Mechanical and electrical properties of electronic ceramics under high stress condition and microstructures

Mechanical properties of several kinds of electronic ceramics were investigated. Compression tests were carried out until the mechanical failure took place. Then, the ultimate breaking strengths were compared among the various electronic ceramics investigated. The changes of piezoelectric properties in the piezoelectric ceramics subjected to increasing compression load were measured. The fracture surface was observed with scanning electron microscopy. The rectangular alumina plate samples were fired at the temperature range of 1480-1660 degrees C in the dimensions of 10-mm width, 50-mm length and 0.8-mm thickness. The static tension test was performed with a specimen geometry devised to prevent fracture at the gripping portion. Statistical analysis based on a two-parameter Weibull distribution revealed that the dispersion of tensile strength was comparatively small when using the present specimen geometry, and the samples fired at 1540 degrees C showed a maximum tensile strength. These results are discussed from the viewpoint of the microstructure.<
>