Engineering of lightweight ceramic composites by spark plasma sintering

It is well recognised that value of porosity and grain size influences mechanical properties such as fracture toughness, elastic modulus and strength dramatically. Boron carbide (B4C), as well as other lightweight ceramics like TiB2, B6O requires high consolidation temperatures owing to its poor sinterability. Therefore such decrease of ceramics properties becomes a materials processing issue since during consolidation process on the final stage of sintering (either pressure-assisted or pressureless one) grain growth starts. To overcome this problem, various metallic and non-metallic binders are used to obtain dense borides. However, the presence of a metallic binder is not desirable for high-temperature structural applications. We propose that reaction-driven consolidation by means of spark plasma sintering (SPS) at temperatures exceeding 1800 °C as an alternative method for fabrication of high-temperature lightweight ceramic composites. This work summarizes recent activity on processing of lightweight ceramics based on boron carbide, boron suboxide and titanium diboride in the respect to mechanical properties: such as hardness, fracture toughness and room and high-temperature strength. Application of various techniques for powders preparation and consolidation by SPS is thoroughly discussed in respect to obtained lightweight ceramic composites properties. A thorough discussion of high-temperature properties for these ceramic composites is also provided