CN108727049B

CN108727049B - CfSiC-HfC ultrahigh-temperature ceramic matrix composite and preparation method thereof

Info

Publication number: CN108727049B
Application number: CN201710266135.6A
Authority: CN
Inventors: 董绍明; 曹艳鹏; 倪德伟; 周海军; 高乐; 阚艳梅
Original assignee: Shanghai Institute of Ceramics of CAS
Current assignee: Jiaxingrui Innovative Materials Co ltd
Priority date: 2017-04-21
Filing date: 2017-04-21
Publication date: 2021-03-19
Anticipated expiration: 2037-04-21
Also published as: CN108727049A

Abstract

The invention relates to a compound C_fThe preparation method of the/SiC-HfC ultrahigh-temperature ceramic matrix composite material comprises the following steps: by vacuum impregnationIntroduction of HfO into carbon fiber preforms₂Powder and carbon source to obtain C_f/HfO₂-C preform; subjecting the obtained C to_f/HfO₂Placing the-C preformed body in an inert atmosphere, and performing carbothermic reduction for 1-2 hours at 1300-1800 ℃ to obtain C_fa/HfC-C preform; subjecting the obtained C to_fPerforming Si infiltration on the/HfC-C preformed body at 1400-1700 ℃ to ensure that C is infiltrated_fC and Si in-situ reaction in the/HfC-C preformed body to generate a SiC matrix phase to obtain C_fThe composite material is a SiC-HfC ultrahigh-temperature ceramic matrix composite material. The preparation temperature is low, and the damage of high temperature to carbon fiber in the preparation process of the material is reduced; simple process and easy realization of C_fAnd rapidly preparing the/SiC-HfC composite material.

Description

CfSiC-HfC ultrahigh-temperature ceramic matrix composite and preparation method thereof

Technical Field

The invention relates to a compound C_fA preparation method of a/SiC-HfC ultrahigh temperature ceramic matrix composite material belongs to the field of ultrahigh temperature ceramic preparation.

Background

The hypersonic aircraft technology is known as the next generation flight technology, and is the third epoch-making milestone after the aircraft is invented and the sound barrier is broken through in the aviation history. When the hypersonic aircraft reciprocates and enters the atmosphere again, the local surface needs to bear the high temperature of more than 2000 ℃, the high-pressure airflow of dozens of megapascals and the violent scouring of high-energy particles. Therefore, the research and development of high-temperature structural materials with high temperature resistance, oxidation ablation resistance and high strength is one of the important key technologies, and plays a significant role in the development process of the hypersonic aircraft.

C_fthe/SiC composite material has excellent comprehensive performance and is believed to beIs the high-temperature structural material with the most development potential. However, C_fThe temperature limit of the/SiC composite material in long-time use is generally not more than 1650 ℃, and ultra-high temperature phase (such as ZrC and ZrB) is introduced into the SiC matrix₂、HfC、HfB₂Etc.) can effectively increase C_fThe service temperature of the/SiC composite material is upper limit. HfC is the highest melting point material (3890 ℃) known at present, has extreme high temperature resistance, and is oxidized to produce HfO₂The melting point also reaches 2900 ℃, the chemical stability is good, and HfO formed in the ablation process₂The interior of the material may continue to be protected. However, it is currently difficult to prepare high performance C due to the limitations of the preparation process_fThe composite material is a SiC-HfC ultrahigh-temperature ceramic matrix composite material.

The document "Jinming Jiang, Song Wang, Wei Li, et al preparation of 3D Cf/ZrC-SiC compositions by joint processes of PIP and RMI [ J]Materials Science and Engineering, A, Volume 607,23June 2014, Pages 334-. Reaction Infiltration (RMI) is an effective way to rapidly prepare near-net-shape complex-shaped members, although it can prepare a compact and substantially defect-free matrix by one-step molding, and has become one of the hot spots developed by ultrahigh-temperature ceramic-based composite materials at home and abroad in recent years. However, HfSi₂The melting point of the alloy is high, and if the alloy is directly infiltrated, the fiber and the interface are eroded, so that the high-temperature performance of the material is influenced. Synthesis C_fThe research situation of the/SiC-HfC ultrahigh temperature ceramic matrix composite requires urgent development of a novel preparation process.

