected to a reflux device and then to a tail gas treatment device.

[0060] Example 1:

[0061] A metal carbide / silicon carbide (TaC / SiC) multiphase ceramic organic precursor is prepared by the following steps:

[0062] (1) Evacuate the three-necked flask to 0.05 MPa, introduce argon gas, and then continue to evacuate to 0.05 MPa and introduce argon gas, repeating 3 times; then continue to introduce argon gas into the three-necked flask to achieve an inert gas protective atmosphere.

[0063] (2) In an argon protective atmosphere, tantalum source (tantalum chloride) was added to carbon source (methacrylic anhydride), stirred at room temperature for 0.5 h, and then alcohol (anhydrous methanol) was added. The mixture was reacted at 40 °C for 2 h to obtain a yellowish-brown transparent solution, i.e., the reaction solution; wherein the molar ratio of tantalum source, carbon source and alcohol was 1:2:20.

[0064] (3) Continue to use a rotary evaporator to remove the solvent from the reaction solution obtained in step (2) under reduced pressure at room temperature (vacuum degree is 0.05MPa) in an argon protective atmosphere, and then dry it in a vacuum drying oven at 60℃ for 12h to obtain a light yellow solid, which is the metal carbide precursor (TaC precursor).

[0065] (4) Continue to add the metal carbide precursor (TaC precursor) obtained in step (3) and liquid hyperbranched polycarbosilane (vinyl polycarbosilane) to the co-solvent (a mixture of anhydrous methanol and anhydrous tetrahydrofuran) under an argon protective atmosphere, and stir at room temperature for 0.5 h to obtain a brownish solution, i.e., the reaction solution; wherein the mass ratio of metal carbide precursor, liquid hyperbranched polycarbosilane and co-solvent is 1:1:5;

[0066] (5) Continue to remove the solvent from the reaction solution obtained in step (4) under a protective atmosphere of argon by rotary evaporator at room temperature by vacuum distillation (vacuum degree of 0.05MPa) to obtain a brown solid, which is the metal carbide / silicon carbide (TaC / SiC) multiphase ceramic organic precursor.

[0067] Example 2:

[0068] A metal carbide / silicon carbide (NbC / SiC) multiphase ceramic organic precursor is prepared by the following steps:

[0069] (1) Evacuate the three-necked flask to 0.12 MPa, introduce nitrogen gas, then continue to evacuate to 0.05 MPa and introduce nitrogen gas, repeat 6 times; then continue to introduce nitrogen gas into the three-necked flask to achieve an inert gas protective atmosphere.

[0070] (2) In a nitrogen protective atmosphere, niobium source (niobium chloride) was added to carbon source (acrylic anhydride), stirred at room temperature for 2 hours, and then alcohol (anhydrous propanol) was added. The mixture was reacted at 80°C for 1 hour to obtain a reddish-brown transparent solution, i.e., the reaction solution; wherein the molar ratio of niobium source, carbon source and alcohol was 1:4:5.

[0071] (3) Continue to use a nitrogen protective atmosphere to remove the solvent from the reaction solution obtained in step (2) by rotary evaporator at 60°C by vacuum distillation (vacuum degree is 0.05MPa), and then dry it in a vacuum drying oven at 80°C for 3h to obtain a brown solid, which is the metal carbide precursor (NbC precursor).

[0072] (4) Continue to add the metal carbide precursor (NbC precursor) obtained in step (3) and the liquid hyperbranched polycarbosilane (allyl polycarbosilane) to the co-solvent (a mixture of anhydrous ethanol and anhydrous acetone) under a nitrogen protective atmosphere, and stir at room temperature for 0.5 h to obtain a brownish-brown solution, i.e., the reaction solution; wherein the mass ratio of the metal carbide precursor, the liquid hyperbranched polycarbosilane and the co-solvent is 1:9:10;

[0073] (5) Continue to remove the solvent from the reaction solution obtained in step (4) under a nitrogen protective atmosphere by rotary evaporator at room temperature by vacuum distillation (vacuum degree of 0.05MPa) to obtain a brown solid, which is the metal carbide / silicon carbide (NbC / SiC) multiphase ceramic organic precursor.

[0074] Example 3:

[0075] A metal carbide / silicon carbide (ZrC / SiC) multiphase ceramic organic precursor is prepared by the following steps:

[0076] (1) Evacuate the three-necked flask to 0.08 MPa, introduce nitrogen gas, and then continue to evacuate to 0.08 MPa and introduce nitrogen gas, repeating 4 times; then continue to introduce nitrogen gas into the three-necked flask to achieve an inert gas protective atmosphere.

