Influence of the aspect ratio of sodium iron titanate whiskers on the mechanical and tribological performances of fluorocarbon composite coatings

Inorganic–organic composite coatings with fluoroethylene vinyl ether (FEVE) resin as polymer matrix and sodium iron titanate (NFTO) whiskers with different aspect ratios as reinforcement filler are prepared by the liquid-phase blending method. The influence of aspect ratio and content of NFTO whiskers on the morphology, and the mechanical and tribological performances, of NFTO-reinforced FEVE composite coatings are investigated. The addition of NFTO whiskers can obviously enhance the mechanical and wear resistance performances of the composite coatings and reduce the friction coefficient. The worn surface and wear debris of the composite coatings are studied with scanning electron microscopy (SEM) to reveal the friction-reducing and wear resistance mechanisms. The composite coating filled with ~10 wt.% NFTO whiskers has the best wear resistance performance, since the monodispersed hard whisker can carry the load applied on the sliding surface and reduce the adhesive wear of the polymer matrix. Among the three types of NFTO whiskers, the whiskers with a medium aspect ratio show the best reinforcement effect since they provide the optimum mechanical support to the polymer matrix and cannot be pulled out from the matrix easily.