Disclosure of Invention

The present invention is directed to C_fThe problem of the existing preparation process of the/SiC-HfC material is to provide C_fThe preparation method of the/SiC-HfC ultrahigh-temperature ceramic matrix composite material comprises the following steps:

introduction of HfO into carbon fiber preforms by means of vacuum impregnation₂Powder and carbon source to obtain C_f/HfO₂-C preform;

subjecting the obtained C to_f/HfO₂-C preformPlacing the mixture in an inert atmosphere, and performing carbothermic reduction for 1-2 hours at 1300-1800 ℃ to obtain C_fa/HfC-C preform;

subjecting the obtained C to_fPerforming Si infiltration on the/HfC-C preformed body at 1400-1700 ℃ to ensure that C is infiltrated_fC and Si in-situ reaction in the/HfC-C preformed body to generate a SiC matrix phase to obtain C_fThe composite material is a SiC-HfC ultrahigh-temperature ceramic matrix composite material.

The invention selects HfO₂Using the powder as a hafnium source, and impregnating the raw material (HfO) with a vacuum₂Powder and carbon source) into the carbon fiber preform to obtain C_f/HfO₂-C preform. Then carrying out high-temperature carbothermic reduction (1300-1800 ℃) to ensure that C is obtained_f/HfO₂-hafnium source HfO in C preform₂Reacting with carbon source C to obtain HfC + CO, and finally generating C with nano-porosity_fa/HfC-C preform. Then, introducing Si at 1400-1700 ℃ by adopting an RMI method and utilizing the action of the formed nano-porous capillary force, so that Si and C_fC, carrying out in-situ reaction on carbon source C which is not completely reacted in the/HfC-C preformed body to generate a SiC matrix phase, and finally obtaining C_fThe composite material is a/SiC-HfC ultrahigh-temperature ceramic matrix composite material. The main reactions involved in the present invention include: c, carbothermic reduction reaction: HfO₂+ C → HfC + CO; infiltration reaction: si + C → SiC. Therefore, the ultrahigh-temperature ceramic matrix composite material prepared by the method has good mechanical property, HfC crystal grains generated by in-situ reaction are fine, the volume content is high, and the ablation resistance of the material is effectively improved.

Preferably, the HfO₂The mass ratio of the powder to the carbon fiber preform is 1: (0.26-0.52).

Preferably, the carbon source is an inorganic carbon source or an organic carbon source, and the mass ratio of the carbon source to the carbon fiber preform is 1: (1.08-1.78). The carbon source is preferably an organic carbon source, and a liquid carbon source precursor can more easily enter the material and HfO₂The particles completely react to generate HfC and can enter the fiber bundle, so that the simple substance Si reacts with the cracked C in the later infiltration process, and the C fiber is protected from being damaged; more preferably a phenolic resin. The invention is produced by cracking reaction of organic carbon sourceBetter regulation of gas C_f/HfO₂-C pore size in the preform.

Preferably, the inorganic carbon source is at least one of carbon black, graphite powder, and carbon powder, and the organic carbon source is at least one of phenol resin, furan resin, and silane resin.

Preferably, when the carbon source is an organic carbon source or a mixture of an organic carbon source and an inorganic carbon source, the resulting C is_f/HfO₂the-C pre-formed body is dried and cracked, and then is subjected to carbothermic reduction.

Preferably, the drying is performed by heat preservation at 80-120 ℃ for 3-6 hours, and the cracking is performed by heat preservation at 600-900 ℃ for 1-2 hours.

Preferably, the vacuum degree of the vacuum impregnation method is-0.08 to-0.10 MPa.

