Correlation between mechanical properties and microstructure of phase transformation of zirconia ceramics by in high temperature and high pressure water environment

Abstract

High-temperature and high-pressure water corrosion behaviors of Y 2O3 doped Zirconia (ZrCh2) were investigated in term of with the microstructural changes, residual strength characteristics and tetragonal to monoclinic phase transformation. Sintered ZrO2 ceramics bodies with 2, 3, 4, 6 and 8mol% Y2O3 doped ZrO2 were made using a pressure less sintering method at 1 450°C, respectively. These ZtO2 ceramics were corroded in high-temperature and high-pressure water condition such as 150°C-300°C. Corrosion damage of the decrease Y2O3 dope ZrO2 ceramics occurred preferentially on ZrO2 particle after long-term immersion in high-temperature and high-pressure water environment. The tetragonal to monoclinic phase transformation occurred in decrease Y2O3 doped tetragonal ZrO2 ceramics due to high-temperature and high-pressure water corrosion. For improvement of the corrosion characteristics (thermal stability) of the ZrO2 ceramics, are important increasing the Y2O3 doped within a range in which no remarkable residual strength degradation is recognized. CeO2 doped ZrO 2 ceramics were useful to improvement the thermal stability of Y 2O3 doped ZrO2 without loss of the fracture strength. CeO2 doped ZrO2 ceramics also have superior residual strength characteristics compared to Y-ZrO2 ceramics. In addition design concepts used to obtain water- corrosion-resistant high strength and high toughness ZrO2 ceramics were proposed.