TETRAGONAL ZrO₂-Y₂O₃ PART II : THE MECHANICAL AND ELECTRICAL PROPERTIES

Abstract

Dense tetragonal zirconia-yttria ceramics has been prepared with grain sizes between 0.1 and 0.5 µm. The fracture toughness and flexure strength at room temperature are independent on grain size and composition in the tetragonal phase region with YO1.5 larger than 5 at.%. The ageing rate of the mechanical properties increases with increasing grain size, but for samples with grains of 0.1 um no ageing is observed. The bulk and grain boundary resistivities are 1.5-2 times higher than in cubic materials. A low impurity level decreases the grain boundary resistivity while the bulk resistivity is hardly affected