Boride Ceramics: Densification, Microstructure Tailoring and Properties Improvement

Borides,including TiB2,ZrB2,HfB2,B4C and BN,have good physical and chemical properties,which have been proposed for a variety of applications in extreme environments,such as ultra-high temperature,super-hard and super-hydrophobic.However,the engineering applications of these borides are still restricted by their poor sinterability and unsatisfied material properties including low fracture toughness.In regard with the advantages of pressureless sintering in preparation of ceramics,the main factors that affect the pressureless sintering of borides are discussed.The pressureless sintering technology of borides represented by oxygen removing mechanism is summarized.In consideration of the low toughness of borides,the microstructure tailoring methods represented by platelet toughening and nano phase reinforced are emphasized.At last,the methods for preparing textured boride ceramics are also briefly introduced.