Abstract
Sintered discs (1450 °C) of yttria-stabilised tetragonal zirconia (3 mol% Y 2O 3) with additions of 1, 10 and 20 mol% TiO 2, were treated in distilled water in an autoclave at 170 °C for times up to 144 h. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were used to monitor changes which occurred at the surface of the discs during autoclave treatment. The addition of TiO 2 retarded the transformation of the tetragonal (t)-phase to monoclinic (m)-phase as determined by XRD. During autoclave treatment an increase in the Ti Zr ratio, decrease in the Y Zr ratio and a peak in the percentage Zr 3+ were observed using XPS. Furthermore, at long autoclave treatment times there was a surface oxygen enrichment in excess of that expected from the stoichiometry. The data have been interpreted in terms of vacancy annealing and the rate of transformation to m-ZrO 2 appears to be related to the presence of Zr 3+, adsorbed water and substitutional cations such as Ti 4+ in modifying adsorption sites at the surface.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call