Influence of steam-rich environments on the high temperature tribological behavior of Inconel 718 for sustainable aviation

The aerospace industry has been looking for solutions to minimize emissions of pollutants into the environment. In this direction, replacing fossil fuels is a promising strategy. The use of hydrogen as a fuel has been shown to be a promising alternative due to its cleaner combustion, with the potential to reduce harmful emissions. Hydrogen primarily produces water during combustion, which becomes steam at high temperatures inside a gas turbine engine. However, there is limited research on the behavior of nickel-based alloys, which are widely used in gas turbine engines, in hydrogen and steam-rich environments. The interactions between steam at tribological interfaces within these engines remain poorly studied. Therefore, this study investigates the high temperature tribological behavior of Inconel 718 under steam conditions. Experiments were conducted to understand the wear mechanisms and the effects of temperature and steam on Inconel 718, using an experimental setup for producing and applying superheated steam to the samples during the sliding test. Subsequent analyses were conducted with a 3D measuring laser microscope, scanning electron microscopy (SEM) and Raman spectroscopy. The results revealed that the coefficient of friction decreases with increasing temperature, while wear increases with temperature. Additionally, the presence of steam exhibited a mild influence on wear and friction characteristics.