Preferably, the carbon fiber preform has a structure of three-dimensional needling, two-dimensional lamination or three-dimensional weaving, and the air opening rate is 30-50 vol%. Preferably, a pyrolytic carbon PyC or pyrolytic carbon PyC/SiC composite multilayer interface with the thickness of 500-1500 nm is deposited on the surface of the fiber in the carbon fiber preform. The interface is too thin, so that the matrix and the fibers are strongly bonded, the fibers are brittle and broken in the breaking process, the toughening effect cannot be achieved, the interface is too thick, so that the fibers and the matrix are not tightly bonded, and the mechanical strength of the material is reduced.

Preferably, the Si infiltration atmosphere is a vacuum atmosphere for 0.5 to 3 hours.

In another aspect, the invention also provides C prepared according to the preparation method_fa/SiC-HfC ultra high temperature ceramic matrix composite, said C_fthe/SiC-HfC ultrahigh-temperature ceramic matrix composite material comprises carbon fibers, a SiC phase and a HfC phase, wherein the content of the carbon fibers is 25-40 vol%, and the volume ratio of HfC to SiC is 0.10-0.35.

Preferably, C is_fThe bending strength of the/SiC-HfC ultrahigh-temperature ceramic matrix composite material is 93-125 MPa, and the mass ablation rate at 2000 ℃ is 15.32-18.67 mg/s.

The invention has the beneficial effects that: the scheme realizes infiltration through slurry impregnation and carbothermic reduction processThe pore of the prefabricated body is regulated and controlled, and C is synthesized by combining Si reaction infiltration_fthe/SiC-HfC composite material solves the problem that the traditional reaction infiltration process is difficult to obtain the material; the preparation temperature is low, so that the damage of high temperature to the carbon fiber in the material preparation process is reduced; simple process and easy realization of C_fAnd rapidly preparing the/SiC-HfC composite material.

Drawings

FIG. 1 is C, prepared according to example 1_fAn X-ray diffraction pattern of the surface of the/SiC-HfC composite material;

FIG. 2 is C prepared in example 1_fA low-magnification SEM picture of a polished section of the/SiC-HfC composite material;

FIG. 3 is C prepared in example 1_fHigh-power SEM pictures of polished sections of the/SiC-HfC composite material;

FIG. 4 is C prepared in example 1_fHigh-power SEM pictures of polished sections of the/SiC-HfC composite.

Detailed Description

The present invention is further illustrated by the following examples, which are to be understood as merely illustrative and not restrictive.

The invention is based on a slurry impregnation combined reaction infiltration (RMI) process: respectively with HfO₂Powder, inorganic carbon source or/and organic carbon source (such as phenolic resin) as hafnium source and carbon source, vacuum impregnating, introducing into carbon fiber preform, and carbothermic reducing to obtain porous C_fa/HfC-C preform, then infiltrating the molten Si into the C by infiltration method under certain temperature condition_fIn the/HfC-C preformed body, generating a SiC matrix phase based on Si-C in-situ reaction to obtain C_fThe composite material is a SiC-HfC ultrahigh-temperature ceramic matrix composite material.

In the present invention, C_fthe/SiC-HfC ultrahigh-temperature ceramic matrix composite material comprises carbon fibers, a SiC phase and a HfC phase, wherein the content of the carbon fibers can be 25-40 vol%, and the volume ratio of HfC to SiC is 0.10-0.35. Said C is_fThe bending strength of the/SiC-HfC ultrahigh-temperature ceramic matrix composite material can be 93-125 MPa, and the mass ablation rate at 2000 ℃ can be 15.32-18.67 mg/s.

The invention solves the problem of potteryThe traditional process for preparing the ceramic-based composite material is difficult to prepare the HfC ultrahigh-temperature ceramic-based composite material, and the process is simple and is easy to realize the rapid preparation of the material. The following exemplary description of the invention provides C_fA preparation method of a/SiC-HfC ultrahigh-temperature ceramic matrix composite material.

