Dynamic tribo-pair of PS400 and DLC for planet Venus application

Abstract

Abstract Bearing materials in future missions to Venus will encounter high temperatures (~462\xa0°C) and extremely dense CO2 atmosphere. Herein, we report on the tribological behavior of PS400 coating (NiMoAl-based alloy) vs. DLC coating at 25, 300, and 500\xa0°C under CO2 and air environments. We found that at 25\xa0°C DLC provides excellent lubrication and extreme wear resistance. At 300\xa0°C in CO2, oxygen-containing terminating groups passivated the dangling bonds of the graphitized DLC, and low friction was maintained. However, under air the friction increased significantly. At 500\xa0°C, DLC was worn out and PS400 transfer oxides alleviated the wear in both environments. The unworn and worn surfaces were analyzed using different analytical techniques.