The influence of the internal current for the ZnO ceramics on the sintering behavior by pulse current sintering (PCS) method was investigated. The electric resistance of the sintering ZnO ceramics drastically decreases by the addition of the small Al2O3, and it is expected that a part of sintering current flows in the specimen and affects the sintering behavior of the ZnO ceramics on the PCS method. To clear the dependence of inner current on the sintering behavior of ZnO ceramics, direct measurement of electric resistance of ZnO specimen under sintering by SPS device was carried out. It was observed that electric resistance of specimen decreases with increase in the temperature. The electric resistance begins to decrease from the low temperature of 200°C. The internal structure of sintered ZnO ceramics changed by the control of the internal current in the specimen using Al2O3 plate.
