Study of Microstructure and Mechanical Properties of Yttrium Stabilized Zirconia Coating Deposited by Air Plasma Spray

Abstract

Ceramic materials have been used extensively in different industries due to their excellent properties in high temperature environment. Thermally sprayed ceramic coatings offer outstanding properties which make them suitable candidate for advanced applications. These coatings exhibit excellent wear resistant properties with high adhesion strength. Depending on the application, ceramic coatings can be subjected to in-plane or out-of-plane loading during service. When the components are exposed to extreme change in temperature, consistent expansion, and shrinkage of the materials will cause crack initiation and propagation, resulting in spallation of the coating and consequently failure of the components. In this study, mechanical performance of plasma sprayed Yttrium stabilized Zirconia coating was investigated. A powder mixture of Yttrium stabilized Zirconia (ZrO2−8Y2O3) was air plasma sprayed on a cast iron substrate. Microstructural characterization of the as-sprayed coating was performed to evaluate the microstructural uniformity of the deposited samples using scanning electron microscopy (SEM). Three-point bend tests were performed to measure bending modulus of the free standing as-sprayed coating samples. Knoop indentation technique was also used as an alternate method to determine the modulus of the coating. Damping properties of the samples were also evaluated. This study pays special attention to the dependency of the mechanical performance on the microstructural characteristics of the thermal sprayed ceramic coatings.