A tungsten wire toughened silicon carbide ceramic matrix composite material and a method of making the same

Abstract

The application belongs to the technical field of silicon carbide ceramic matrix composites, and particularly relates to a tungsten wire toughened silicon carbide ceramic matrix composite and a preparation method thereof. The preparation method comprises the following steps: S1, weaving tungsten wires into a first tungsten wire preform; S2, performing chemical vapor deposition on the first tungsten wire preform by using a process gas to obtain a second tungsten wire preform, and a silicon carbide coating is formed on the surface of the second tungsten wire preform; S3, impregnating the second tungsten wire preform with a silicon carbide slurry and sintering to obtain a third tungsten wire preform, and the third tungsten wire preform is filled with a silicon carbide matrix; and S4, repeating step S3 to obtain the tungsten wire toughened silicon carbide ceramic matrix composite. The tungsten wire is used as a toughening phase of the silicon carbide ceramic composite, and the preparation process of the silicon carbide ceramic matrix composite is optimized, so that the mechanical properties of the silicon carbide ceramic composite can be significantly improved.

Description

Technical Field

[0001] The present application relates to the technical field of silicon carbide ceramic-based composite materials. Specifically, the present application relates to a tungsten filament toughened silicon carbide ceramic-based composite material and a preparation method thereof. Background Art

[0002] Silicon carbide ceramics offer advantages such as low density, high hardness, high stiffness, wear resistance, oxidation resistance, thermal shock resistance, high thermal conductivity, low expansion coefficient, and low neutron absorption cross-section. They are widely used in precision bearings, compression cylinders, wear-resistant seals, gas rotors, and nuclear reactors. However, because silicon carbide is a brittle ceramic material, cracks inevitably cause catastrophic failure, making it crucial to improve its fracture toughness.

[0003] There are several methods to improve the fracture toughness of silicon carbide ceramics: particle toughening, pore toughening, whisker toughening and continuous fiber toughening. Toughening methods such as particle toughening, pore toughening and whisker toughening can cause cracks inside silicon carbide ceramics to deflect and bifurcate during diffusion, which can improve its fracture toughness to a certain extent, but the degree of improvement in fracture toughness is limited. Continuous fiber toughened silicon carbide ceramic-based composites have good toughening effects and mature preparation technology. The invention patent with announcement number CN102249721B discloses a method for carbon fiber reinforced silicon carbide, which adopts the method of precursor impregnation and high-temperature pyrolysis to prepare carbon fiber reinforced silicon carbide composite materials. The invention patent with announcement number CN102276279B discloses a method for silicon carbide fiber reinforced silicon carbide, which adopts the method of precursor impregnation, hot molding and high-temperature pyrolysis to prepare silicon carbide fiber reinforced silicon carbide composite materials. The above patents all effectively improve the fracture toughness of silicon carbide ceramics.

[0004] Tungsten wire has excellent mechanical properties, high temperature resistance, and a thermal expansion coefficient that matches well with silicon carbide (the thermal expansion coefficient of tungsten wire is 4.5×10 -6 / K, the thermal expansion coefficient of silicon carbide is 4.0-4.5×10 -6 / K) and other advantages. Therefore, there is an urgent need for a preparation method that can utilize the excellent properties of tungsten wire and apply it to silicon carbide ceramic-based composites. Summary of the Invention

[0005] In order to solve the above technical problems, the present application provides a preparation method of a tungsten wire toughened silicon carbide ceramic-based composite material, which is characterized in that it includes the following steps: S1, weaving tungsten wire into a first tungsten wire preform; S2, using process gas to perform chemical vapor deposition on the first tungsten wire preform to obtain a second tungsten wire preform, and a silicon carbide coating is formed on the surface of the second tungsten wire preform; S3, using silicon carbide slurry to impregnate the second tungsten wire preform and sintering to obtain a third tungsten wire preform, and the third tungsten wire preform is filled with a silicon carbide matrix; S4, repeating step S3 to obtain a tungsten wire toughened silicon carbide ceramic-based composite material.

[0006] As a preferred embodiment of the method for preparing a tungsten wire toughened silicon carbide ceramic matrix composite material described in the present application, in step S1, the specific structure of the first tungsten wire preform includes: a 2.5D structure, a three-dimensional four-directional structure, a three-dimensional five-directional structure or a three-dimensional six-directional structure.

