LOW-TEMPERATURE AQUEOUS PREPARATION OF BARIUM METATITANATE POWDERS

Submicron BaTiO3 powders have been prepared at 85-degrees-C under atmo spheric pressure starting from TiCl4 and Ba(OH)2 in NaOH aqueous solut ion. Characterisation by BET, thermal analysis, differential dilatomet ry, X-ray diffraction and SEM/TEM microscopy has been performed. The p owders, with high specific surface area, show a cubic lattice and a qu asi-spherical morphology. A slight deviation from stoichiometry and a low level of residual carbonate have also been observed Sintering test s on isostatically pressed samples without binders have been carried o ut. A 15 h thermal treatment at 950-degrees-C upon firing results in i mproved final density (almost-equal-to 96% of the theoretical density) and in very fine grain size (1.1 mum). Washing with dilute (0.1 m) ac etic or hydrochloric acid to eliminate BaCO3 is detrimental to a high final density and gives rise to polytitanate formation.