Preparation method of high-thermal-conductivity ultrahigh-temperature modified C / SiC composite material

Abstract

The invention relates to a preparation method of a high-thermal-conductivity ultra-high-temperature modified C / SiC composite material, belongs to the technical field of preparation of modified ceramic-based composite materials, and solves the technical problem of low thermal conductivity of the ultra-high-temperature modified C / SiC composite.The preparation method comprises the steps that a prefabricated body is prepared, and a C / C blank I is obtained; performing graphitization treatment to obtain a C / C blank II; carrying out densification treatment on the C / C blank II by adopting a chemical vapor infiltration method to obtain a C / C blank III; zrC / ZrB2 ultrahigh-temperature particles are introduced into the C / C blank III through a slurry impregnation method, and a C / C-UHTCs composite material I is obtained; carrying out densification treatment on the C / C-UHTCs composite material I by adopting a precursor impregnation pyrolysis method to obtain a C / C-UHTCs composite material II; and performing densification treatment on the C / C-UHTCs composite material II by adopting a reaction infiltration method to obtain the high-thermal-conductivity ultrahigh-temperature modified C / SiC composite material.

Description

Technical Field

[0001] The invention belongs to the technical field of preparation of modified ceramic-based composite materials, and in particular relates to a method for preparing a high thermal conductivity ultrahigh temperature modified C / SiC composite material. Background Art

[0002] As the surface ablation temperature of high-speed aircraft thermal protection structural parts and components in service becomes higher and higher, the ablation environment becomes more and more harsh. Under long-term flight conditions, although the C / SiC-UHTCs composites pre-prepared with traditional polyacrylonitrile PAN-based fibers can meet the service environment requirements of about 2000℃. However, on the one hand, due to the extremely harsh external aerodynamic thermal environment, on the other hand, due to the difficulty of graphitization of traditional polyacrylonitrile-based fibers themselves, the overall thermal conductivity of the composite material is low, resulting in a high ablation stagnation temperature of the component, which leads to rapid accumulation of heat, resulting in increased thermal stress and deformation of the component, exacerbating the risk of damage to the composite component, resulting in low reliability of the material in high-temperature environments. Interphase pitch-based carbon fibers and their composites have the characteristics of low density, low thermal expansion coefficient, high graphitization, and good thermal conductivity. They are one of the thermal protection materials that can meet the higher temperature service environment of future high-speed aircraft. Therefore, the high thermal conductivity mesophase asphalt-based carbon fiber is used as a reinforcement to bear the load and transfer heat, which can not only retain the excellent mechanical properties and high temperature resistance of the composite material, but also overcome its disadvantage of low thermal conductivity, ensure that the composite material has a high thermal conductivity, and improve the temperature resistance limit and reliability of the composite material. Compared with traditional polyacrylonitrile-based fibers, the force between the graphite layers of high thermal conductivity mesophase asphalt-based carbon fibers is relatively small, which leads to lower tensile strength than traditional polyacrylonitrile-based carbon fibers, poor preform weaving process performance, and difficulty in preform molding. Secondly, the diameter of mesophase asphalt-based carbon fibers is usually greater than 10μm, which is 1.5 to 2 times that of traditional polyacrylonitrile-based carbon fibers. The size effect will affect the densification of the fiber preform. Therefore, further improving the thermal conductivity of the composite material, quickly draining the heat of the ablation site, and improving the densification of the composite material have become an urgent problem to be solved. Summary of the invention

[0003] In order to overcome the shortcoming of low thermal conductivity of ultra-high temperature modified C / SiC composite materials of PAN matrix carbon fibers, the present invention provides a preparation method of ultra-high temperature modified C / SiC composite materials with high thermal conductivity.

[0004] The technical solution adopted by the present invention to solve the technical problem is:

[0005] A method for preparing a high thermal conductivity ultra-high temperature modified C / SiC composite material comprises the following steps:

[0006] Step S1, preparing a preform

[0007] The mesophase pitch carbon fiber is subjected to a three-dimensional needle punching method to obtain a mesophase pitch carbon fiber preform and obtain a C / C embryo body I.

[0008] Step S2: Graphitization treatment

[0009] The C / C embryo body I was graphitized to prepare a pyrolytic carbon interface, thereby obtaining a C / C embryo body II.

[0010] Step S3, C / C embryo II densification treatment

[0011] The C / C embryo body II was densified by chemical vapor infiltration to obtain C / C embryo body III.

[0012] Step S4: Ultra-high temperature particles are introduced

[0013] The ZrC / ZrB2 ultrahigh temperature particles were introduced into the C / C embryo III by the slurry impregnation method to obtain the C / C-UHTCs composite material I.

[0014] Step S5, densification treatment of C / C-UHTCs composite material I

[0015] The C / C-UHTCs composite material I was densified by the precursor impregnation and pyrolysis method to obtain the C / C-UHTCs composite material II.