[0007] As a preferred embodiment of the method for preparing a tungsten filament toughened silicon carbide ceramic matrix composite material described in the present application, in step S2, the process gas includes methylsilane or tetrachloromethylsilane, the temperature of the chemical vapor deposition is 900-1200° C., the pressure of the chemical vapor deposition is 500-9000 Pa, and the thickness of the silicon carbide coating on the surface of the second tungsten filament preform is 50-500 nm;

[0008] Furthermore, the thickness of the silicon carbide coating on the surface of the second tungsten filament preform is any one of 50 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, or a range between two of them.

[0009] As a preferred embodiment of the method for preparing a tungsten filament toughened silicon carbide ceramic-based composite material described in the present application, in step S3, the silicon carbide slurry is composed of silicon carbide powder, solvent, dispersant, and defoaming agent, and the content of solid matter in the silicon carbide slurry is 15wt%-60wt%.

[0010] As a preferred embodiment of the method for preparing a tungsten wire-toughened silicon carbide ceramic-based composite material described in the present application, the particle size of the silicon carbide powder is 50 nm-10 μm; the solvent includes liquid polycarbosilane; the dispersant includes sodium polyacrylate or polycarboxylate; and the defoamer includes a polyether defoamer or a polyoxyethylene-polyoxypropylene block copolymer defoamer.

[0011] As a preferred embodiment of the method for preparing a tungsten filament toughened silicon carbide ceramic-based composite material described in the present application, the mass ratio of the solvent, the dispersant, and the defoaming agent is (81.9-94.4): (15.6-5.5): (2.5-0.1).

[0012] As a preferred embodiment of the method for preparing a tungsten wire-toughened silicon carbide ceramic-based composite material described in the present application, in step S3, the immersion pressure is less than 20 Pa, and the immersion time is 5-50 hours.

[0013] As a preferred embodiment of the method for preparing a tungsten wire-toughened silicon carbide ceramic-based composite material described in the present application, in step S3, the sintering temperature is 900-1400°C, the sintering time is 1-3 hours, and the sintering is carried out in a vacuum, nitrogen or argon environment.

[0014] As a preferred embodiment of the method for preparing a tungsten wire toughened silicon carbide ceramic matrix composite material described in the present application, in step S4, step S3 is repeated 6-13 times.

[0015] The present application also provides a tungsten wire toughened silicon carbide ceramic matrix composite material, which is prepared using the above-mentioned preparation method of the tungsten wire toughened silicon carbide ceramic matrix composite material. The density of the tungsten wire toughened silicon carbide ceramic matrix composite material is greater than or equal to 95%, the compressive strength of the tungsten wire toughened silicon carbide ceramic matrix composite material is greater than or equal to 680 MPa, the flexural strength of the tungsten wire toughened silicon carbide ceramic matrix composite material is greater than or equal to 825 MPa, the tensile strength of the tungsten wire toughened silicon carbide ceramic matrix composite material is greater than or equal to 595 MPa, and the fracture toughness of the tungsten wire toughened silicon carbide ceramic matrix composite material is greater than or equal to 25 MPa·m 1 / 2 , the volume fraction of the tungsten wire is 40%-65%.

[0016] The beneficial effects of this application are as follows:

[0017] The present application provides a method for preparing a tungsten filament toughened silicon carbide ceramic matrix composite material, which uses tungsten filament as the toughening phase of the silicon carbide ceramic composite material and optimizes the preparation process of the silicon carbide ceramic matrix composite material to significantly improve the mechanical properties of the silicon carbide ceramic composite material;

[0018] The present application also provides a tungsten wire toughened silicon carbide ceramic matrix composite material, which uses tungsten wire as the toughening phase of the silicon carbide ceramic composite material and has excellent mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0020] Figure 1 A schematic diagram of the preparation process of the tungsten wire toughened silicon carbide ceramic matrix composite material in the present application is shown in the figure.

[0021] Figure 2 A photo of the tungsten wire toughened silicon carbide ceramic matrix composite material prepared in Example 1 in the present application is shown in the figure.

[0022] The implementation, functional features and advantages of the present application will be further described with reference to the accompanying drawings. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments will be described below in a clear and complete manner. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0024] The present application provides a preparation method of a tungsten wire toughened silicon carbide ceramic matrix composite material, characterized by comprising the following steps: S1, weaving tungsten wires into a first tungsten wire preform; S2, performing chemical vapor deposition on the first tungsten wire preform by using a process gas to obtain a second tungsten wire preform, and a silicon carbide coating is formed on the surface of the second tungsten wire preform; S3, impregnating and sintering the second tungsten wire preform by using a silicon carbide slurry to obtain a third tungsten wire preform, and the third tungsten wire preform is filled with a silicon carbide matrix; S4, repeating the step S3 to obtain a tungsten wire toughened silicon carbide ceramic matrix composite material.

