Lubrication mechanism of PTFE on iron-based tribopairs in liquid oxygen under various loads: A reactive molecular dynamics study

This study systematically investigated the interfacial lubrication mechanism of polytetrafluoroethylene (PTFE) under various loads in a liquid oxygen (LO₂) environment using reactive molecular dynamics simulations. The results demonstrate that LO₂ forms a lubricating protective layer at the friction interface, thereby effectively reducing interfacial adhesion and friction. Furthermore, the introduction of LO₂ reduces the temperature of the tribological pair, improves the shear stress distribution, inhibits crystal structure damage, and significantly enhances the diffusion capability of PTFE molecules. Notably, the most significant improvement in lubrication performance due to LO₂ is observed at a low load of 0.7 GPa, with an average friction reduction of 74.23%.