Carbon fiber preform (C)_f) The pretreatment of (1). In the invention, the structure of the carbon fiber preform can be three-dimensional needling, two-dimensional lamination or three-dimensional weaving. The open porosity of the carbon fiber preform can be 30-50 vol%, and a pyrolytic carbon PyC or pyrolytic carbon PyC/SiC composite multilayer interface with the thickness of 500-1500 nm is deposited on the surface of the fiber in the carbon fiber preform. And ultrasonically cleaning the carbon fiber preform, and then drying the carbon fiber preform in an oven. The ultrasonic cleaning agent can be alcohol, the cleaning time can be 1-3 hours, and the drying condition is that the temperature is kept at 60-80 ℃ for 6-12 hours.

HfO₂And (4) preparing slurry. Dissolving a dispersant PEI into a certain amount of deionized water according to a preset proportion, and carrying out ultrasonic treatment for later use. And then, adjusting the pH value of the PEI solution to 3-5 by using HCl and NaOH solutions, so that a large repulsive force exists between particles, and the slurry is in a stable state. Finally, the HfO weighed in advance is used₂And slowly adding the powder into the PEI solution, and performing ball milling and mixing to obtain uniform slurry. Wherein, HfO₂HfO in slurry₂The mass fraction of the powder can be 70.76-86.58 wt%. Dispersant PEI can be added in an amount of HfO ₂0 to 0.2wt%, preferably 0.05 to 0.2wt% of the powder. The molar concentration of the HCl solution and the NaOH solution can be 0.05-0.2 mol/L, and the pH value is adjusted to 3-5. The ball milling and mixing time can be 12-24 hours.

HfO₂And (4) vacuum impregnation of the slurry. The obtained HfO₂The slurry is introduced into the treated fiber preform by vacuum impregnation and taken out into an oven for drying. Wherein the vacuum impregnation condition is-0.08 MPa to-0.10 MPa of vacuum degree.

Introducing a carbon source. The carbon source can be an inorganic carbon source or/and an organic carbon source. The particle size of the inorganic carbon source can be 10-20 nm, and the inorganic carbon source can be at least one of carbon black, graphite powder and carbon powder. What is needed isThe organic carbon source may be at least one of phenolic resin, furan resin and silane resin. Will be impregnated with HfO₂And continuously vacuum-impregnating the carbon source in the carbon fiber preform of the powder. When the carbon source is an inorganic carbon source, the carbon fiber preform can be directly immersed into slurry containing the inorganic carbon source and then dried to obtain C_f/HfO₂-C preform. The content of the inorganic carbon source in the slurry containing the inorganic carbon source can be 30-40 wt%. When the carbon source is an organic carbon source or a mixture of an organic carbon source and an inorganic carbon source, it is impregnated with HfO₂The carbon fiber preform of the powder is directly immersed in an organic carbon source or a mixed solution of the organic carbon source and an inorganic carbon source, and then is dried and cracked. The drying can be carried out at 80-120 ℃ for 3-6 hours. The cracking can be carried out at 600-900 ℃ for 1-2 hours, and the cracking atmosphere is also inert atmosphere (such as argon). The aim of the invention in drying and cracking is to convert the organic carbon source into C (such as cracking reaction: PR (phenolic resin) → C) and generate more gas in the cracking process, thereby better regulating and controlling C_f/HfO₂The pore structure in the-C preformed body is more beneficial to the subsequent Si infiltration reaction. As an example, will be impregnated with HfO₂Directly immersing the carbon fiber preform of the powder into phenolic resin, drying the sample, and then putting the dried sample into a cracking furnace to crack in inert atmosphere to obtain C_f/HfO₂-C preform. Wherein the vacuum impregnation condition is-0.08 MPa to-0.10 MPa of vacuum degree.