[0077] (2) Under a nitrogen protective atmosphere, zirconium source (zirconium chloride) is added to carbon source (acrylic anhydride), stirred at room temperature for 1 h, and then alcohol (anhydrous butanol) is added. The mixture is reacted at 100 °C for 1.5 h to obtain a brown transparent solution, i.e., the reaction solution; wherein the molar ratio of zirconium source, carbon source and alcohol is 1:3:15.

[0078] (3) Continue to use a nitrogen protective atmosphere to remove the solvent from the reaction solution obtained in step (2) by rotary evaporator at 80°C by vacuum distillation (vacuum degree is 0.05MPa), and then dry it in a vacuum drying oven at 70°C for 8 hours to obtain a light yellow solid, which is the metal carbide precursor (ZrC precursor).

[0079] (4) Continue to add the metal carbide precursor (ZrC precursor) obtained in step (3) and liquid hyperbranched polycarbosilane (ethynyl polycarbosilane) to the co-solvent (a mixture of anhydrous propanol and anhydrous toluene) under an argon protective atmosphere, and stir at room temperature for 1 hour to obtain a brownish-brown solution, i.e., the reaction solution; wherein, the mass ratio of metal carbide precursor, liquid hyperbranched polycarbosilane and co-solvent is 9:1:10;

[0080] (5) Continue to remove the solvent from the reaction solution obtained in step (4) under a nitrogen protective atmosphere by rotary evaporator at 60°C by vacuum distillation (vacuum degree is 0.05MPa) to obtain a brown solid, which is the metal carbide / silicon carbide (ZrC / SiC) multiphase ceramic organic precursor.

[0081] Example 4:

[0082] A metal carbide / silicon carbide (TiC / SiC) multiphase ceramic organic precursor is prepared by the following steps:

[0083] (1) Evacuate the three-necked flask to 0.08 MPa, introduce argon gas, and then continue to evacuate to 0.08 MPa and introduce argon gas, repeating 5 times; then continue to introduce argon gas into the three-necked flask to achieve an inert gas protective atmosphere.

[0084] (2) Under an argon protective atmosphere, titanium source (titanium chloride) was added to carbon source (methacrylic anhydride), stirred at room temperature for 0.5 h, and then alcohol (anhydrous methanol) was added. The mixture was reacted at 40 °C for 1 h to obtain a reddish-brown transparent solution, i.e., the reaction solution; wherein the molar ratio of titanium source, carbon source and alcohol was 1:2:20.

[0085] (3) Continue to use an argon protective atmosphere to remove the solvent from the reaction solution obtained in step (2) by rotary evaporator under reduced pressure at room temperature (vacuum degree is 0.05MPa), and then dry it in a vacuum drying oven at 60℃ for 3h to obtain a brown solid, which is the metal carbide precursor (TiC precursor).

[0086] (4) Continue to add the metal carbide precursor (TiC precursor) obtained in step (3) and liquid hyperbranched polycarbosilane (propynyl polycarbosilane) to the co-solvent (a mixture of anhydrous butanol and anhydrous butanone) under an argon protective atmosphere, and stir at room temperature for 0.8 h to obtain a brownish solution, i.e., the reaction solution; wherein, the mass ratio of metal carbide precursor, liquid hyperbranched polycarbosilane and co-solvent is 1:1:3;

[0087] (5) Continue to remove the solvent from the reaction solution obtained in step (4) under a protective atmosphere of argon by rotary evaporator at 80°C by vacuum distillation (vacuum degree of 0.05MPa) to obtain a brown solid, which is the metal carbide / silicon carbide (TiC / SiC) multiphase ceramic organic precursor.

[0088] Example 5:

[0089] A metal carbide / silicon carbide (TaC / SiC) multiphase ceramic organic precursor is prepared by the following steps:

[0090] (1) Evacuate the three-necked flask to 0.05 MPa, introduce argon gas, and then continue to evacuate to 0.05 MPa and introduce argon gas, repeating 3 times; then continue to introduce argon gas into the three-necked flask to achieve an inert gas protective atmosphere.

[0091] (2) In an argon protective atmosphere, tantalum source (tantalum oxychloride) was added to carbon source (methacrylic anhydride), stirred at room temperature for 0.5 h, and then alcohol (anhydrous methanol) was added. The mixture was reacted at 40 °C for 2 h to obtain a yellowish-brown transparent solution, i.e., the reaction solution; wherein the molar ratio of tantalum source, carbon source and alcohol was 1:2:20.

