Research progress on preparation and properties of zirconium carbide matrix composites

Zirconium carbide (ZrC) exhibits considerable potential for applications as aerospace thermal protection and the Generation-IV nuclear fuel inert materials due to its high melting point, exceptional hardness, good ablation resistance and low neutron absorption cross-section. Nevertheless, low sinterability of ZrC powders and poor fracture toughness and reliability of bulk ceramics limit their wide applications in extreme environments. This paper reviews the state of the art of preparation and properties of ZrC composites. Optimizing the sintering process and tailoring the chemical constituents of raw powders and sintering aids could improve sinterability to produce dense bulk ceramics. Different additives such as refractory metals, carbides, silicides, oxides, or carbon fibers are introduced into the ZrC matrix in order to improve fracture toughness, oxidation resistance or thermal shock resistance, etc. Further studies are needed to explore the effects of intrinsic defects (vacancies, dislocations, and grain or phase boundaries, etc.) and additives on microstructure and properties at elevated temperatures.