[0016] Step S6: densification treatment

[0017] The C / C-UHTCs composite material II was densified by reactive melt infiltration to obtain a high thermal conductivity ultrahigh temperature modified C / SiC-UHTCs ceramic matrix composite material, namely a high thermal conductivity ultrahigh temperature modified C / SiC composite material.

[0018] In the above preparation method, in step S1, in preparing the preform, the volume fraction of the preform is 30% to 35%.

[0019] In the above preparation method, in step S2, during the graphitization treatment, the graphitization treatment process is:

[0020] The graphitization temperature is 2800°C to 3000°C, the protective atmosphere is argon, the heating rate is 5°C / min to 10°C / min, and the insulation time is 60min to 120min.

[0021] In the above preparation method, in step S3, during the densification treatment of the C / C embryo II, the densification treatment process is:

[0022] The carbon source is methane, and the methane flow rate is 0.4L / min-0.8L / min; the protective gas is argon, and the argon flow rate is 1.0L / min~3.0L / min; the deposition temperature is 1000℃~1100℃, and the deposition time is 20h-30h.

[0023] In the above preparation method, in step S4, during the introduction of ultra-high temperature particles, the particle size of the ZrC / ZrB2 ultra-high temperature particles is 100nm to 5μm.

[0024] In the above preparation method, in step S4, in the introduction of ultra-high temperature particles, the ultra-high temperature particles can also be one of HfC, HfB2, ZrC, ZrB2, or TaC, or a combination of several particles.

[0025] In the above preparation method, in step S5, in the densification treatment of the C / C-UHTCs composite material I, a phenolic resin organic solution is used as a precursor solution.

[0026] In the above preparation method, in step S6, during the densification treatment, the particle size of the melt particles used in the reaction infiltration method is 500nm to 5mm.

[0027] In the above preparation method, in step S6, during the densification treatment, the raw material of the reactive infiltration method is silicon, or a binary alloy, or a ternary alloy.

[0028] The beneficial effects of the present invention are:

[0029] A method for preparing a high thermal conductivity ultra-high temperature modified C / SiC composite material, a high thermal conductivity mesophase asphalt-based carbon fiber three-dimensional needle-punched preform was prepared, and a zirconium-modified composite material was prepared by the SI+CVI+PIP+RMI combined process. This process can not only combine the advantages of each process, but also obtain a preform with a more uniform pore distribution, which is very friendly to the subsequent densification process. Secondly, it also ensures the high thermal conductivity of the composite material, while taking into account the mechanical and anti-ablation properties of the composite material.

[0030] A method for preparing a high thermal conductivity ultra-high temperature modified C / SiC composite material, wherein a carbon matrix prepared by a chemical vapor infiltration method can hinder partial erosion of subsequent silicon melt, protect a pyrolytic carbon interface layer and an intermediate phase asphalt-based fiber, and the strength damage of the fiber and the interface layer is low.

[0031] A method for preparing a high thermal conductivity ultrahigh temperature modified C / SiC composite material, which adopts a solid phase method to introduce UHTCs particles, has simple process operation, and has the advantages of low cost, short cycle, high introduction amount, uniform distribution, etc., and has excellent chemical and physical stability.

[0032] A method for preparing a high thermal conductivity ultrahigh temperature modified C / SiC composite material adopts a solid phase method to not only increase the content of UHTCs particles in the matrix, but also the UHTCs particles as a reinforcement phase can effectively increase the matrix cracking stress and increase the matrix crack propagation path.

[0033] A method for preparing a high thermal conductivity ultra-high temperature modified C / SiC composite material, wherein the prepared C / SiC-ZrB2-ZrC composite material has a density of 2.33 g / cm 3 The porosity is only 4.3%, and the thermal conductivity in the thickness direction is 41.87W / mK, which has excellent thermal conductivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a process flow chart of a method for preparing a modified C / SiC composite material according to an embodiment of the present invention;

[0035] Figure 2 This is a microscopic morphology of the pyrolytic carbon interface layer of the modified C / SiC composite material prepared in an embodiment of the present invention;

[0036] Figure 3 This is a microscopic morphology of the pyrolyzed carbon matrix of the modified C / SiC composite material prepared in an embodiment of the present invention;

[0037] Figure 4 Polarized light microscope image of the pyrolyzed carbon matrix of the modified C / SiC composite material prepared in an embodiment of the present invention;

[0038] Figure 5 This is a microscopic morphology of the modified C / SiC composite material after slurry impregnation according to an embodiment of the present invention;

[0039] Figure 6 This is a microscopic morphology of the modified C / SiC composite material after reactive solution infiltration according to an embodiment of the present invention. DETAILED DESCRIPTION

[0040] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0041] Embodiment 1

[0042] A method for preparing a high thermal conductivity ultra-high temperature modified C / SiC composite material comprises the following steps:

[0043] (1) A mesophase pitch carbon fiber preform is subjected to a three-dimensional needle-punching method to obtain a C / C embryo body I. The C / C embryo body I is a three-dimensional needle-punched structure, all of which are mesophase pitch-based carbon fibers, and the volume fraction of the preform is 30% to 35%.