HfO as described above₂Vacuum impregnation of the slurry and introduction of a carbon source can be repeated for 2-4 times. Note that the above hafnium source (HfO)₂Powder) and carbon source vacuum impregnation times are not limited, and only HfO needs to be controlled₂The mass ratio of the powder to the carbon fiber preform is 1: (0.26-0.52) (a large amount of HfO in the carbon fiber preform)₂Ultra-high temperature phase) and the mass ratio of the carbon source to the carbon fiber preform is in the range of 1: (1.08-1.78) (ensuring that the carbon source can react with HfO)₂Complete reaction of Si to form HfC and SiC).

C is to be_f/HfO₂-C preform is subjected to carbothermic reduction reaction under conditions during which it is maintainedInert atmosphere (e.g., Ar atmosphere), carbothermal reduction to obtain C_f/HfC-C(C_fa/HfC-C preform). Wherein the carbothermic reaction is carried out under the condition of heat preservation for 1-2 hours at 1300-1800 ℃.

And (4) infiltration reaction. Infiltrating molten Si into C in a certain temperature and vacuum environment_fHfC-C material (C)_fa/HfC-C preformed body), namely Si infiltration, and in the Si infiltration process, Si reacts with C of cracking C or/and inorganic carbon source in situ to generate SiC matrix phase to obtain the C_fThe composite material is a SiC-HfC ultrahigh-temperature ceramic matrix composite material. Wherein, the Si infiltration condition is heat preservation for 0.5 to 3 hours at 1400 to 1700 ℃, preferably 1 to 3 hours.

In general, the invention adopts the slurry impregnation combined with the reaction melting infiltration process to prepare C_fthe/SiC-HfC ceramic matrix composite material. With HfO₂The powder is a hafnium source, an organic carbon source or/and an inorganic carbon source, and HfO is firstly introduced into the carbon fiber preform by utilizing a vacuum impregnation method₂And a carbon source, and then obtaining porous C by carbothermic reduction_fa/HfC-C preformed body is finally applied to C by an infiltration method by utilizing the action of capillary force_fHfC-C preforms are introduced with molten Si and reacted in situ to obtain C_fThe composite material is a SiC-HfC ultrahigh-temperature ceramic matrix composite material. In the invention, the main reactions involved include: and (3) cracking reaction: organic carbon source (e.g., (Novolac PR) → C; carbothermic reduction: HfO₂+ C → HfC + CO; infiltration reaction: si + C → SiC.

The invention adopts an Instron-5566 type electronic universal tester to measure C_fThe three-point bending strength of the/SiC-HfC ultrahigh-temperature ceramic matrix composite material can be 93-125 MPa. C is measured by adopting 30kW air plasma material high-temperature test equipment_fThe mass ablation rate of the/SiC-HfC ultrahigh-temperature ceramic matrix composite material at 2000 ℃ is 15.32-18.67 mg/s.

The present invention will be described in detail by way of examples. It is also to be understood that the following examples are illustrative of the present invention and are not to be construed as limiting the scope of the invention, and that certain insubstantial modifications and adaptations of the invention by those skilled in the art may be made in light of the above teachings. The specific process parameters and the like of the following examples are also only one example of suitable ranges, i.e., those skilled in the art can select the appropriate ranges through the description herein, and are not limited to the specific values exemplified below.

Example 1

(1) And (3) processing the prefabricated body: carrying out alcohol ultrasonic cleaning on a carbon fiber preform (the interface is a PyC/SiC composite three-layer interface with the thickness of 500nm and the mass is 11.62g) with the open porosity of 30 vol%, wherein the cleaning time is 1 hour;

(2) preparing slurry: will occupy HfO₂Dissolving 0.1 wt% of PEI in a certain amount of deionized water, and carrying out ultrasonic treatment for later use; then using 0.1 mol.L^-1Adjusting the pH value of the PEI solution to 3 by using HCl and NaOH solution; then the HfO weighed in advance₂Slowly adding the powder into the PEI solution, and ball-milling and mixing for 24h to obtain HfO₂Powder slurry (HfO therein)₂The mass fraction of the powder is 86.58%);

