抄録
Microstructures of ZrO2–CeO2 ceramics were investigated with arc-melted specimens by means of TEM, TEM-EDX, ED. and XRD. Results obtained are as follows. (1) As-cast specimens with more than 15 mol% CeO2 consisted of a relatively stable cubic phase having super sub-lattice of O2− ions. The reciprocal lattice was obtained. (2) By annealing the cubic phase in air, the super structure disappeared, and the transition from cubic to tetragonal phases easily took place. (3) During prolonged annealing a nucleation-growth type coherent precipitation took place. (4) Phase boundaries of the cubic and tetragonal phases in the diagram of the ZrO2–CeO2 system were determined. (5) Sintered 12 mol% CeO2 specimen consisted of the tetragonal phase. This phase resisted to a long time annealing, but was transformed easily into the monoclinic phase by pulverizing.
