2016 年 124 巻 9 号 p. 932-937
Tantalum oxide-doped, nano-sized tin oxide powder was consolidated by spark plasma sintering by systematically varying the sintering temperature, heating rate, holding time at the sintering temperature, and doping amount. The relative densities of the TaO2.5-doped SnO2 sintered specimens increased with the increasing sintering temperature from 800 to 1000°C, but were almost independent of the heating rate and holding time in the ranges from 30–90°C/min and 5–120 min, respectively. The DC electrical conductivity, in contrast, reached a maximum value at the sintering temperature of 900°C, but decreased at 1000°C due to decomposition of the SnO2. In addition, a faster heating rate and shorter holding time resulted in a higher electrical conductivity of the TaO2.5-doped SnO2 specimens due to the solution of Ta5+ in the SnO2 and formation of a metastable compound.