Bn nanotube interfacial phase strengthened and toughened carbon fiber reinforced ceramic matrix composite material and preparation method thereof

Abstract

The invention relates to a BN nanotube interface phase strengthening and toughening carbon fiber reinforced ceramic matrix composite material. The following components are included in terms of mass percentage: h-BN is less than 0.5 wt.%, SiC is 10-30 wt.%, elemental Si is less than 10 wt.% and carbon balance. The preparation method is as follows: using carbon fiber woven cloth or felt body as a raw material, and sequentially performing degumming treatment, precursor impregnation-drying-high temperature heat treatment, matrix carbon densification and molten silicon infiltration process, to obtain BN nanotube interface phase strengthening and toughening carbon fiber Reinforced ceramic matrix composites. The invention makes full use of the good physical and chemical compatibility of BN with carbon fiber and matrix carbon, but does not react with liquid silicon and has the characteristics of poor wettability, and creatively grows BN nanotubes with high strength and large specific surface area protection in the carbon fiber in situ. The carbon fibers that play the main load-bearing function in the C / C-SiC composite material realize the strengthening and toughening of the C / C-SiC composite material prepared by the molten silicon infiltration process, and improve the mechanical properties of the C / C-SiC composite material; at the same time, The invention also improves the fatigue resistance of the C / C-SiC composite material.

Description

technical field [0001] The invention belongs to the technical field of composite materials, and more specifically relates to a BN nanotube interfacial phase reinforced carbon fiber reinforced ceramic matrix composite material and a preparation method thereof. Background technique [0002] Carbon fiber reinforced carbon-silicon carbide double matrix (C / C-SiC) composite material has light weight, high specific strength, high specific modulus, oxidation resistance, corrosion resistance, high friction coefficient, good thermal conductivity, high density and low preparation cost Relatively low and a series of advantages, it is a very competitive new generation of ceramic matrix composite materials, and has broad application prospects in the fields of friction materials, high-temperature thermal structures, and aerospace. [0003] At present, the molten silicon infiltration method (LSI) is mainly used at home and abroad to produce low-cost and high-density C / C-SiC composite materi...

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Problems solved by technology

However, the C / C-SiC composite materials prepared by the LSI process still have the following problems: (1) In high temperature environment, liquid silicon is very easy to corrode the carbon fibers in the C / C porous body, reducing the amount of material available for load-carrying per unit volume inside the material. At the same time, the chemical reaction between silicon and carbon also introduces strong interface bonds such as carbon fiber / SiC and matrix carbon / SiC, resulting in low strength and poor toughness of the prepared C / C-SiC composite material; figure 1 As shown, it is a schematic diagram of the interface reaction in the LSI process and the typical silicification damage morphology before and after the LSI reaction, indicating that the silicification damage of carbon fibers in the LSI process is more serious, which leads to lower mechanical properties; (2) in C / C-SiC composites , the micron-scale reinforcing phase of carbon fiber is difficult to toughen the micro-regions between carbon fiber bundles, within carbon fiber bundles, and between carbon fiber layers, resulting in the appearance of "weak areas" inside the material and reducing the comprehensive mechanical properties of the entire material; ( 3) During the long-term service of C / C-SiC composites, the fiber / matrix interface will experience interface wear and fiber strength decline due to interface debonding under long-term dynamic loads, resulting in material strength decline or even premature failure and fracture

However, the interfacial phase of carbon nanotubes can realize the toughening and interfacial strengthening of the internal micro-area of ​​the material, but this method cannot completely solve the corrosion damage of liquid silicon to carbon fibers.

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