ON THE CORRELATION BETWEEN MECHANICAL DAMAGE AND THE ELECTRICAL-PROPERTIES OF ZIRCONIA CERAMICS

This paper refers directly to a previous investigation, where Vickers indentations of different loads were applied to a YSZ-zirconia and the n impedance spectroscopic parameters were measured in dependence on th e indentation load. The aim of the present paper was to find a correla tion between the impedance spectroscopic parameters and mechanical dam age, e.g. microcracks. Stress intensity factors, K(c), were evaluated by the ICL (indentation crack length) and ISB (indentation strength in bending) methods, to characterize the material mechanically, and were compared to K(c) from conventional bending experiments with notched s pecimens. By SEM investigations of the as-indented surfaces and of the fracture surfaces after breaking open the specimens, the radial/media n and the lateral crack systems were investigated. The observed crack systems could be correlated to the impedance spectroscopic parameters given in Ref. 1 and it is demonstrated that it is possible to characte rize microcracks in ionic ceramics by impedance spectroscopy.