Formation, Microstructure, and Properties of Barium Zirconium Sulfide Ceramics

The preparation, microstructure, and properties of BaZrS₃ ceramics are described. The compound was prepared by heating either an equimolar mixture of BaS and ZrS₂ or BaZrO₃ alone in CS₂ gas. The reaction of the BaZrO₃−CS₂ system was extremely rapid, as would be expected in an autocatalytic reaction caused by very strong reduction by CS₂. Well-sintered bodies were obtained only by the BaZrO₃−CS₂ reaction. The time dependence of grain growth was affected considerably when reaction and sintering occurred above 1250° C. Non-uniform grain growth which occurs when an excess of Ba is present can be interpreted in terms of secondary recrystallization resulting from segregation of BaS at the grain boundary during sintering. The BaZrS₃ ceramic was stable in air up to 550°C and was oxidized above that temperature.