| 摘要 |
PURPOSE:To obtain cubic boron nitride ceramic material having high toughness by heating the green compact of the mixture of titanium hydride and cubic boron nitride powder in vacuum and allowing both to react with each other and treating a porous sintered body wherein titanium nitride and titanium boride are strongly bonded to cubic boron nitride at ultrahigh pressure and high temp. CONSTITUTION:The mixture of 0.5-20wt.% titanium hydride powder (TiHx, mean particle diameter is less than 1mum) and the balance cubic boron nitride powder (c-BN, mean particle diameter is 1-10mum) is molded into a green compact. Thereafter, this green compact is heated and held at 1200-500 deg.C in vacuum. TiHx is allowed to react with c-BN to produce TiN and TiB2. A porous c-BN- based ceramic sintered body having a structure is obtained wherein TiN and TiB2 are strongly bonded to c-BN. This sintered body is treated at the ultrahigh pressure and high temp. to make it dense at theoretical density ratio of at least 98%. Thereby the c-BN-based ceramic material having high toughness is obtained. |
