Ceramic matrix composite and preparation method and application thereof

Abstract

The invention discloses a ceramic matrix composite and a preparation method and application thereof, belongs to the technical field of ultra-high temperature ceramic matrix composites, and relates to a preparation method of a high-strength, high-toughness, high-density and fine-grain organization material. Zirconium diboride powder is used as a matrix phase, and zirconium disilicide powder is used as a sintering aid, so that the optimum sintering temperature, sintering pressure and sintering time of the ceramic matrix composite are lower than the requirements of the hot pressing sintering technology in the prior art; a multi-wall carbon nanotube is used as an additive for improving the internal organization structure of the ceramic matrix composite, obviously reduces the crystal grain size of the ceramic matrix composite, and improves the breaking tenacity of the ceramic matrix composite to 6.98 MPa.m<1 / 2>. The preparation method uses a two-step hot pressing sintering technology with fast and low-temperature characteristics to prepare the zirconium diboride ceramic matrix composite with high density and mechanical properties, and facilitates the subsequent large-scale production preparation and fiber toughening technology.

Description

technical field [0001] The invention belongs to the technical field of ultra-high temperature ceramic-based composite materials, and relates to a zirconium diboride ceramic-based composite material with high strength and high toughness and a preparation method thereof, in particular to low-temperature, rapid preparation of high-density, fine-grained A two-step hot-pressing sintering method for zirconium diboride matrix composites with crystal structure. Background technique [0002] In the field of aerospace technology, the "sound barrier" problem (flight speed > Mach 1) caused by the compressibility of air has been solved, and the Bell x-1 project launched by the National Advisory Committee for Aeronautics (NACA) has made the aircraft speed exceed 1 Mach is possible, which is inseparable from the emergence of thermal protection materials. Traditional thermal protection materials can basically meet the requirements of supersonic flight. However, the birth of the concept ...

AI Technical Summary

Problems solved by technology

This leads to high preparation cost and long preparation cycle, which brings difficulties to the subsequent large-scale production of zirconium diboride ceramic matrix composites.

[0004] In addition, the fracture toughness value of zirconium diboride with hard and brittle characteristics is 2.1-3.5 MPa m 1 / 2 , its sensitivity to cracks and brittle fracture mode will lead to catastrophic damage, which has become the main reason for limiting the wide application of zirconium diboride ceramic matrix composites in the field of thermal protection materials

In the past, the high sintering temperature and long sintering time made the grains of zirconium diboride material rough and large in grain size, and it was impossible to achieve fine grain toughening

The effect of self-toughening zirconium diboride ceramic matrix composites by preparing the interlocking structure of rod-like grains is not ideal, and it still shows a brittle fracture mode

It is generally believed that the most promising toughening method is to use silicon carbide fibers or carbon fibers to toughen zirconium diboride ceramic matrix composites, but the toughening effect is also severely limited. The most important reason is that when the sintering temperature is higher than 1700 ° C When the toughening phase is used, the decomposition and destruction of silicon carbide fiber or carbon fiber is very serious, and the expected toughening effect cannot be achieved.

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