超硬質セラミックス材料の創製と評価

抄録

Superhard ceramic materials such as diamond, cubic boron nitride and high-boron compounds are known to have a Vickers microhardness above 30 GPa and are expected to be applied to various kinds of cutting tools, molds or protective coatings. However, these materials are very difficult to form and sinter on account of their strong covalent bonding and the low diffusivity of their constituents in solids even at elevated temperatures. Therefore, special consolidation techniques are required to prepare bulk bodies or coatings of these materials. In the present paper, a series of the author's previous works on the preparation of superhard ceramic materials by chemical vapor deposition and high-pressure sintering are reviewed, and the mechanical and chemical/thermal properties are described and discussed in relation to their microstructures.