Processing of 0.7BaTiO sub(3)-0.3BiScO sub(3) Solid-Solution Coatings

Coatings with the 0.7BaTiO sub(3)-0.3BiScO sub(3) solid-solution composition were formed on palladium and single-crystal (001) SrTiO sub(3) substrates using a polymeric metal citrate precursor. Solutions of TiOCl sub(2), Ba(NO sub(3)) sub(2), Sc(NO sub(3)) sub(3), and Bi(NO sub(3)) sub(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 0.7BaTiO sub(3)-0.3BiScO sub(3) solid solutions formed at 600 degree C. Coatings on Pd using precursors doped with 5 wt% lithium nitrate were dense after sintering at 950 degree C/1 h. Coatings without lithium nitrate required 1050 degree C/50 h to densify. Coatings on SrTiO sub(3) heat-treated at 1150 degree C were dense but formed a (Sc,Ti)-rich second phase.