Grain Growth Kinetics of Cobalt-doped SnO_2 by Varying Nb_2O_5 Content

摘要

SnO_2 ceramics were co-doped with the aliovalent ions of CoO and Nb_2O_5 and the grain growth behavior of the SnO_2 was investigated. When only CoO was doped, the grain growth exponent of SnO_2 was 3. As the amount of Nb_2O_5 increased, the exponent changed from 3 to 2 when 0.505 mol% of Nb_2O_5 was added. The further addition of Nb_2O_5 changed the exponent from 2 to 3. When Nb_2O_5 content was 0.505 mol%, of which the grain growth exponent was 2, it is believed that an iso-electric point is formed without grain boundary segregation, since the respective space charges, generated by Nb~(5+) and Co~(3+) might compensate each other.