放電焼結における通電経路とモールド内部の温度分布

Abstract

In spark sintering copper powder and alumina one with a graphite and insulated dies under a constant pressure and a constant electric current, electric voltage between electrodes and temperature distributions of die, punch and specimen were measured. And, we considered effect of the electric current paths on the spark sintering.In the first case of sintering the copper powder with the graphite die, during initial electricity, almost all the electric current went through the specimen. During sequential electricity, the electric current went through both the graphite die and the specimen. Therefore, fluctuation of temperature distribution in the specimen was decreased as the discharged time was spent.In the second case of sintering the copper powder with the insulated die, the electric current went through the graphite punch and the specimen. The fluctuation of temperature distribution in the specimen was larger than that of the case which the graphite die was used, for the specimen was not heated by the graphite die.In the third case of sintering of alumina powder with the graphite die, the electric current went through the graphite punch and the graphite die. Therefore, the temperature distribution of both the graphite mold and the specimen was considerably different from that of the case of the copper powder with the graphite die.