[0092] (3) Continue to use an argon protective atmosphere to remove the solvent from the reaction solution obtained in step (2) by rotary evaporator under reduced pressure at room temperature (vacuum degree is 0.05MPa), and then dry it in a vacuum drying oven at 60℃ for 12h to obtain a light yellow solid, which is the metal carbide precursor (TaC precursor).

[0093] (4) Continue to add the metal carbide precursor (TaC precursor) obtained in step (3) and liquid hyperbranched polycarbosilane (vinyl polycarbosilane) to the co-solvent (a mixture of anhydrous methanol and anhydrous dichloroethane) under an argon protective atmosphere, and stir at room temperature for 1 h to obtain a brown solution, i.e., the reaction solution; wherein the mass ratio of the metal carbide precursor, liquid hyperbranched polycarbosilane and co-solvent is 1:5:5;

[0094] (5) Continue to remove the solvent from the reaction solution obtained in step (4) under a protective atmosphere of argon by rotary evaporator at room temperature by vacuum distillation (vacuum degree of 0.05MPa) to obtain a brown solid, which is the metal carbide / silicon carbide (TaC / SiC) multiphase ceramic organic precursor.

[0095] Example 6:

[0096] A metal carbide / silicon carbide (NbC / SiC) multiphase ceramic organic precursor is prepared by the following steps:

[0097] (1) Evacuate the three-necked flask to 0.12 MPa, introduce nitrogen gas, then continue to evacuate to 0.05 MPa and introduce nitrogen gas, repeat 6 times; then continue to introduce nitrogen gas into the three-necked flask to achieve an inert gas protective atmosphere.

[0098] (2) In a nitrogen protective atmosphere, niobium source (niobium oxychloride) was added to carbon source (acrylic anhydride), stirred at room temperature for 2 h, and then alcohol (anhydrous butanol) was added. The reaction was carried out at 100 °C for 1 h to obtain a reddish-brown transparent solution, i.e., the reaction solution; wherein the molar ratio of niobium source, carbon source and alcohol is 1:4:5.

[0099] (3) Continue to use a nitrogen protective atmosphere to remove the solvent from the reaction solution obtained in step (2) by rotary evaporator at 80°C by vacuum distillation (vacuum degree is 0.05MPa), and then dry it in a vacuum drying oven at 80°C for 3h to obtain a brown solid, which is the metal carbide precursor (NbC precursor).

[0100] (4) Continue to add the metal carbide precursor (NbC precursor) obtained in step (3) and liquid hyperbranched polycarbosilane (allyl polycarbosilane) to the co-solvent (a mixture of anhydrous ethanol and anhydrous dichloromethane) under a nitrogen protective atmosphere, and stir at room temperature for 0.5 h to obtain a brownish-brown solution, i.e., the reaction solution; wherein the mass ratio of the metal carbide precursor, liquid hyperbranched polycarbosilane and co-solvent is 1:9:10;

[0101] (5) Continue to remove the solvent from the reaction solution obtained in step (4) under a nitrogen protective atmosphere by rotary evaporator at room temperature by vacuum distillation (vacuum degree of 0.05MPa) to obtain a brown solid, which is the metal carbide / silicon carbide (NbC / SiC) multiphase ceramic organic precursor.

[0102] Example 7:

[0103] A metal carbide / silicon carbide (ZrC / SiC) multiphase ceramic organic precursor is prepared by the following steps:

[0104] (1) Evacuate the three-necked flask to 0.08 MPa, introduce nitrogen gas, and then continue to evacuate to 0.08 MPa and introduce nitrogen gas, repeating 4 times; then continue to introduce nitrogen gas into the three-necked flask to achieve an inert gas protective atmosphere.

[0105] (2) Under a nitrogen protective atmosphere, zirconium source (zirconium oxychloride) was added to carbon source (methacrylic anhydride), stirred at room temperature for 1.5 h, and then alcohol (anhydrous propanol) was added. The reaction was carried out at 80 °C for 1.5 h to obtain a brown transparent solution, i.e., the reaction solution; wherein the molar ratio of zirconium source, carbon source and alcohol is 1:3:15.

[0106] (3) Continue to use a nitrogen protective atmosphere to remove the solvent from the reaction solution obtained in step (2) by rotary evaporator at 60°C by vacuum distillation (vacuum degree is 0.05MPa), and then dry it in a vacuum drying oven at 60°C for 3h to obtain a light yellow solid, which is the metal carbide precursor (ZrC precursor).

