Micromechanical analysis of effective properties of plasma sprayed alumina coatings

With the use of an image analysis technique, microstructure of plasma sprayed alumina coatings is quantitatively characterised using such parameters as the size, shape and number (density) of microvoids and the porosity level in the coatings. A Monte-Carlo simulation approach is proposed to model the characterised microstructure of alumina coatings with various levels of porosity. Based on this approach, effective elastic properties of the coatings with low porosity (less than 10%) are calculated using an analytical method. The effect of microstructure on material properties is investigated quantitatively and qualitatively. The numerical results are compared with the data obtained from nanoindentation and bending tests.