(3) vacuum impregnation of slurry: subjecting HfO obtained in step (2)₂The slurry was introduced into the fiber preform treated in step (1) by vacuum impregnation under a vacuum of-0.08 MPa, followed by drying at 80 ℃ for 8 hours, weighing 53.32, and giving a mass-added fraction (41.7g) of HfO₂Powder of HfO₂The mass ratio of the powder to the carbon fiber preform is 1: 0.27;

(4) introducing a carbon source: vacuum-impregnating the material prepared in the step (3) into phenolic resin, wherein the mass ratio of the introduced phenolic resin to the carbon fiber preform is 1: 1.08. drying the sample, putting into a cracking furnace for cracking, keeping the temperature at 600 ℃ and 900 ℃ for 1 hour respectively, keeping the Ar gas flow of 10L/min in the period, and obtaining C after cracking_f/HfO₂-C；

(5) C, carbothermic reduction: repeating the steps (3) - (4) for 2 times to obtain the final product C_f/HfO₂Putting the-C into a carbon tube furnace for carbothermic reduction reaction, and carrying out the carbothermic reduction reaction at 1600 ℃ for 1 hour to obtain the C_f/HfC-C；

(6) And (3) reaction infiltration: infiltrating molten Si into C under vacuum infiltration condition of 1500 ℃/1h_fThe in-situ reaction in the/HfC-C material generates a SiC matrix phase,and finishing the preparation of the material.

EXAMPLE 1 preparation C_fThe content of carbon fibers in the/SiC-HfC composite material is 30 vol%, and the volume ratio of the HfC phase to the SiC phase is 1: 2.6, the bending strength is 122.57 +/-11.63 MPa, and the mass ablation rate of the material at 2000 ℃ is 15.32 mg/s.

Example 2

Similar to the procedure in example 1, except that the fiber preform had an open porosity of 40% (the interface was a PyC/SiC composite multilayer interface having a thickness of 1000 nm), was impregnated with HfO₂The slurry is dipped in the phenolic resin for one time twice, and the carbothermic reduction temperature is 1500 ℃, and the infiltration temperature is 1450 ℃. This experiment prepared C_fThe content of carbon fibers in the/SiC-HfC composite material is 35 vol%, and the volume ratio of the HfC phase to the SiC phase is 1: 3.2, the bending strength is 103.15 +/-14.35 MPa, and the mass ablation rate of the material at 2000 ℃ is 16.68 mg/s.

Example 3

Similar to the procedure in example 1, except that the fiber preform had an open porosity of 50% (the interface was a PyC/SiC composite multilayer interface having a thickness of 1500nm, and the mass was 13.3g), and was impregnated with HfO₂Slurry two times (HfO)₂The mass ratio of the powder to the carbon fiber preform is 1: 0.52), impregnating twice with a phenolic resin (the mass ratio of the phenolic resin to the carbon fiber preform is 1: 1.53), the carbothermic reduction temperature is 1550 ℃, and the infiltration temperature is 1500 ℃. This experiment prepared C_fThe content of carbon fibers in the/SiC-HfC composite material is 30 vol%, and the volume ratio of the HfC phase to the SiC phase is 1: 3.6, the bending strength is 95.64 +/-12.51 MPa, and the mass ablation rate of the material at 2000 ℃ is 18.67 mg/s.

Example 4

Similar to the procedure in example 1, except that HfO was impregnated₂Slurry two times (HfO)₂The mass ratio of the powder to the carbon fiber preform is 1: 0.31), impregnating twice with a phenolic resin (the mass ratio of the phenolic resin to the carbon fiber preform is 1: 1.65), the carbothermic reduction temperature is 1600 ℃, the time is 0.5 hour, the infiltration temperature is 1500 ℃, and the time is 2 hours. This experiment prepared C_fThe content of carbon fibers in the/SiC-HfC composite material is 32 vol%, and the volume ratio of the HfC phase to the SiC phase is 1:2.8, the bending strength is 93.68 +/-10.95 MPa, and the mass ablation rate of the material at 2000 ℃ is 16.21 mg/s.