[0107] (4) Continue to add the metal carbide precursor (ZrC precursor) obtained in step (3) and liquid hyperbranched polycarbosilane (ethynyl polycarbosilane) to the co-solvent (a mixture of anhydrous propanol and anhydrous trichloroethane) under an argon protective atmosphere, and stir at room temperature for 1 hour to obtain a brown solution, i.e., the reaction solution; wherein, the mass ratio of metal carbide precursor, liquid hyperbranched polycarbosilane and co-solvent is 9:1:10;

[0108] (5) Continue to remove the solvent from the reaction solution obtained in step (4) under a nitrogen protective atmosphere by rotary evaporator at 60°C by vacuum distillation (vacuum degree is 0.05MPa) to obtain a brown solid, which is the metal carbide / silicon carbide (ZrC / SiC) multiphase ceramic organic precursor.

[0109] Example 8:

[0110] A metal carbide / silicon carbide (TiC / SiC) multiphase ceramic organic precursor is prepared by the following steps:

[0111] (1) Evacuate the three-necked flask to 0.08 MPa, introduce argon gas, and then continue to evacuate to 0.08 MPa and introduce argon gas, repeating 5 times; then continue to introduce argon gas into the three-necked flask to achieve an inert gas protective atmosphere.

[0112] (2) Under an argon protective atmosphere, titanium source (titanium oxychloride) was added to carbon source (acrylic anhydride), stirred at room temperature for 0.5 h, and then alcohol (anhydrous methanol) was added. The mixture was reacted at 40 °C for 1 h to obtain a reddish-brown transparent solution, i.e., the reaction solution; wherein the molar ratio of titanium source, carbon source and alcohol was 1:2:20.

[0113] (3) Continue to use an argon protective atmosphere to remove the solvent from the reaction solution obtained in step (2) by rotary evaporator under reduced pressure at room temperature (vacuum degree is 0.05MPa), and then dry it in a vacuum drying oven at 60℃ for 3h to obtain a brown solid, which is the metal carbide precursor (TiC precursor).

[0114] (4) Continue to add the metal carbide precursor (TiC precursor) obtained in step (3) and liquid hyperbranched polycarbosilane (propynyl polycarbosilane) to the co-solvent (a mixture of anhydrous butanol and anhydrous toluene) under an argon protective atmosphere, and stir at room temperature for 1 h to obtain a brown solution, i.e., the reaction solution; wherein, the mass ratio of metal carbide precursor, liquid hyperbranched polycarbosilane and co-solvent is 5:1:3;

[0115] (5) Continue to remove the solvent from the reaction solution obtained in step (4) under a protective atmosphere of argon by rotary evaporator at 80°C by vacuum distillation (vacuum degree of 0.05MPa) to obtain a brown solid, which is the metal carbide / silicon carbide (TiC / SiC) multiphase ceramic organic precursor.

[0116] Examples 9-15:

[0117] A metal carbide / silicon carbide (TaC / SiC) multiphase ceramic organic precursor is prepared by the following steps:

[0118] In step (2), the tantalum source is tantalum pentaethanol, tantalum pentaethanol, tantalum pentapropoxide, tantalum pentaisopropoxide, tantalum pentabutoxide, tantalum pentaisobutoxide or tantalum penpentyl alcohol, and the rest is the same as in Example 1.

[0119] Examples 16-22:

[0120] A metal carbide / silicon carbide (NbC / SiC) multiphase ceramic organic precursor is prepared by the following steps:

[0121] In step (2), the niobium source is niobium pentamethanol, niobium pentamethanol, niobium pentampropoxide, niobium pentamisopropoxide, niobium pentambutoxide, niobium pentamisobutoxide or niobium pentampentoxide, and the rest is the same as in Example 2.

[0122] Examples 23-29:

[0123] A metal carbide / silicon carbide (ZrC / SiC) multiphase ceramic organic precursor is prepared by the following steps:

[0124] In step (2), the zirconium source is zirconium tetraethanol, zirconium tetraethanol, zirconium tetrapropoxide, zirconium tetraisopropoxide, zirconium tetrabutoxide, zirconium tetraisobutoxide or zirconium tetrapentoxide, and the rest is the same as in Example 3.

[0125] Examples 30-36:

[0126] A metal carbide / silicon carbide (TiC / SiC) multiphase ceramic organic precursor is prepared by the following steps:

[0127] In step (2), the titanium source is titanium tetramethanol, titanium tetraethanol, titanium tetrapropoxide, titanium tetraisopropoxide, titanium tetrabutoxide, titanium tetraisobutoxide, or titanium tetrapentoxide, and the rest is the same as in Example 4.

[0128] Test case

[0129] I. The metal carbide / silicon carbide multiphase ceramic organic precursors prepared in Examples 1-4 were subjected to FT-IR infrared spectroscopy, and the results are shown in the figure. Figure 1-4 .

