The effect of Ti/Sr ratio on the grain growth of La-doped SrTiO3 ceramics sintered at 1400-1490°C for 2h in 5% H2-95% N2 with precisely controlled Ti/Sr ratio of 0.96-1.04 was investigated. The grain size was maximum at Ti/Sr ratio of 1.000 and remarkably decreased with excess amounts of Sr and Ti above 1470°C. However, the grain size was 2μm and almost constant below 1440°C regardless of the composition. The bulk density was almost constant (97%) in the Ti excess region, but decreased remarkably by addition of excess Sr. The microstructure was divided into three types depending on the Ti/Sr ratio and sintering temperature; (1) Sr rich region, (2) Ti/Sr≥1 and above 1470°C, (3) Ti/Sr≥1 and below 1440°C. In the early stage, the nuclei of remarkably grown grains were formed and their amount and the grain growth rate were dependent on the Ti/Sr ratios.
