Mechanical Properties of Particulate Reinforced SiC-based Ceramic Composites

SiC based ceramics have excellent properties in strength, hardness and chemical stability at high temperatures. Such attractive characteristics make them promising condidates for high temperature structural or wear and corrosion-resistant materials. On the 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 compounds as a filler has been attempted. 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 compounds particles/SiC matrix composites exhibited improved mechanical properties compared to the monolithic SiC or the compounds. The electric conductivity of the composites can be varied by changing the amount of carbides, nitrides or borides of transition metals. Use of refractory compounds/SiC composites may solve two problems: low fracture toughness of ceramic materials and difficulty of machining them by using an electric discharge method.