[0130] Depend on Figure 1-4 It is known that the metal carbide / silicon carbide multiphase ceramic organic precursor contains major structural units such as C=C, C=O, CO, OH, MCO (M=Ta, Nb, Zr, Ti), MO (M=Ta, Nb, Zr, Ti), Si-H, and Si-CH3.

[0131] II. Thermogravimetric analysis was performed on the metal carbide / silicon carbide multiphase ceramic organic precursors prepared in Examples 1-4, and the results are shown below. Figure 5-8 (The horizontal axis represents temperature (°C), and the vertical axis represents ceramic yield (%)).

[0132] Depend on Figure 5-8 It is known that the ceramic yield of the metal carbide / silicon carbide multiphase ceramic organic precursor is as high as 50% or more at 1500℃.

[0133] III. The metal carbide / silicon carbide multiphase ceramic organic precursors prepared in Examples 1-4 were pyrolyzed at 1500℃, and the products were subjected to X-ray diffraction. The results are shown in the figure. Figure 9-12 .

[0134] Depend on Figure 9-12 It can be seen that the phase composition of the ceramic product prepared by pyrolysis at 1500℃ is metal carbide and silicon carbide, and no characteristic peaks of oxides are observed, indicating that the organic precursor of the multiphase ceramic prepared in this invention is completely transformed into metal carbide / silicon carbide multiphase ceramic at 1500℃.

[0135] IV. The metal carbide / silicon carbide multiphase ceramic organic precursors prepared in Examples 1-4 were pyrolyzed at 1500℃, and the products were examined by high-magnification transmission electron microscopy. The results are shown in the figure. Figure 13-16 .

[0136] Depend on Figure 13-16 As can be seen, the transmission electron microscopy results further confirmed that the pyrolysis products of the multiphase ceramic organic precursor prepared in this invention at 1500℃ are metal carbide / silicon carbide multiphase ceramics.

[0137] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a metal carbide / silicon carbide multiphase ceramic organic precursor, characterized in that, Includes the following steps: (1) Under an inert atmosphere, the metal carbide precursor and liquid hyperbranched polycarbosilane are added to a co-solvent and stirred at room temperature for 0.5-1 h to obtain a reaction solution; (2) Continue to remove the solvent from the reaction solution obtained in step (1) under the inert atmosphere described in step (1) by vacuum distillation to obtain a solid, which is the metal carbide / silicon carbide multiphase ceramic organic precursor; In step (1), the metal carbide precursor is a tantalum carbide precursor, a niobium carbide precursor, a zirconium carbide precursor, or a titanium carbide precursor; Metal carbide precursors are prepared by the following method: S1: In an inert gas protective atmosphere, add the metal source to the carbon source, stir at room temperature for 0.5-2h, then add alcohol, and react at 40-100℃ for 1-2h to obtain a reaction solution; wherein, the molar ratio of metal source, carbon source and alcohol is 1:2-4:5-20. S2: Continue in the inert gas protective atmosphere described in step S1 to remove the solvent from the reaction solution prepared in step S1, and then vacuum dry it at 60-80℃ for 3-12h to obtain a solid, which is the metal carbide organic precursor. In step S1, the carbon source is methacrylic anhydride or acrylic anhydride; In step (1), the liquid hyperbranched polycarbosilane is a liquid hyperbranched polycarbosilane containing carbon-carbon unsaturated bonds; The liquid hyperbranched polycarbosilane is vinyl polycarbosilane, allyl polycarbosilane, ethynyl polycarbosilane, or propargyl polycarbosilane; In step (2), the sample is distilled under reduced pressure at room temperature to 80°C.

2. The method for preparing the metal carbide / silicon carbide multiphase ceramic organic precursor according to claim 1, characterized in that, In step (1), the inert atmosphere is nitrogen or argon.

3. The method for preparing the metal carbide / silicon carbide multiphase ceramic organic precursor according to claim 1, characterized in that, In step (1), the mass ratio of the metal carbide precursor, the liquid hyperbranched polycarbosilane and the co-solvent is 1-9:1-9:3-10.

4. The method for preparing the metal carbide / silicon carbide multiphase ceramic organic precursor according to claim 1, characterized in that, In step (1), the co-solvent is a mixture of solvent one and solvent two. Solvent one is methanol, ethanol, propanol or butanol, and solvent two is tetrahydrofuran, acetone, toluene, butanone, dichloroethane, dichloromethane or trichloromethane.

5. The metal carbide / silicon carbide multiphase ceramic organic precursor prepared by the method of any one of claims 1-4.

6. The application of the metal carbide / silicon carbide multiphase ceramic organic precursor of claim 5 in the preparation of metal carbide / silicon carbide multiphase ceramics.

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