| 摘要 |
PROBLEM TO BE SOLVED: To provide a sintered body of the uniform structure and characteristic by energizing the surface in which the powder material is brought into contact with a forming die and/or punch through an electric insulation layer to eliminate formation of a degraded layer in a surface layer part of the sintered body. SOLUTION: Electric insulation layers 4, 5 which are formed by applying the powder of the electric insulation material in a sprayed condition are interposed at least on the contact part of a forming die 1 with the powder material M, and the surfaces of punches 2, 3 in contact with the powder material M. The electric insulation material includes, for example, boron nitride having the heat resistant characteristic capable of withstanding the energization sintering temperature of the powder material M. The micro discharge to be generated on the contact surface of the powder material M with the forming die is eliminated, or sufficiently reduced to avoid generation of the high temperature region. Formation of a degraded layer with different structure and characteristic from those of the inside the surface layer part of the obtained sintered body can be avoided. |
