Tribological behaviors of binary and ternary epoxy composites functionalized with different microcapsules and reinforced by short carbon fibers

The effects of compositional modifications on the sliding friction and wear against bearing steel were investigated for newly-developed binary and ternary epoxy composites. Some of the new materials included hexamethylene diisocyanate (HDI) filled microcapsules and wax filled microcapsules, and others used HDI filled microcapsules, wax filled microcapsules and short carbon fibers (SCFs) at different ratios. The hardness of the binary and ternary epoxy composites decreased with increased content of wax filled microcapsules. The wax filled microcapsules were larger than the HDI filled microcapsules. Due to the rigidity of the SCFs, the hardness of the epoxy composites with 8 wt% SCFs was higher than that of the composites without SCFs. Pin-on-disc, sliding friction and wear performance for the binary and ternary epoxy composites tested against a 100Cr6 steel ball, were improved as the content of wax filled microcapsules increased. This was due to their effective lubricating effects. It was proposed that the addition of 8 wt% SCFs, which lowered the friction and wear of the epoxy composites, promoted solid lubrication by free-rolling SCFs.