Hydrothermal ageing of tetragonal zirconia porous membranes: Effect of thermal residual stresses on the phase stability. (September 2018) - Guo, Fangwei
Graphical abstract: Highlights: It is the first time to clarify the hydrothermal ageing mechanism of highly porous zirconia membranes. Monoclinic phase grains dispersed in the whole membranes. Highest monoclinic phase amount occurred at the interface transition regions. Asymmetric microstructure and porosity gradient led to residual stress after sintering. The thermal residual stress triggers the monoclinic phase growth. Abstract: Yttria-stabilized tetragonal zirconia hollow fiber membranes were aged in aqueous solution for investigating effect of porosity and residual stress on hydrothermal ageing. The monoclinic phase was evaluated by XRD and confocal micro-Raman spectra, to be ≤ 5.0 vol% and ≤ 60 vol% even after 100 h ageing, respectively. It is the first time to clarify the hydrothermal ageing mechanism of highly porous zirconia membranes. Highest monoclinic phase amount occurred at the interface transition regions of the aged samples, which suggested that the thermal residual stress can noticeably promote the monoclinic phase growth rate of the grain boundaries.