Effect of sintering temperature on the microstructure and mechanical properties of ZrO2-3 mol%Y2O3 sol–gel films

The microstructural evolution and mechanical properties of ZrO2-3 mol%Y2O3 films were investigated as a function of the sintering temperature in the range from 100 °C to 1500 °C, using a battery of characterization techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and nanoindentation. It was found that the crystallization occurs at temperatures close to 300 °C. A gradual increase in the grain and crystallite sizes is observed as the sintering temperature increases up to 1000 °C, and above this sintering temperature the tendency changes abruptly with a rapid increase in these values. Although Young's modulus of the coatings did not change with sintering temperature, a slight decrease was observed in the hardness values above 1000 °C which is attributed to microstructure coarsening. Finally, a slight degradation of the films occurs above 1300 °C, which is due to the occurrence of a process of grain spheroidization.