[0025] As a preferred scheme of the preparation method of the tungsten wire toughened silicon carbide ceramic matrix composite material, in the step S1, the specific structure of the first tungsten wire preform comprises a 2.5D structure, a three-dimensional four-way structure, a three-dimensional five-way structure or a three-dimensional six-way structure.

[0026] As a preferred scheme of the preparation method of the tungsten wire toughened silicon carbide ceramic matrix composite material, in the step S2, the process gas comprises methylsilane or tetrachloromethylsilane, the temperature of the chemical vapor deposition is 900-1200℃, the pressure of the chemical vapor deposition is 500-9000Pa, and the thickness of the silicon carbide coating on the surface of the second tungsten wire preform is 50-500nm.

[0027] As a preferred scheme of the preparation method of the tungsten wire toughened silicon carbide ceramic matrix composite material, in the step S3, the silicon carbide slurry is composed of silicon carbide powder, a solvent, a dispersing agent and a defoaming agent, and the content of the solid substances in the silicon carbide slurry is 15wt%-60wt%.

[0028] As a preferred scheme of the preparation method of the tungsten wire toughened silicon carbide ceramic matrix composite material, the particle size of the silicon carbide powder is 50 nm-10 μm; the solvent comprises liquid polycarbosilane; the dispersing agent comprises sodium polyacrylate or polycarboxylate; and the defoaming agent comprises polyether type defoaming agent or polyoxyethylene-polyoxypropylene block copolymer defoaming agent.

[0029] As a preferred scheme of the preparation method of the tungsten wire toughened silicon carbide ceramic matrix composite material, the mass ratio of the solvent, the dispersing agent and the defoaming agent is (81.9-94.4):(15.6-5.5):(2.5-0.1).

[0030] As a preferred scheme of the preparation method of the tungsten wire toughened silicon carbide ceramic matrix composite material, in the step S3, the pressure of the impregnation is less than 20 Pa, and the time of the impregnation is 5-50 h.

[0031] As a preferred scheme of the preparation method of the tungsten wire toughened silicon carbide ceramic matrix composite material, in the step S3, the temperature of the sintering is 900-1400 ℃, the time of the sintering is 1-3 h, and the sintering is carried out in a vacuum, nitrogen or argon environment.

[0032] As a preferred scheme of the preparation method of the tungsten wire toughened silicon carbide ceramic matrix composite material, in the step S4, the step S3 is repeated for 6-13 times.

[0033] The application further provides a tungsten wire toughened silicon carbide ceramic matrix composite material, which is prepared by the above preparation method of the tungsten wire toughened silicon carbide ceramic matrix composite material, and has a density of greater than or equal to 95%, a compressive strength of greater than or equal to 680 MPa, a bending strength of greater than or equal to 825 MPa, a tensile strength of greater than or equal to 595 MPa, and a fracture toughness of greater than or equal to 25 MPa·m 1 / 2 The volume fraction of the tungsten wire is 40%-65%.

[0034] The technical scheme of the application is further described below with reference to specific embodiments.

[0035] Please refer to Figure 1 , Figure 1This is a schematic diagram of the preparation process of the tungsten filament toughened silicon carbide ceramic-based composite material of the present application. Tungsten filaments are braided to obtain a first tungsten filament preform, the first tungsten filament preform is subjected to chemical vapor deposition to obtain a second tungsten filament preform, the second tungsten filament preform is impregnated with silicon carbide slurry and sintered to obtain a third tungsten filament preform, and the steps of impregnating and sintering the third tungsten filament preform are repeated to obtain a tungsten filament toughened silicon carbide ceramic-based composite material.

[0036] Example 1

[0037] A tungsten filament toughened silicon carbide ceramic matrix composite material and a preparation method thereof, wherein the specific preparation method comprises the following steps:

[0038] Step S1: weaving tungsten wires into a first tungsten wire preform, wherein the structure of the first tungsten wire preform is a 2.5D structure;

[0039] Step S2: chemical vapor deposition is performed on the first tungsten filament preform using a process gas to obtain a second tungsten filament preform, wherein a silicon carbide coating is formed on the surface of the second tungsten filament preform, wherein: the process gas is methylsilane, the chemical vapor deposition temperature is 900° C., the pressure is 500 Pa, and the thickness of the silicon carbide coating on the second tungsten filament preform is 50 nm;

