In situ characterization of the grain and grain-boundary electrical responses of zirconia ceramics under uniaxial compressive stresses

The electrical properties of ion-conducting tetragonal zirconia ceramics subjected to mechanical stresses were studied using impedance spectroscopy. The material's overall resistance (grain and grain boundary) was found to increase when stress was applied perpendicularly to the measuring electric field (sigmaperpendicular toE), while only comparatively discreet variations, involving a decreasing trend of resistance, occurred when the electric field and mechanical stress were parallel (sigmaparallel toE). The increment in electrical resistance for sigmaperpendicular toE was found to be consistent with an increase of the conduction process energy barrier. The mechanical effect reported here is of elastic nature, covering a wide range of applied stresses. The electrical characteristics from cracking and fracturing at higher stresses are also presented. (C) 2002 American Institute of Physics.