CN105016759A - Rapid preparation method for C/SiC composite material - Google Patents

Abstract

The invention relates to a method for rapidly preparing C/SiC composite materials, which is characterized in that the steps are: 1, adopting a chemical vapor deposition process to deposit a pyrolytic carbon (PyC) interface on the surface of a thin-layer carbon fiber preform; 2, depositing a PyC interface The thin-layer carbon fiber prefabricated body is impregnated with polycarbosilane mixed solution, and then cross-linked, solidified, and cracked sequentially under a protective atmosphere to obtain a thin-layer C/SiC composite material; 3. Repeat the previous step 2 to 3 times; 4. Multi-chip single The layered composite material is stacked into a graphite mold for spark plasma sintering, and finally a dense C/SiC composite material is quickly prepared. The invention makes full use of the characteristics of the PIP method for impregnating the thin layer in a short time and the SPS method for rapid sintering, thereby realizing the preparation of C/SiC composite materials, which is suitable for the compaction of small and dense components, and can save 95% of the time compared with the traditional CVI method and PIP method. Significantly improve the density of the composite material and reduce the manufacturing cost of the composite material.

Description

A Rapid Preparation Method of C/SiC Composite Material

technical field

The invention relates to the preparation of C/SiC composite materials in the field of materials, in particular to a process method for rapidly preparing C/SiC composite materials.

Background technique

C/SiC composite material is a new type of ultra-high temperature structural material that has emerged with the development of aerospace technology. It has low density, high strength, high toughness, high temperature resistance, chemical corrosion resistance, ablation resistance, erosion resistance, high hardness and High wear resistance and other characteristics. At present, there are many methods for preparing C/SiC composite materials, and chemical vapor infiltration (Chemical vapor infiltration, CVI) is a method that has been used and commercialized. Patent No. 102690124A discloses a C/SiC ceramic matrix composite material and its preparation method. The method uses CVI to sequentially deposit a pyrolytic carbon interface layer and a silicon carbide matrix on the surface of a carbon fiber preform to obtain a C/SiC composite material. However, the preparation of C/SiC composites by the CVI method has the disadvantages of long preparation period, high cost and complicated process. Document 1 "Xiao Peng, Xu Yongdong, Huang Boyun, Rapid preparation of C/SiC composite materials by CVI method, Journal of Silicates, 2002, 30[2]:240-243". If the production process can be simplified and the preparation cycle of C/SiC composite materials can be shortened, it will be beneficial to further promote the development and application of C/SiC composite materials.

A method for rapidly preparing C/SiC ceramic matrix composites is disclosed in Patent No. 102795871A. The method uses low-molecular liquid polycarbosilane as a precursor, carbon fiber prefabricated parts as a skeleton, and pulse-heated chemical liquid-vapor deposition to prepare C/SiC composite materials.

Patent No. 103342570A discloses a low-cost molten silicon impregnation method for preparing C/SiC composite materials. In the method, carbon felt is impregnated with carbon/silicon carbide slurry and subjected to fusion siliconizing treatment, then impregnated with liquid phenolic resin and carbonized, and finally undergoes secondary fusion siliconization treatment to obtain C/SiC. The process of this method is cumbersome, and the high-temperature molten Si will corrode the carbon fiber, and the residual Si will weaken the high-temperature creep resistance of the composite material.

Patent No. 101224988 discloses a low-temperature preparation method of a C/SIC ceramic matrix composite. The method adopts the process of precursor impregnation and pyrolysis (Precursor Infiltration and Pyrolysis, PIP), and through the process steps of carbon fiber pretreatment, vacuum impregnation, high temperature pyrolysis, and densification, the C/SIC ceramic matrix composite material is prepared under low temperature conditions. This method has a long repetition period, and the prepared matrix will have a large number of shrinkage cracks and holes, and repeated high-temperature cracking will damage the fibers.

Document 3 "Si'an Chen, Haifeng Hu, Yudi Zhang, Xinbo He, Min Mei. Rapid densification of C/SiC composites by joint processes of CLVD and PIP. Materials Letters. 2011,65[19-20]:3137-3139. "In the preparation method using chemical liquid vapor deposition combined with precursor immersion cracking.