[0040] Step S3: Adding silicon carbide powder, a dispersant, and a defoamer to a solvent to prepare a silicon carbide slurry, wherein: the particle size of the silicon carbide powder is 50 nm, the dispersant is sodium polyacrylate, the defoamer is a polyether defoamer, the solvent is liquid polycarbosilane, the solid matter content in the silicon carbide slurry is 41 wt %; and the mass ratio of the solvent, the dispersant, and the defoamer is 81.9:15.6:2.5;

[0041] Step S4: impregnating the second tungsten filament preform in step S2 with the silicon carbide slurry in step S3 and sintering to obtain a third tungsten filament preform, wherein the third tungsten filament preform is filled with a silicon carbide matrix, wherein: the impregnation pressure is 10 Pa, the impregnation time is 5 hours, the sintering temperature is 900° C., the sintering time is 1 hour, and the sintering is performed in a vacuum environment;

[0042] Step S5: Repeat step S4 six times to obtain a tungsten wire toughened silicon carbide ceramic matrix composite material.

[0043] The properties of the tungsten wire toughened silicon carbide ceramic matrix composite material prepared in Example 1 are as follows: density of 95.32%, compressive strength of 689.63 MPa, flexural strength of 834.51 MPa, tensile strength of 601.79 MPa, fracture toughness of 28.43 MPa·m 1 / 2 , where the volume fraction of tungsten wire is 41%.

[0044] See alsoFigure 2 , Figure 2 This is a photo of the tungsten wire toughened silicon carbide ceramic matrix composite material prepared in Example 1 of this application.

[0045] Example 2

[0046] A tungsten filament toughened silicon carbide ceramic matrix composite material and a preparation method thereof, wherein the specific preparation method comprises the following steps:

[0047] Step S1: weaving tungsten wires into a first tungsten wire preform, wherein the structure of the first tungsten wire preform is a three-dimensional four-directional structure;

[0048] Step S2: chemical vapor deposition is performed on the first tungsten filament preform using a process gas to obtain a second tungsten filament preform, wherein a silicon carbide coating is formed on the surface of the second tungsten filament preform, wherein: the process gas is tetrachloromethylsilane, the chemical vapor deposition temperature is 1200° C., the pressure is 9000 Pa, and the thickness of the silicon carbide coating on the second tungsten filament preform is 500 nm;

[0049] Step S3: Adding silicon carbide powder, a dispersant, and a defoamer to a solvent to prepare a silicon carbide slurry, wherein: the particle size of the silicon carbide powder is 900 nm, the dispersant is sodium polyacrylate, the defoamer is a polyoxyethylene-polyoxypropylene segmented copolymer defoamer, the solvent is liquid polycarbosilane, the solid matter content in the silicon carbide slurry is 15 wt %; and the mass ratio of the solvent, dispersant, and defoamer is 89.6:8.7:1.7;

[0050] Step S4: impregnating the second tungsten filament preform in step S2 with the silicon carbide slurry in step S3 and sintering to obtain a third tungsten filament preform, wherein the third tungsten filament preform is filled with a silicon carbide matrix, wherein: the impregnation pressure is 5 Pa, the impregnation time is 50 h, the sintering temperature is 1400° C., the sintering time is 2 h, and the sintering is performed in a nitrogen environment;

[0051] Step S5: Repeat step S4 9 times to obtain a tungsten wire toughened silicon carbide ceramic matrix composite material.

[0052] The properties of the tungsten wire toughened silicon carbide ceramic matrix composite material prepared in Example 2 are as follows: density of 96.43%, compressive strength of 712.56 MPa, flexural strength of 903.42 MPa, tensile strength of 789.54 MPa, fracture toughness of 35.41 MPa·m 1 / 2 , of which the volume fraction of tungsten wire is 53%.

[0053] Example 3

[0054] A tungsten filament toughened silicon carbide ceramic matrix composite material and a preparation method thereof, wherein the specific preparation method comprises the following steps:

[0055] Step S1: a tungsten wire is braided into a first tungsten wire preform, wherein: the structure of the first tungsten wire preform is a three-dimensional five-directional structure;

[0056] Step S2: a second tungsten wire preform is obtained by chemical vapor deposition on the first tungsten wire preform using a process gas, and a silicon carbide coating is formed on the surface of the second tungsten wire preform, wherein: the process gas is methylsilane, the temperature of the chemical vapor deposition is 1100℃, the pressure is 6000Pa, and the thickness of the silicon carbide coating of the second tungsten wire preform is 370nm;

[0057] Step S3: silicon carbide powder, a dispersing agent and a defoaming agent are added to a solvent to prepare a silicon carbide slurry, wherein: the particle size of the silicon carbide powder is 10μm, the dispersing agent is a polycarboxylate, the defoaming agent is a polyether type defoaming agent, the solvent is liquid polycarbosilane, and the content of solid substances in the silicon carbide slurry is 60wt%; the mass ratio of the solvent, the dispersing agent and the defoaming agent is 94.4:5.5:0.1;

