Method of surface strengthening alumina-zirconia composites using MoO.sub.2

Abstract

MoO.sub.2 is used as an accelerant for transformation of zirconia (ZrO.sub.2) from a tetragonal to a monoclinic crystal phase. A ZrO.sub.2 -MoO.sub.2 alloy having an increased content of monoclinic ZrO.sub.2 is prepared by mixing MoO.sub.2 with ZrO.sub.2 followed by heat treatment. In another aspect of the invention, the surface of an alumina-zirconia composite is strengthened by heating the composite in the presence of MoO.sub.2 -ZrO.sub.2 mixed powder.