Mechanical and tribological characteristics of Cu-based coatings applied using solid-state deposition techniques

Cu-based thermal sprayed coatings are commonly employed in critical parts within gas turbine engines. These coatings are typically deposited by traditional thermal spray techniques such as APS and HVOF, which can result in high oxidation within the coating. With the recent advancements in solid-state deposition processes, these techniques have become attractive for depositing such Cu-based coatings with the main purpose of decreasing the oxygen content. Thus, the main purpose of this study is to critically evaluate Cu-based coatings deposited by solid-state deposition processes (i.e., HVAF and CS) in terms of their tribological behaviour. The quantity of oxygen in the coating for the HVOF was compared with HVAF/CS processes. Optical microscopy and scanning electron microscopy (SEM) were carried out to determine the microstructure of the coatings. Furthermore, wear tests utilising a ball-on-disk tribometer and microhardness were conducted to define the tribological behaviour and mechanical properties of the generated coatings. The friction and wear behavior correlated to the oxidation level and interfacial processes identified through the ex-situ analysis.