[0058] Step S4: the second tungsten wire preform in step S2 is impregnated with the silicon carbide slurry in step S3 and sintered to obtain a third tungsten wire preform filled with a silicon carbide matrix, wherein: the pressure of the impregnation is 8Pa, the time of the impregnation is 30h, the temperature of the sintering is 1200℃, the time of the sintering is 3h, and the sintering is carried out in an argon environment;

[0059] Step S5: the step S4 is repeated 13 times to obtain a tungsten wire toughened silicon carbide ceramic matrix composite material.

[0060] The properties of the tungsten wire toughened silicon carbide ceramic matrix composite material prepared in Example 3 are as follows: the density is 98.21%, the compressive strength is 733.97MPa, the bending strength is 878.46MPa, the tensile strength is 803.65MPa, and the fracture toughness is 40.19MPa·m 1 / 2 , wherein the volume fraction of the tungsten wire is 65%.

[0061] Example 4

[0062] A tungsten wire toughened silicon carbide ceramic matrix composite material and a preparation method thereof, the steps of the specific preparation method are as follows:

[0063] Step S1: a tungsten wire is braided into a first tungsten wire preform, wherein: the structure of the first tungsten wire preform is a three-dimensional five-directional structure;

[0064] Step S2: chemical vapor deposition is performed on the first tungsten filament preform using a process gas to obtain a second tungsten filament preform, wherein a silicon carbide coating is formed on the surface of the second tungsten filament preform, wherein: the process gas is tetrachloromethylsilane, the chemical vapor deposition temperature is 1150° C., the pressure is 2000 Pa, and the thickness of the silicon carbide coating on the second tungsten filament preform is 200 nm;

[0065] Step S3: Adding silicon carbide powder, a dispersant, and a defoamer to a solvent to prepare a silicon carbide slurry, wherein: the particle size of the silicon carbide powder is 4 μm, the dispersant is a polycarboxylate, the defoamer is a polyoxyethylene-polyoxypropylene segmented copolymer defoamer, the solvent is liquid polycarbosilane, the solid matter content in the silicon carbide slurry is 29 wt %; and the mass ratio of the solvent, dispersant, and defoamer is 87.5:11.6:0.9;

[0066] Step S4: impregnating the second tungsten filament preform in step S2 with the silicon carbide slurry in step S3 and sintering to obtain a third tungsten filament preform, wherein the third tungsten filament preform is filled with a silicon carbide matrix, wherein: the impregnation pressure is 19 Pa, the impregnation time is 24 hours, the sintering temperature is 1300° C., the sintering time is 2.5 hours, and the sintering is performed in a nitrogen environment;

[0067] Step S5: Repeat step S4 11 times to obtain a tungsten wire toughened silicon carbide ceramic matrix composite material.

[0068] The properties of the tungsten wire toughened silicon carbide ceramic matrix composite material prepared in Example 4 are as follows: density of 97.21%, compressive strength of 696.78 MPa, flexural strength of 921.37 MPa, tensile strength of 776.33 MPa, fracture toughness of 37.96 MPa·m 1 / 2 , of which the volume fraction of tungsten wire is 58%.

[0069] Comparative Example 1

[0070] A tungsten filament toughened silicon carbide ceramic matrix composite material and a preparation method thereof, wherein the specific preparation method comprises the following steps:

[0071] Step S1: weaving tungsten wires into a first tungsten wire preform, wherein the structure of the first tungsten wire preform is a three-dimensional six-directional structure;

[0072] Step S2: chemical vapor deposition is performed on the first tungsten filament preform using a process gas to obtain a second tungsten filament preform, wherein a silicon carbide coating is formed on the surface of the second tungsten filament preform, wherein: the process gas is tetrachloromethylsilane, the chemical vapor deposition temperature is 1150° C., the pressure is 2000 Pa, and the thickness of the silicon carbide coating on the second tungsten filament preform is 200 nm;

[0073] Step S3: adding silicon carbide powder to a solvent to prepare a silicon carbide slurry, wherein: the particle size of the silicon carbide powder is 4 μm, the solvent is liquid polycarbosilane, and the solid content in the silicon carbide slurry is 29 wt%;

[0074] Step S4: impregnating the second tungsten filament preform in step S2 with the silicon carbide slurry in step S3 and sintering to obtain a third tungsten filament preform, wherein the third tungsten filament preform is filled with a silicon carbide matrix, wherein: the impregnation pressure is 19 Pa, the impregnation time is 24 hours, the sintering temperature is 1300° C., the sintering time is 2.5 hours, and the sintering is performed in a nitrogen environment;

[0075] Step S5: Repeat step S4 11 times to obtain a tungsten wire toughened silicon carbide ceramic matrix composite material.