Spark plasma sintering (Spark Plasma Sintering, SPS) is a new technology for preparing functional materials. It has the characteristics of fast heating speed, short sintering time, controllable structure, energy saving and environmental protection, etc. It can be used to prepare metal materials, ceramic materials, Composite materials, etc., Document 2 "Zhang Jiuxing, Liu Kegao, Zhou Meiling, Development and Application of Spark Plasma Sintering Technology, Powder Metallurgy Technology, 2002, 20[3]: 129-134".

Document 4 "Alba Centeno, Victoria G. Rocha, Amparo Borrell, Clara Blanco, Adolfo Ferna'ndez. Fabrication of C/SiC composites by combining liquid infiltration process and spark plasma sintering technique. Ceramics International. 2012,38[3]:2171-2175 In ", the resin-based 2D carbon fiber prefabricated body is used, and the mesophase pitch, SiC nanowire particles, and silicon powder are impregnated through a series of liquid phase infiltration processes, and then SPS is used to obtain C/SiC. The process is very complicated.

Contents of the invention

technical problem to be solved

In order to solve the problems of long preparation period, high cost and complicated process in the prior art, and further promote the development and application of C/SiC composite materials, the present invention proposes a method for rapidly preparing C/SiC composite materials by using PIP combined with SPS .

Technical solutions

A kind of rapid preparation method of C/SiC composite material, it is characterized in that the steps are as follows:

Step 1. Depositing the interface layer: using a thin-layer carbon fiber prefabricated body with a thickness of less than 0.3 mm as a composite material reinforcement, and depositing a pyrolytic carbon PyC interface on the thin-layer carbon fiber prefabricated body by chemical vapor infiltration;

Step 2, solution preparation: weigh 0-20wt% sintering aid, mix with polycarbosilane PCS, and use magnetic stirring for 4-20h until uniform;

Step 3, matrix preparation: immerse the thin-layer carbon fiber prefabricated body deposited on the PyC interface in step 1 in the solution prepared in step 2 for 1-10 hours, then cross-link and solidify at 200-250°C for 2-3 hours under a protective atmosphere, and continue to heat at 800-250°C for 2-3 hours. Pyrolysis at 900°C for 2 to 3 hours to obtain a thin-layer composite material: repeat this step, so that the density of the thin-layer composite material exceeds 80%; the protective atmosphere is vacuum or argon;

Step 4. Composite material preparation: Laminate multiple sheets of single-layer thin-layer composite materials prepared in step 3 into a graphite mold for spark plasma sintering. The sintering temperature is 1500-1900°C, the load is 30-100Mpa, and the holding time is 2 ~10min, a dense C/SiC composite material was prepared.

Repeat this step in step 3 for 2 to 3 times.

In the step 1, the precursor is propylene, methane, acetylene, ethylene or other hydrocarbons when the pyrolytic carbon PyC interface is deposited on the thin-layer carbon fiber preform by chemical vapor infiltration; the conditions are: argon is used as the dilution gas, The deposition temperature is 750-1100° C., and the time is 10-20 hours; then heat treatment is performed at 1600-1800° C. for 0.5-2 hours.

The thin-layer carbon fiber prefabricated body is one or more of two-dimensional carbon cloth, two-dimensional semi-carbon fiber thin-layer braided body, three-dimensional carbon fiber thin-layer braided body and thin-layer carbon fiber needle felt.

The sintering aid used in step 4 is one or more of alumina, magnesia, zirconia, yttrium oxide, ytterbium oxide, erbium oxide, scandium oxide, cerium oxide and other rare earth oxides.

The total content of the sintering aid is 5-20 wt%.

The multi-piece single-layer thin-layer composite material in the step 4 is 10-30 pieces.

