Abstract
Cavitation erosion is a mass loss process that occurs in a component subject to a liquid pressure variation. The mass loss phenomena occurred by extensive microstructure deformation with combination of shock loading and fatigue caused by the impact and collapse of the bubbles at surface. Many studies have been done to evaluate the cavitation resistance of the thermally sprayed coatings. Oxide formation, microstructure and tensile adhesion are important characteristics for coatings against cavitation. In this work some Fe-Mn-Cr-Si alloys, that is a class of steel with strain induced phase transformation, were used to evaluate the chemical composition influence on the microstructure, oxide formation, chemical composition and tensile adhesion of HVOF coatings. It was observed a significant reduction on the porosity, from 3% to 0,1%, and area fraction oxide from 15% to 7%, with Boron and Nickel addition. A combination of Nickel and Boron addition improve the wettability of the splats with increase on the tensile adhesion of the coatings, up to 60MPa, otherwise, higher levels of Boron content reduce the adhesion of the coatings.
