Nanoindentation investigation of mechanical properties of ZrO2, ZrO2–Y2O3, Al2O3 and TiO2 thin films deposited on stainless steel OC 404 substrate by spray pyrolysis

Thin ZrO2, ZrO2–Y2O3, Al2O3 and TiO2 films were deposited by spray pyrolysis method on stainless steel OC 404 substrate with thickness 50 μm. The thicknesses of obtained films varied from 0.50 to 0.64 μm. The surface morphology and structure of the films were characterized by scanning electron microscopy in secondary electron imaging mode. The X-ray diffraction measurements for determination of the lattice parameters, the average crystallite size and the sample strain were performed. Mechanical properties of investigated films and substrate were investigated by nanoindentation experiments, using Nano Indenter G200 (Agilent Technologies). As a result of nanoindentation experiments, load–displacement curves were obtained and two mechanical characteristics of the substrate and investigated films – indentation hardness (HIT) and indentation modulus (EIT) – were calculated using Oliver & Pharr approximation method. Dependence of indentation modulus and indentation hardness on depth of indentation was investigated as well.