Grain‐Boundary Phase Transformations During Aging of a Partially Stabilized ZrO ₂ ‐ A Liquid‐Phase Analogue of Diffusion‐Induced Grain‐Boundary Migration (DIGM)(?)

Abstract

The microchemical/microstructural evolution of grain‐boundary regions in a ternary (Ca, Mg)‐partially‐stabilized ZrO 2 during aging at 1400°C has been studied by transmission electron microscopy. Two distinct grain‐boundary transformation products, both of which involve single‐phase cubic (c)‐ZrO 2 zones adjacent to grain boundaries, have been identified. An amorphous silicate grain‐boundary phase, whose composition changes during aging, is also present. One of the two grain‐boundary reactions involves grain‐boundary migration by a solution/reprecipitation process and can be termed reactive film migration; it may be a liquid‐phase analogue of diffusion‐induced grain‐boundary migration.