[0076] The properties of the tungsten wire toughened silicon carbide ceramic matrix composite material prepared in Comparative Example 1 are as follows: density of 90.56%, compressive strength of 453.44 MPa, flexural strength of 567.31 MPa, tensile strength of 221.49 MPa, fracture toughness of 15.21 MPa·m 1 / 2 , of which the volume fraction of tungsten wire is 58%.

[0077] Comparative Example 2

[0078] A tungsten filament toughened silicon carbide ceramic matrix composite material and a preparation method thereof, wherein the specific preparation method comprises the following steps:

[0079] Step S1: weaving tungsten wires into a first tungsten wire preform, wherein the structure of the first tungsten wire preform is a three-dimensional six-directional structure;

[0080] Step S2: Adding silicon carbide powder, a dispersant, and a defoamer to a solvent to prepare a silicon carbide slurry, wherein: the particle size of the silicon carbide powder is 4 μm, the dispersant is a polycarboxylate, the defoamer is a polyoxyethylene-polyoxypropylene segmented copolymer defoamer, the solvent is liquid polycarbosilane, the solid matter content in the silicon carbide slurry is 29 wt %; and the mass ratio of the solvent, dispersant, and defoamer is 87.5:11.6:0.9;

[0081] Step S3: impregnating the second tungsten filament preform in step S1 with the silicon carbide slurry in step S2 and sintering to obtain a third tungsten filament preform, wherein the third tungsten filament preform is filled with a silicon carbide matrix, wherein: the impregnation pressure is 19 Pa, the impregnation time is 24 hours, the sintering temperature is 1300° C., the sintering time is 2.5 hours, and the sintering is performed in a nitrogen environment;

[0082] Step S4: repeat step S3 11 times to obtain a tungsten wire toughened silicon carbide ceramic matrix composite material.

[0083] The properties of the tungsten wire toughened silicon carbide ceramic matrix composite material prepared in Comparative Example 2 are as follows: density of 96.30%, compressive strength of 489.31 MPa, flexural strength of 498.78 MPa, tensile strength of 289.54 MPa, fracture toughness of 10.34 MPa·m 1 / 2 , of which the volume fraction of tungsten wire is 58%.

[0084] Comparative Example 3

[0085] A tungsten filament toughened silicon carbide ceramic matrix composite material and a preparation method thereof, wherein the specific preparation method comprises the following steps:

[0086] Step S1: weaving tungsten wires into a first tungsten wire preform, wherein the structure of the first tungsten wire preform is a three-dimensional six-directional structure;

[0087] Step S2: chemical vapor deposition is performed on the first tungsten filament preform using a process gas to obtain a second tungsten filament preform, wherein a silicon carbide coating is formed on the surface of the second tungsten filament preform, wherein: the process gas is tetrachloromethylsilane, the chemical vapor deposition temperature is 1150° C., the pressure is 2000 Pa, and the thickness of the silicon carbide coating on the second tungsten filament preform is 200 nm;

[0088] Step S3: Adding silicon carbide powder, a dispersant, and a defoamer to a solvent to prepare a silicon carbide slurry, wherein: the particle size of the silicon carbide powder is 4 μm, the dispersant is a polycarboxylate, the defoamer is a polyoxyethylene-polyoxypropylene segmented copolymer defoamer, the solvent is liquid polycarbosilane, the solid matter content in the silicon carbide slurry is 29 wt %; and the mass ratio of the solvent, dispersant, and defoamer is 87.5:11.6:0.9;

[0089] Step S4: impregnating the second tungsten filament preform in step S2 with the silicon carbide slurry in step S3 and sintering to obtain a third tungsten filament preform, wherein the third tungsten filament preform is filled with a silicon carbide matrix, wherein: the impregnation pressure is 50 Pa, the impregnation time is 24 hours, the sintering temperature is 1300° C., the sintering time is 2.5 hours, and the sintering is performed in a nitrogen environment;

[0090] Step S5: Repeat step S4 11 times to obtain a tungsten wire toughened silicon carbide ceramic matrix composite material.

