EFFECT OF A CHEMICALLY AGGRESSIVE ENVIRONMENT ON THE ELECTROMECHANICAL BEHAVIOR OF MODIFIED LEAD TITANATE CERAMICS

Modified lead titanate ceramics were fabricated under different sinter ing conditions, and the dielectric and piezoelectric properties of cer amics were determined for samples before and after immersion in water. Significant differences in these values were obtained for individual materials. Samples modified with both La and Sm did not exhibit any no ticeable degradation in properties whereas, in contrast, the samples c ontaining only La as a modifier showed severe degradation. This is par ticularly evident when comparing those samples sintered at 1280 degree s C. The stability of dielectric and piezoelectric properties of La an d Sm modified lead titanate after water treatment is explained by the high mechanical strength and chemical resistance to water of its grain boundaries.