Processing of 0.7BaTiO3-0.3BiScO3 Solid-Solution Coatings

Coatings with the 0.7BaTiO3–0.3BiScO3 solid‐solution composition were formed on palladium and single‐crystal (001) SrTiO3 substrates using a polymeric metal citrate precursor. Solutions of TiOCl2, Ba(NO3)2, Sc(NO3)3, and Bi(NO3)3 were mixed with citric acid and polymerized with ethylene glycol. Stable mixed‐metal citrate solutions were formed at pH > 9 and used for coatings. The phase and composition of powders and coatings were characterized using DTA, TGA, SEM, TEM, and X‐ray diffraction. Single‐phase cubic 0.7BaTiO3–0.3BiScO3 solid solutions formed at 600°C. Coatings on Pd using precursors doped with 5 wt% lithium nitrate were dense after sintering at 950°C/1 h. Coatings without lithium nitrate required 1050°C/50 h to densify. Coatings on SrTiO3 heat‐treated at 1150°C were dense but formed a (Sc,Ti)‐rich second phase.