[0091] The properties of the tungsten wire toughened silicon carbide ceramic matrix composite material prepared in Example 4 are as follows: density of 89.53%, compressive strength of 397.72 MPa, flexural strength of 334.55 MPa, tensile strength of 187.35 MPa, fracture toughness of 8.48 MPa·m 1 / 2 , of which the volume fraction of tungsten wire is 58%.

[0092] Comparative Example 4

[0093] A tungsten filament toughened silicon carbide ceramic matrix composite material and a preparation method thereof, wherein the specific preparation method comprises the following steps:

[0094] Step S1: weaving tungsten wires into a first tungsten wire preform, wherein the structure of the first tungsten wire preform is a three-dimensional six-directional structure;

[0095] Step S2: adding silicon carbide powder to a solvent to prepare a silicon carbide slurry, wherein: the particle size of the silicon carbide powder is 4 μm, the solvent is liquid polycarbosilane, and the solid content in the silicon carbide slurry is 29 wt%;

[0096] Step S3: impregnating the second tungsten filament preform in step S1 with the silicon carbide slurry in step S2 and sintering to obtain a third tungsten filament preform, wherein the third tungsten filament preform is filled with a silicon carbide matrix, wherein: the impregnation pressure is 50 Pa, the impregnation time is 24 hours, the sintering temperature is 1300° C., the sintering time is 2.5 hours, and the sintering is performed in a nitrogen environment;

[0097] Step S4: repeat step S3 11 times to obtain a tungsten wire toughened silicon carbide ceramic matrix composite material.

[0098] The properties of the tungsten wire toughened silicon carbide ceramic matrix composite material prepared in Example 4 are as follows: density of 85.63%, compressive strength of 333.18 MPa, flexural strength of 275.28 MPa, tensile strength of 123.91 MPa, fracture toughness of 6.58 MPa·m 1 / 2 , of which the volume fraction of tungsten wire is 58%.

[0099] Comparative Example 5

[0100] Comparative Example 5 refers to a carbon fiber reinforced silicon carbide composite material sample prepared by the process in the invention patent application number 200810030556.X.

[0101] The carbon fiber reinforced silicon carbide composite material prepared in this embodiment has the following properties: compressive strength of 212.34 MPa, flexural strength of 449.76 MPa, tensile strength of 102.81 MPa, and fracture toughness of 10.27 MPa·m 1 / 2 .

[0102] Comparative Example 6

[0103] Comparative Example 6 refers to a carbon fiber reinforced silicon carbide composite material sample prepared by the process in the invention patent application number 201110154829.3.

[0104] The performance of the silicon carbide fiber reinforced silicon carbide composite material prepared in the example is as follows: the compressive strength is 367.59 MPa, the bending strength is 639.68 MPa, the tensile strength is 189.11 MPa, and the fracture toughness is 25.72 MPa·m 1 / 2 .

[0105] It can be seen from the above examples and comparative examples that: Example 4 combined with Comparative Example 1 shows that the presence or absence of the dispersant and the defoaming agent in the silicon carbide slurry in the step S3 will affect the performance of the final sample, and the absence of the dispersant and the defoaming agent will cause uneven distribution of the silicon carbide powder in the silicon carbide slurry, and then the impregnation effect of the silicon carbide powder in the second tungsten wire preform is poor, resulting in a decrease in the performance of the final sample; Example 4 combined with Comparative Example 2 shows that the presence or absence of the chemical vapor deposition step in the step S2 in Example 4 will affect the performance of the final sample, and the absence of the chemical vapor deposition silicon carbide interface coating on the surface of the first tungsten wire preform will cause hard connection between the tungsten wire and the silicon carbide matrix, and then result in a decrease in the performance of the final sample; Example 4 combined with Comparative Example 3 shows that the pressure in the step S4 in Example 4 will affect the performance of the final sample, and the pressure being too high will cause poor impregnation effect and low sample density, and then result in a decrease in the performance of the final sample; Example 4 combined with Comparative Example 4 shows that the dispersant and the defoaming agent, the chemical vapor deposition, and the pressure in the impregnation have a synergistic effect on the performance of the final sample; it can be known from Example 1, Example 2, Example 3, Example 4, Comparative Example 5, and Comparative Example 6 that the mechanical properties of the tungsten wire toughened silicon carbide ceramic matrix composite material are superior to those of the carbon fiber reinforced silicon carbide composite material, the method uses tungsten wire as a toughening phase, and the tungsten wire toughened silicon carbide ceramic matrix composite material prepared by optimizing the preparation process has excellent mechanical properties, and meets the requirements of special service conditions.