Example 5

Similar to the procedure in example 1, except that HfO was impregnated₂Slurry two times (HfO)₂The mass ratio of the powder to the carbon fiber preform is 1: 0.43), impregnating twice with a phenolic resin (the mass ratio of the phenolic resin to the carbon fiber preform is 1: 1.52), the carbothermic reduction temperature is 1600 ℃, the time is 1 hour, the infiltration temperature is 1500 ℃, and the time is 0.5 hour. The content of carbon fiber in the Cf/SiC-HfC composite material prepared by the experiment is 31 ol%, and the volume ratio of the HfC phase to the SiC phase is 1: 3.1, the bending strength is 106.95 +/-12.84 MPa, and the mass ablation rate of the material at 2000 ℃ is 17.36 mg/s.

Example 6

Similar to the procedure in example 1, except that HfO was impregnated₂Slurry two times (HfO)₂The mass ratio of the powder to the carbon fiber preform is 1: 0.37) and dipping the carbon black slurry twice (the particle size of the carbon black is 10-20 nm, and the mass content of the carbon black in the carbon black slurry is 30 wt%. The mass ratio of the carbon black to the carbon fiber preform is 1: 1.62), the carbothermic reduction temperature is 1600 ℃, the time is 1 hour, the infiltration temperature is 1500 ℃, and the time is 0.5 hour. This experiment prepared C_fThe content of carbon fibers in the/SiC-HfC composite material is 33 vol%, and the volume ratio of the HfC phase to the SiC phase is 1: 4.2, the bending strength is 93.51 plus or minus 14.36MPa, and the mass ablation rate of the material at 2000 ℃ is 17.62 mg/s.

Example 7

Similar to the procedure in example 1, except that HfO was impregnated₂Slurry two times (HfO)₂The mass ratio of the powder to the carbon fiber preform is 1: 0.28), soaking the mixed solution of the carbon black and the phenolic resin twice (wherein the particle size of the carbon black is 10-20 nm, and the mass ratio of the carbon black to the phenolic resin is 1: 1, the mass ratio of the total carbon source to the carbon fiber preform is 1: 1.57), the carbothermic reduction temperature is 1600 ℃, the time is 1 hour, the infiltration temperature is 1500 ℃, and the time is 0.5 hour. This experiment prepared C_fThe content of carbon fibers in the/SiC-HfC composite material is 31 vol%, and the volume ratio of the HfC phase to the SiC phase is 1: 2.8, the bending strength is 102.84 +/-11.26 MPa, and the material is taken at 2000 DEG CThe mass ablation rate of the material is 16.24 mg/s.

FIG. 1 is C, prepared according to example 1_fThe X-ray diffraction pattern of the surface of the/SiC-HfC composite material is shown in figure 1, and the pattern has HfC and SiC diffraction peaks which are high in intensity and sharp, so that the HfC and SiC crystallinity in the material is good; and a small amount of HfSi is generated in the material after the reaction₂Alloy of HfSi during ablation₂The alloy can be oxidized to generate HfO₂And SiO₂Absorbing heat and covering the surface of the material to prevent the material from being further damaged;

FIG. 2 is C prepared in example 1_fAnd (3) taking a low-magnification SEM picture of the polished section of the/SiC-HfC composite material, wherein a bright white area in the matrix is an ultrahigh-temperature phase, and a black area is a fiber bundle. From fig. 2, it can be seen that a large amount of the ultra-high temperature phase is distributed among the fiber bundles, and the distribution is less in the interior of the fiber bundles;

FIG. 3 and FIG. 4 are the results of example 1 for preparation C_fHigh-power SEM picture of polished section of/SiC-HfC composite material, from which it can be seen that bright white region is HfC and HfSi₂Phase, white phase is the ultra-high temperature phase HfC, and gray region is the SiC phase. A large amount of HfC and SiC are uniformly distributed in the material, and a small amount of HfSi is arranged₂Distributed in island shape inside the HfC.

