Study on the tribological behaviors of the phenolic composite coating filled with modified nano-TiO2

In order to overcome the disadvantages generated by the loosened nanoparticle agglomerates dispersed in polymer composite coatings, nano-TiO2 particles are modified using trifluoracetic acid. The friction and wear properties of the phenolic coatings filled with different surface treated nano-TiO2, sliding against AISI-C-52100 steel ring under dry sliding, were investigated on a MHK-500 wear tester. Owing to the effective improvement of their dispersibility in the phenolic coating, compared with the cases of untreated nano-TiO2, the employment of modified nano-TiO2 provided the phenolic coating with much better tribological performance. Worn surfaces of the untreated nano-TiO2 or modified nano-TiO2 filled phenolic coating and transfer films formed on the surface of the counterpart ring sliding against the composite coating were respectively investigated by SEM and optical microscope (OM), from which it is assumed that the optimal content of TiO2 or TF-TiO2 is able to enhance the adhesion of the transfer films to the surface of counterpart ring. As a result, the wear resistance of the phenolic composite coating filled with modified nano-TiO2 was significantly enhanced, especially at extreme wear conditions, i.e. high contact pressures.