Influence of stress and chemical homogeneity on dielectric properties of BaTi0.9Zr0.1O3

The influence of mechanical stress and chemical homogeneity on the permitti vity of BaTi0.9Zr0.1O3 ceramics prepared from mixed-oxide and hydrothermal powders was studied. To reduce stress, liquid-phase sintering was applied i n conjunction with a low heating rate to stimulate the formation of large g rains. The influence of chemical homogeneity was studied by variations in s intering temperatures and times. For both types of ceramics, the dielectric constant at the Curie temperature was influenced by both factors, but to a different extent. In the mixed oxide ceramic, chemical homogeneity played a more prominent role, while internal stress appeared to exert a larger inf luence in the hydrothermal ceramics, The dielectric constant at the Curie t emperature could be increased by 5%-10% by an annealing treatment at 200 de grees C, followed by slow cooling.