SURFACE SEGREGATION AND EFFECT OF MECHANICAL-STRESS ON SB-STABILIZED TETRAGONAL ZIRCONIA

Compact pressure effects on Sb-doped tetragonal zirconia have been mon itored using XRD, Raman and FTIR spectroscopies. A martensitic tetrago nal-->monoclinic transformation, driven by compact pressure, has been observed upon pelletisation of stabilised samples. By contrast, no mon oclinic phase has been observed on amorphous powders upon pelletisatio n and firing. Sb surface segregation has been observed upon firing of pellets. The phenomenon has been quantitised by angle resolved XPS usi ng the recent Gries algorithms to evaluate the Zr 3d photoelectron ine lastic mean free path in ZrO2 which, in turn, compares well with previ ous experimental data. Surface Sb segregation occurs over a depth rang e and involves many ionic planes. An experimental estimate of the Sb s egregation enthalpy has been evaluated.