Abstract
During the past few years thermally sprayed ceramic coatings deposited from nanostructured feedstock powder have often demonstrated improved properties relative to coatings produced from convention powder. Nanostructured or bimodal structured ceramic coatings have been reported to exhibit better wear resistance and adhesion strength. For thermal barrier coatings, key properties include thermal conductivity and thermal stability. In this study thermomechanical properties of plasma sprayed, bimodal structured, yttria stabilized zirconia coatings were investigated. The thermal stability was examined by measuring the hardness and elastic modulus of free standing coating layers before and after heat treatments in air at 600-800 °C. The creep behaviour was investigated using free standing coating layers loaded in the four point bending configuration at temperatures of 1000 °C in air. The results for bimodal structured coatings have been compared with the behaviour of conventional plasma spray coatings under the same test conditions.
