| 摘要 |
PURPOSE: To obtain boride ceramic having high hardness, high toughness and high strength, excellent in thermal shock resistance and useful as a wear resistant member, a tool material, a molten metal member, etc., by sintering powder starting material contg. boride of a specified element with plasma by electric discharge. CONSTITUTION: When powdery starting material contg. boride of a group IVa element of the Periodic Table is sintered to produce boride ceramics, the starting material is sintered with plasma by electric discharge to obtain the objective ceramic. In sintering with plasma by electric discharge, the activation of the surfaces of particles due to the generation of plasma by electric discharge, diffusion due to self-heating by electric discharge among particles and restraint on mass transfer as well as diffusion by heating and plastic fluidization by pressurization as sintering acceleration factors in hot pressing contribute to sintering. As a result, by sintering with plasma by electric discharge, densification is enabled at a low temp. in a short time and grain growth is suppressed. The objective boride ceramic having high hardness, high toughness and high strength and excellent in thermal shock resistance is obtd. by adopting sintering with plasma by electric discharge. |
