Insights of the Ultralow Wear and Low Friction of Carbon Fiber Reinforced PTFE in Inert Trace Moisture Environment

Abstract Ultralow wear rates and low friction have been observed for carbon fiber reinforced PTFE (CF/PTFE) when sliding against steel or cast iron in dry gas environments. Although the strong environmental sensitivity of this tribosystem is well known, origin outstanding tribological performance remains unanswered. Some researchers attribute to formation carbon-rich surfaces absence oxygen moisture environment. However, between generally dependent on moisture. In paper, extensive analyzes are conducted tribofilms formed CF/PTFE surface counterface after a high-purity nitrogen TEM analysis cross-section tribofilm reveals that consists mainly (II) fluoride not carbon, even though significant amount was near surface. XPS further revealed worn composite consisted nanoparticle agglomerates, anchored matrix each other by with turbostratic structure. Turbostratic also an ultrathin surface-oriented superficial layer top agglomerates. Governing mechanisms CF/PTFE—steel were investigated complementary tribotests pure graphite samples MD simulations identified surfaces. These indicated due poor adhesion distinctly different Graphical