Claims

1. C_fThe preparation method of the/SiC-HfC ultrahigh-temperature ceramic matrix composite material is characterized by comprising the following steps of:

sequentially introducing HfO into a carbon fiber preform with an open porosity of 30-50 vol% by using a vacuum impregnation method₂Powder and carbon source to obtain porous C_f/HfO₂-C preform; therein for introducing HfO₂HfO of powder₂The slurry contains a dispersant PEI, the pH of the slurry is 3-5, and HfO is added₂HfO in slurry₂The mass fraction of the powder is 70.76-86.58 wt%, and the addition amount of the PEI is HfO₂0.05-0.2 wt% of the powder and water as a solvent;

mixing the obtained porous C_f/HfO₂Placing the-C preformed body in an inert atmosphere, and performing carbothermic reduction for 1-2 hours at 1300-1800 ℃ to obtain porous C_fHfC-C preformA molded body;

mixing the obtained porous C_fPerforming Si infiltration on the/HfC-C preformed body at 1400-1500 ℃ to ensure that C is infiltrated_fC and Si in-situ reaction in the/HfC-C preformed body to generate a SiC matrix phase to obtain C_fThe composite material is a SiC-HfC ultrahigh-temperature ceramic matrix composite material.

2. The method for preparing as claimed in claim 1, wherein the HfO is₂The mass ratio of the powder to the carbon fiber preform is 1: (0.26-0.52).

3. The method according to claim 1, wherein the carbon source is an inorganic carbon source or/and an organic carbon source, and the mass ratio of the carbon source to the carbon fiber preform is 1: (1.08-1.78).

4. The method according to claim 3, wherein the inorganic carbon source is at least one of carbon black, carbon powder and graphite powder, and the organic carbon source is at least one of phenolic resin, furan resin and silane resin.

5. The method according to claim 3, wherein when the carbon source is an organic carbon source or a mixture of an organic carbon source and an inorganic carbon source, the resulting C is_f/HfO₂the-C pre-formed body is dried and cracked, and then is subjected to carbothermic reduction.

6. The preparation method according to claim 5, wherein the drying is performed by heat preservation at 80-120 ℃ for 3-6 hours, and the cracking is performed by heat preservation at 600-900 ℃ for 1-2 hours.

7. The method according to claim 1, wherein the vacuum degree of the vacuum impregnation method is-0.08 to-0.10 MPa.

8. The method according to claim 1, wherein the carbon fiber preform has a structure of three-dimensional needling, two-dimensional lamination or three-dimensional weaving, and a pyrolytic carbon PyC or a pyrolytic carbon PyC/SiC composite multilayer interface having a thickness of 500 to 1500nm is deposited on the surface of the fiber in the carbon fiber preform.

9. The production method according to any one of claims 1 to 8, wherein the atmosphere of the Si infiltration is a vacuum atmosphere for 0.5 to 3 hours.

10. C prepared according to the preparation method of any one of claims 1 to 9_fthe/SiC-HfC ultrahigh-temperature ceramic matrix composite material is characterized in that C is_fthe/SiC-HfC ultrahigh-temperature ceramic matrix composite material comprises carbon fibers, a SiC phase and a HfC phase, wherein the content of the carbon fibers is 25-40 vol%, and the volume ratio of the HfC phase to the SiC phase is 0.10-0.35.

11. The C of claim 10_fthe/SiC-HfC ultrahigh-temperature ceramic matrix composite material is characterized in that C is_fThe bending strength of the/SiC-HfC ultrahigh-temperature ceramic matrix composite material is 93-125 MPa, and the mass ablation rate at 2000 ℃ is 15.32-18.67 mg/s.