[0106] The application provides a preparation method of a tungsten wire toughened silicon carbide ceramic matrix composite material, tungsten wire is used as a toughening phase of the silicon carbide ceramic composite material, and the preparation process of the silicon carbide ceramic matrix composite material is optimized, so that the mechanical properties of the silicon carbide ceramic composite material can be significantly improved;

[0107] The application also provides a tungsten wire toughened silicon carbide ceramic matrix composite material, tungsten wire is used as a toughening phase of the silicon carbide ceramic composite material, and the silicon carbide ceramic composite material has excellent mechanical properties.

[0108] The above only describes the preferred embodiments of the application, and does not limit the patent scope of the application, and any equivalent structural transformation or direct / indirect application in other related technical fields made by using the content of the application specification is included in the patent protection scope of the application.

Claims

1. A method for preparing a tungsten wire toughened silicon carbide ceramic matrix composite material, characterized in that: The following steps are involved: S1, weaving tungsten wire into a first tungsten wire preform; S2. Performing chemical vapor deposition on the first tungsten filament preform using a process gas to obtain a second tungsten filament preform, wherein a silicon carbide coating is formed on a surface of the second tungsten filament preform; S3, impregnating the second tungsten filament preform with silicon carbide slurry and sintering to obtain a third tungsten filament preform, wherein the third tungsten filament preform is filled with a silicon carbide matrix; S4. Repeat step S3 to obtain a tungsten wire toughened silicon carbide ceramic matrix composite material.

2. The method for preparing a tungsten wire toughened silicon carbide ceramic matrix composite material according to claim 1, characterized in that: In the step S1, the specific structure of the first tungsten filament preform includes: a 2.5D structure, a three-dimensional four-directional structure, a three-dimensional five-directional structure or a three-dimensional six-directional structure.

3. The method for preparing a tungsten filament toughened silicon carbide ceramic matrix composite material according to claim 1, characterized in that: In step S2, the process gas includes methylsilane or tetrachloromethylsilane, the temperature of the chemical vapor deposition is 900-1200°C, the pressure of the chemical vapor deposition is 500-9000 Pa, and the thickness of the silicon carbide coating on the surface of the second tungsten filament preform is 50-500 nm.

4. The method for preparing a tungsten filament toughened silicon carbide ceramic matrix composite material according to claim 1, characterized in that: In step S3, the silicon carbide slurry is composed of silicon carbide powder, a solvent, a dispersant, and a defoaming agent, and the content of solid matter in the silicon carbide slurry is 15 wt % to 60 wt %.

5. The method for preparing a tungsten filament toughened silicon carbide ceramic matrix composite material according to claim 4, characterized in that: The particle size of the silicon carbide powder is 50 nm-10 μm; the solvent includes liquid polycarbosilane; the dispersant includes sodium polyacrylate or polycarboxylate; and the defoamer includes a polyether defoamer or a polyoxyethylene-polyoxypropylene block copolymer defoamer.

6. The method for preparing a tungsten filament toughened silicon carbide ceramic matrix composite material according to claim 4, characterized in that: The mass ratio of the solvent, the dispersant and the defoaming agent is (81.9-94.4): (15.6-5.5): (2.5-0.1).

7. The method for preparing a tungsten filament toughened silicon carbide ceramic matrix composite material according to claim 1, characterized in that: In step S3, the immersion pressure is less than 20 Pa, and the immersion time is 5-50 hours.

8. The method for preparing a tungsten filament toughened silicon carbide ceramic matrix composite material according to claim 1, characterized in that: In the step S3, the sintering temperature is 900-1400° C., the sintering time is 1-3 hours, and the sintering is performed in a vacuum, nitrogen or argon environment.

9. The method for preparing a tungsten filament toughened silicon carbide ceramic matrix composite material according to claim 1, characterized in that: In step S4, step S3 is repeated 6-13 times.

10. A tungsten wire toughened silicon carbide ceramic matrix composite material, characterized in that: The tungsten wire toughened silicon carbide ceramic matrix composite material is prepared by the preparation method of any one of claims 1 to 9, wherein the density of the tungsten wire toughened silicon carbide ceramic matrix composite material is greater than or equal to 95%, the compressive strength of the tungsten wire toughened silicon carbide ceramic matrix composite material is greater than or equal to 680 MPa, the flexural strength of the tungsten wire toughened silicon carbide ceramic matrix composite material is greater than or equal to 825 MPa, the tensile strength of the tungsten wire toughened silicon carbide ceramic matrix composite material is greater than or equal to 595 MPa, and the fracture toughness of the tungsten wire toughened silicon carbide ceramic matrix composite material is greater than or equal to 25 MPa·m 1 / 2 , the volume fraction of the tungsten wire is 40%-65%.

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