Effect of internal Stress on the Strength of PZT Cermics

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J. Korean Ceram. Soc. > Volume 33(1); 1996 > Article

Journal of the Korean Ceramic Society 1996;33(1): 49.

PZT 세라믹스의 강도에 미치는 내부응력의 영향

태원필, 윤여범, 김송희

강원대학교 재료공학과

Effect of internal Stress on the Strength of PZT Cermics

ABSTRACT

The aim of this study is to investigate the change of bending strength and fatigue strength in the unpoled and poled Pb(Zr, Ti)O3 ferroelectrics of tetragonal morphotropic phase boundary (MPM) and rhombohedral com-position in terms of internal stress which is measured by XRD method. Before poling treatment the highest bending strength was found in rhombohedral composition. After poling treatment the bending strength decreas-ed in all compositions but it decreased most remarkably in tetragonal composition. The most prominent de-crease of bending strength after poling treatment in tetragonal was attributed to the occurrence of microcracks due to highanisotropic internal stress around grain boundary which was induced of bending strength after poling in MPB and rhombohedral composition was not due to the occurrence of microcracks but to the increase in tensile internal stress perpendicular to the direction of crack propagation by domain alignment. Fatigue strength was higher before poling treatment than after poling treatment for various compositions.

Key words: Internal stress, Bending strength, Fatigue strength Poling treatment