Mechanical Properties of Ce-ZrO2/Y-ZrO2 Composites
Takahiro KUDOU, Takayuki MURAKAMI and Atsushi NAKAHIRA
Abstract:In order to improve the strength, fracture toughness and thermal stability of 12Ce-ZrO2 ceramics, Zirconia composites consisting of 12Ce-ZrO2 and 3Y-ZrO2 were fabricated by normal sintering at 1450Ž and post HIP treatment at 1350Ž. Some mechanical properties were evaluated for these composites. The bending strength and fracture toughness were measured by three-point bending test and indentation fracture (IF) method, respectively. The microstructures of the composites were characterized by SEM observations and TEM-EDS analysis. The phase stability in these composites were also evaluated by hydrothermal aging test at 150Ž and 0.48 MPa. The addition of Y-ZrO2 into Ce-ZrO2 suppressed grain growth of 12Ce-ZrO2 matrix and improve the mechanical properties of 12Ce?ZrO2. Ce-ZrO2/Y-ZrO2 composites exhibited higher bending strength above 1000 MPa and higher fracture toughness above 8 MPaEm1/2 in the composition region of 80-90 wt% 12Ce-ZrO2. The tetragonal ¨ monoclinic phase transformation under hydrothermal conditions was inhibited in this composition region. It was found that the distribution of CeO2 / Y2O3 in the ZrO2 matrix has a great influence on the mechanical properties and phase stability. Key Words:Key words : Zirconia, Ce-ZrO2/Y-ZrO2 composites, Bending strength, Fracture toughness, Hydrothermal aging, Phase transformation