Mechanical Properties of Particulate Reinforced SiC-based Ceramic Composites

Abstract

SiC based ceramics have excellent properties in strength, hardness and chemical stability at high tempertures. Such attractive characteristics makethem promising candidates for high temperature structural or wear and corrosion-resistant materials. Onthe other hand, carbides, nitrides or borides of transition metals, such as TiC, NbC, ZrC, TiN, TiB2 and ZrB2, have prominent refractriness with good electric conductivity. Sintered SiC and refractory compounds,however, have low fracture toughness. In order to improve the fracture toughness of ceramic materials, use of refractory compoundsas a filler has beenattempted. In this article fabrication and mechano-physical properties of SiC-X (X; carbides, nitrides or borides of transition metals) composites and their microstructure-macro properties relation are reviewed. Refractory compoundsparticleslSiC matrix composites exhibited improved mechanical properties comparedto the monolithic SiC or the compounds.The electric conductivity of the composites can be varied by changing the amountof carbides, nitrides or borides of transition metals. Useof refractory compoundslSiCcomposites maysolve two problems: Iow frac~ure toughness of ceramic materials and difficulty of machining them by using an electric discharge method. © 1992, The Iron and Steel Institute of Japan. All rights reserved.