Influence of Ce3+/Ce4+ ratio on phase stability and residual stress field in ceria-yttria stabilized zirconia plasma-sprayed coatings

CeO2-Y2O3 stabilized zirconia plasma-sprayed coatings have been produced by two different procedures based on different cooling rates. A high cooling rate (HCR) induced the contemporary presence of CeO2 and Ce2O3, while cooling in calm air (LCR) induced the presence of only CeO2. After subjecting the HCR coating, detached from the substrate, to an air thermal treatment, which oxidizes Ce2O3 to CeO2, a lower thermal expansion coefficient was measured than in the LCR material, and shrinkage was also observed. This behaviour is explained by the phase composition changes induced by the oxidation of ceria.