Effect of CeO2 and Al2O3 contents on Ce-ZrO2/Al2O3 composites

Effect of CeO2 and Al2O3 contents on phase composition, microstructures, and mechanical properties of Ce-ZrO2/Al2O3 composites was studied. The CeO2 content in CeO2-ZrO2 varied from 7 to 16 mol%, and the Al2O3 content in Ce-ZrO2/Al2O3 composites were 7 and 22 wt%. When CeO2 content was 10 mol%, high Al2O3 content contributed to hinder the tetragonal-to-monoclinic ZrO2 phase transformation during cooling and decrease the density of microcracks in the composites. Tetragonal ZrO2 single-phase was obtained in the composites with 12 mol% CeO2, regardless of the Al2O3 content. Hardness, flexural strength, and toughness were dependent on CeO2 and Al2O3 contents which were related to the microcracks, grain size, and phase transformation. The high flexural strength and toughness of the composites with 7wt% Al2O3 could be obtained at an optimum CeO2 content of 12 mol%, whereas those of the composites with 22 wt% Al2O3 could be achieved in the wide CeO2 content range of 8.5-12 mol%.