Control of impurity phases in La-doped SrTiO₃ synthesized by citric-gel method

Abstract

La3+-Doped strontium titanates are reported to be one of candidate materials for interconnects of SOFCs. A high temperature heat-treatment is required to obtain firing density of the compacts more than 94% as the interconnect. Soft-chemical techniques such as a citric-gel method are often applied to promote the densification because powders obtained are very fine. However some RP (Ruddlesden-Popper) phases as the second phase appeared in the La-SrTiO3 samples even after fired 1600C. In this study, we chose TAS-FINE and TTIP as titanium sources for the citric-gel method, and the effect of the difference of starting materials on appearance of RP phases was examined.