High-temperature tribological performance of chromium oxide – NiMoAl based coating applied by atmospheric plasma spray

As the aerospace industry advances to meet new regulations, the operating conditions inside gas turbine engines become increasingly demanding. Consequently, next-generation aircraft components require development and testing of advanced materials. Thermally sprayed coatings are commonly used to improve wear resistance, with different approaches depending on the operating conditions. Varying temperatures and contact pressures are encountered within these turbines, making the precise definition of applied solutions critical for a smooth engine operation. The recent development of chromium oxide – NiMoAl based coatings, which offers exceptional strength, creep resistance, and oxidation stability, shows to be a promising material for these extreme aerospace conditions. However, limited tests were performed under extreme conditions. Therefore, this study focuses on the high-temperature tribological performance of chromium oxide – NiMoAl based coatings applied using atmospheric plasma spray (APS). Different thicknesses were sprayed and tested using a reciprocating flat-on-flat tribometer configuration. Relevant sliding distances and temperatures were selected for testing against Waspaloy flat counterfaces. In addition, different surface finishes were used to simulate the conditions that these surfaces are exposed to. Differences as a function of the coating thickness, initial roughness, and temperature have been assessed.