Beneficial effect

The method for rapidly preparing a C/SiC composite material involved in the present invention adopts a precursor impregnation pyrolysis (PIP) process combined with a spark plasma sintering (SPS) process to rapidly prepare a C/SiC composite material. The beneficial effect is: the invention fully utilizes the advantages of the PIP method and the SPS method to rapidly prepare the fiber-reinforced C/SiC composite material. This method utilizes the characteristics of the PIP method to impregnate the thin layer in a short time and the SPS method to sinter quickly, so as to realize the preparation of C/SiC composite materials, which is suitable for the densification of small and dense components, and can save 95% of the time compared with the traditional CVI method and PIP method, and significantly Improve the density of composite materials and reduce the manufacturing cost of composite materials. Figure 2 is a photo of the C/SiC composite prepared by SPS.

Description of drawings

Fig. 1 is the process flow diagram of the rapid preparation of C/SiC composite material of the present invention;

Figure 2 is a photo of the C/SiC composite prepared by SPS.

Detailed ways

Now in conjunction with embodiment, accompanying drawing, the present invention will be further described:

Example 1

Step 1: Depositing the interface layer: using a thin-layer carbon fiber prefabricated body with a thickness of less than 0.3 mm as a composite material reinforcement, and depositing a pyrolytic carbon (PyC) interface by chemical vapor infiltration. During pyrolysis, the precursor is propylene, methane, acetylene, ethylene or other hydrocarbons; the conditions are: argon is used as the dilution gas, the deposition temperature is 750-1100°C, and the time is 10-20h; and then at 1600-1800°C Heat treatment 0.5 ~ 2h;

Step 2: Solution preparation: weighing 0-20wt% aluminum oxide or earth metal oxide and 0-20wt% rare earth oxide as sintering aids, and mixing them with polycarbosilane (PCS). Use magnetic stirring for 4 ~ 20h until uniform.

Step 3: Matrix preparation: The thin-layer carbon fiber preform deposited on the PyC interface is immersed in the mixed solution for 1-10 hours, taken out, and then cross-linked and cured at 200-250°C for 2-3 hours under a protective atmosphere, and cracked at 800-900°C for 2-3 hours to obtain thin-layer composites.

Repeat this step 2 to 3 times until the density of the thin-layer composite material exceeds 80%.

Step 4: Composite material preparation: Laminate 10-30 pieces of single-layer composite materials and put them into graphite molds for spark plasma sintering. The sintering temperature is 1500-1900°C, the load is 70Mpa, the holding time is 2-10min, and the final fast A dense C/SiC composite material was prepared.

Example 2

Step 1: Depositing the interface layer: using a thin-layer carbon fiber prefabricated body with a thickness of less than 0.3 mm as a composite material reinforcement, and depositing a pyrolytic carbon (PyC) interface by chemical vapor infiltration. During pyrolysis, the precursor is propylene, methane, acetylene, ethylene or other hydrocarbons; the conditions are: argon is used as the dilution gas, the deposition temperature is 750-1100°C, and the time is 10-20h; and then at 1600-1800°C Heat treatment 0.5 ~ 2h;

Step 2: Solution preparation: weighing 0-20wt% aluminum oxide or earth metal oxide and 0-20wt% rare earth oxide as sintering aids, and mixing them with polycarbosilane (PCS). Use magnetic stirring for 4 ~ 20h until uniform.

Step 3: Matrix preparation: The thin-layer carbon fiber preform deposited on the PyC interface is immersed in the mixed solution for 1-10 hours, taken out, and then cross-linked and cured at 200-250°C for 2-3 hours under a protective atmosphere, and cracked at 800-900°C for 2-3 hours to obtain thin-layer composites.

Repeat this step 2 to 3 times until the density of the thin-layer composite material exceeds 80%.

Step 4: Composite material preparation: Laminate 10-30 single-layer composite materials and put them into graphite molds for spark plasma sintering. The sintering temperature is 1500-1900°C, the load is 80Mpa, the holding time is 2-10min, and the final fast A dense C/SiC composite material was prepared.

