Preventing hydrolysis of BaTiO3 powders during aqueous processing and of bulk ceramics after sintering

This present article addresses the reactive behaviour of barium titanate (BaTiO3, hereafter referred to as BT) with water either in powder form or as bulk ceramics. Chemisorbing a suitable phosphate-based protective agent at the surface of BT particles prevented hydrolysis reactions and made aqueous processing of BT a safe and viable route. Highly concentrated (50 vol.%) fluid and long term stable suspensions could be easily prepared from surface treated BT particles, contrasting with the poor stability and high viscosity of slurries derived from the as received powders. For aqueous suspensions, the course of hydrolysis reactions was monitored through changes in pH and concentrations of leached ionic species along ageing time. For bulk ceramics, the extent of hydrolysis reactions was assessed through the microstructural changes occurred at polished surfaces without and with surface treatment, which have been kept in contact with water for a certain time period.