Preparation and tribological properties of different kinds of metal foam-polytetrafluoroethylene co-continuous phase composites

Co-continuous phase composites of polytetrafluoroethylene (PTFE) interpenetrated with five kinds of open-cell metal foams, Cu, Ni, Fe, CuNi and FeNi, were prepared via emulsion impregnation, vacuum impregnation and free sintering. The microstructure, mechanical performance, thermal stability and tribological behavior characteristics of these materials were investigated. The results showed that the filling efficiency of PTFE was between 76.1% and 98.7%. The developed composites generally exhibited enhanced strength and thermal stability. In particular, their wear rate under dry friction conditions was reduced by 63-95% compared with pure PTFE resin, which was ascribed to the effective transfer of friction heat and the enhanced load bearing capacity. However, their tribological performance weakened in a simulated seawater environment because of the diffusion of seawater in the materials and corrosion of the metal skeletons.