[0044] (2) After the C / C embryo body I is graphitized, a chemical vapor infiltration method is used to perform pyrolytic carbon interface treatment on the C / C embryo body I to obtain a C / C embryo body II. The graphitization treatment temperature is 2800-3000° C., the protective atmosphere is argon, the heating rate is 5-10° C. / min, and the holding time is 60-120 min.

[0045] (3) The C / C embryo II is subjected to a chemical vapor infiltration method to densify the carbon matrix to obtain a C / C embryo III. The carbon source of the chemical vapor infiltration carbon matrix is ​​methane with a flow rate of 0.4-0.8 L / min; argon is used as a protective gas with a flow rate of 1.0-3.0 L / min; the deposition temperature is 1000-1100°C and the deposition time is 20-30 hours.

[0046] (4) The C / C embryo III is introduced with ZrC / ZrB2 ultrahigh temperature particles by a slurry impregnation method to obtain a C / C-UHTCs composite material I. The ultrahigh temperature particles selected by the slurry impregnation method include, but are not limited to, a combination of one or more particles of HfC, HfB2, ZrC, ZrB2, TaC, etc., and the particle size is 100nm to 5μm.

[0047] (5) The C / C-UHTCs composite material I is densified by using a precursor impregnation and pyrolysis method to obtain the C / C-UHTCs composite material II. The precursor liquid used in the precursor impregnation and pyrolysis method is a phenolic resin organic solution.

[0048] (6) The C / C-UHTCs composite material II is subjected to densification treatment by a reaction melt infiltration method to obtain a high thermal conductivity ultra-high temperature modified C / SiC-UHTCs ceramic matrix composite material. The raw materials of the reaction melt infiltration method include but are not limited to silicon, binary alloys and ternary alloys, and the particle size of the solution particles is 500nm to 5mm.

Claims

1. A method for preparing a high thermal conductivity ultra-high temperature modified C / SiC composite material, characterized in that: The following steps are involved: Step S1, preparing a preform: The mesophase pitch carbon fiber is subjected to three-dimensional needle punching to obtain a mesophase pitch carbon fiber preform, namely C / C embryo body I; Step S2, graphitization treatment: The C / C embryo body I is graphitized to prepare a pyrolytic carbon interface to obtain a C / C embryo body II; Step S3, C / C embryo body II densification treatment: The C / C embryo body II is densified by chemical vapor infiltration to obtain C / C embryo body III; Step S4, ultra-high temperature particles introduction: The ZrC / ZrB2 ultrahigh temperature particles were introduced into the C / C embryo III by the slurry impregnation method to obtain the C / C-UHTCs composite material I; Step S5, densification treatment of C / C-UHTCs composite material I: The C / C-UHTCs composite material I was densified by using the precursor impregnation and pyrolysis method to obtain the C / C-UHTCs composite material II; Step S6, densification treatment: The C / C-UHTCs composite material II was densified by reactive melt infiltration to obtain a high thermal conductivity ultrahigh temperature modified C / SiC-UHTCs ceramic matrix composite material, namely a high thermal conductivity ultrahigh temperature modified C / SiC composite material.

2. The preparation method according to claim 1, characterized in that: In the step S1, in preparing the preform, the volume fraction of the preform is 30% to 35%.

3. The preparation method according to claim 2, characterized in that: In the step S2, graphitization treatment, the graphitization treatment process is: The graphitization temperature is 2800°C to 3000°C, the protective atmosphere is argon, the heating rate is 5°C / min to 10°C / min, and the insulation time is 60min to 120min.

4. The preparation method according to claim 3, characterized in that: In the step S3, during the densification treatment of the C / C embryo II, the densification treatment process is as follows: The carbon source is methane, and the methane flow rate is 0.4L / min-0.8L / min; the protective gas is argon, and the argon flow rate is 1.0L / min~3.0L / min; the deposition temperature is 1000℃~1100℃, and the deposition time is 20h-30h.

5. The preparation method according to claim 4, characterized in that: In the step S4, the ultra-high temperature particles are introduced, and the particle size of the ZrC / ZrB2 ultra-high temperature particles is 100nm to 5μm.

6. The preparation method according to claim 4, characterized in that: In the step S4, in the introduction of ultra-high temperature particles, the ultra-high temperature particles may be one of HfC, HfB2, ZrC, ZrB2, or TaC, or a combination of several particles.

7. The preparation method according to claim 5, characterized in that: In the step S5, in the densification treatment of the C / C-UHTCs composite material I, a phenolic resin organic solution is used as a precursor solution.

8. The preparation method according to claim 7, characterized in that: In the step S6, during the densification treatment, the particle size of the solution particles used in the reaction infiltration method is 500nm to 5mm.

9. The preparation method according to claim 7, characterized in that: In the step S6, during the densification treatment, the raw material of the reactive infiltration method is silicon, or a binary alloy, or a ternary alloy.

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