Example 3

Step 1: Depositing the interface layer: using a thin-layer carbon fiber prefabricated body with a thickness of less than 0.3 mm as a composite material reinforcement, and depositing a pyrolytic carbon (PyC) interface by chemical vapor infiltration. During pyrolysis, the precursor is propylene, methane, acetylene, ethylene or other hydrocarbons; the conditions are: argon is used as the dilution gas, the deposition temperature is 750-1100°C, and the time is 10-20h; and then at 1600-1800°C Heat treatment 0.5 ~ 2h;

Step 2: Solution preparation: weighing 0-20wt% aluminum oxide or earth metal oxide and 0-20wt% rare earth oxide as sintering aids, and mixing them with polycarbosilane (PCS). Use magnetic stirring for 4 ~ 20h until uniform.

Step 3: Matrix preparation: The thin-layer carbon fiber preform deposited on the PyC interface is immersed in the mixed solution for 1-10 hours, taken out, and then cross-linked and cured at 200-250°C for 2-3 hours under a protective atmosphere, and cracked at 800-900°C for 2-3 hours to obtain thin-layer composites.

Repeat this step 2 to 3 times until the density of the thin-layer composite material exceeds 80%.

Step 4: Composite material preparation: Laminate 10-30 pieces of single-layer composite materials and put them into graphite molds for spark plasma sintering. The sintering temperature is 1500-1900°C, the load is 90Mpa, the holding time is 2-10min, and the final fast A dense C/SiC composite material was prepared.

Claims (7)

1. a fast preparation method for C/SiC matrix material, is characterized in that step is as follows:

Step 1, deposited interfacial layer: adopt thickness to be less than the coating carbon fibre precast body of 0.3mm as composite material reinforcement body, adopt chemical vapor infiltration to deposit RESEARCH OF PYROCARBON PyC interface on coating carbon fibre precast body;

Prepared by step 2, solution: weigh 0 ~ 20wt% sintering aid, mix with Polycarbosilane PCS, uses magnetic agitation 4 ~ 20h to even;

Prepared by step 3, matrix: coating carbon fibre precast body step 1 being deposited PyC interface is immersed in 1 ~ 10h in solution prepared by step 2, then 200 ~ 250 DEG C of crosslinking curing 2 ~ 3h under protective atmosphere, continue cracking 2 ~ 3h at 800 ~ 900 DEG C, obtain thin multilayer composite material: repeat this step, make thin multilayer composite material density more than 80%; Described protective atmosphere is vacuum or argon gas;

Prepared by step 4, matrix material: thin layer composite lay multi-disc step 3 prepared is put into graphite jig and carried out discharge plasma sintering, sintering temperature is 1500 ~ 1900 DEG C, load is 30 ~ 100Mpa, dwell time 2 ~ 10min, prepares fine and close C/SiC matrix material.

2. the fast preparation method of C/SiC matrix material according to claim 1, is characterized in that: this step of repetition in described step 3 is 2 ~ 3 times.

3. the fast preparation method of C/SiC matrix material according to claim 1, is characterized in that: when adopting chemical vapor infiltration to deposit RESEARCH OF PYROCARBON PyC interface in described step 1 on coating carbon fibre precast body, precursor is propylene, methane, acetylene, ethene or other hydrocarbon polymers; Condition is: take argon gas as diluent gas, and depositing temperature is 750 ~ 1100 DEG C, and the time is 10 ~ 20h; Then at 1600 ~ 1800 DEG C of thermal treatment 0.5 ~ 2h.

4. the fast preparation method of C/SiC matrix material according to claim 1, is characterized in that: described coating carbon fibre precast body is one or more in two-dimentional carbon cloth, two-dimentional half carbon fiber thin layers of woven body, three-dimensional carbon fibre thin layer knitted body and coating carbon fibre Nomex.

5. the fast preparation method of C/SiC matrix material according to claim 1, is characterized in that: the sintering aid that described step 4 uses is one or more in aluminum oxide, magnesium oxide, zirconium white, yttrium oxide, ytterbium oxide, Erbium trioxide, Scium trioxide, cerium oxide and other rare earth oxides.

6. the fast preparation method of C/SiC matrix material according to claim 1 or 5, is characterized in that: described sintering aid total content is 5 ~ 20wt%.

7. the fast preparation method of C/SiC matrix material according to claim 1, is characterized in that: in described step 4, multi-disc thin layer matrix material is 10 ~ 30.