Critical Evaluation of Atmospheric Plasma Sprayed Deposition of Cu-based Coatings

The aggressive environment in which gas turbines operate subjects their components to degradation and shortens their service life. For example, the dovetail roots of compressor blades are subject to fretting wear due to the oscillatory motion that occurs at the interfaces of two contacting parts. Atmospheric plasma sprayed (APS) coatings are a common surface engineering technique due to their low cost of operation and efficient coating processing. Copper-based APS coatings are primarily used to prevent fretting wear on aerospace engine components. In particular, copper-nickel coatings have been shown to reduce fretting, galling and cavitation wear in gas turbine engines. Copper-nickel coatings also help reduce the coefficient of friction of titanium alloy parts. They are also used as an anti-fretting coating to protect the contact area of the dovetail part of the compressor blade root. The purpose of this study is to deposit copper-nickel on stainless steel, carbon steel, and aluminum substrates using APS to investigate the adhesion mechanism of the coatings and the substrate. The microstructural and mechanical properties of the coatings, as well as the tribological performance at different temperatures, were investigated for their suitability at the interfaces of the low temperature region of the gas turbine engines.