Mechanical strengths of BaTiO₃ thick films after dielectric breakdown

Mechanical strengths of porous BaTiO₃ thick films were measured after dielectric breakdown, the bending stress was applied to the position where the electric field had been applied. Comparison of the Weibull plots of mechanical strength between electrically failed and unfailed (as-sintered) specimens has shown that no damage due to dielectric breakdown occurred and that the poling process naturally involved in the dielectric strength measurement increased the mechanical strength. Mechanical strength before dielectric breakdown was estimated by taking into account this strengthening effect which depended on the poling voltage, time and temperature. A clear correlation between mechanical and dielectric strengths was obtained with the correlation coefficient of 0.73.