Development of tribologically optimized surface coatings with micro and nano particles

This paper is focused on the tribological behaviour of epoxy-based coatings applied to metal substrates. Aramid particles, nanometer-sized Titanium dioxide (TiO2), graphite and Polytetrafluoroethylene (PTFE) served as filler materials. Under sliding conditions, incorporation of Aramid particles to the graphite and TiO2 filled composites improved the wear resistance significantly, but it slightly increased the coefficient of friction (cof). Under fretting wear conditions, 10 vol.% Aramid particles filled composite showed the lowest wear rate and cof. To further improve the wear performance, PTFE (2 - 6 vol.%) was introduced to the above-optimized composition (10 vol.% Aramid particles, graphite and TiO2). However, both the sliding and fretting wear resistance was impaired, and cof was increased. Deterioration of the mechanical properties and the friction films were attributed to the unusual trend. Finally, the optimal composition for epoxy-based coatings was determined as 10 vol.% Aramid particles together with graphite and nano-TiO2 filled composite.