Fretting wear of TC11 and surface modified layers in seawater

Different surface modification experiments were performed on titanium alloy TC11 to obtain MAO coating, N⁺ ion implanted layer and DLC multilayer film. Phase composition and microstructure were examined using scanning electron microscopy (SEM), X-ray diffraction (XRD) and Raman spectroscopy. Fretting wear performances of TC11 and different surface modification layers in simulated seawater environment were studied on the SRV-IV fretting wear machine. And effects of modification on the friction coefficient, wear resistance and abrasion mechanism were investigated. Results show that with the application of all above surface modifications, the fretting wear resistances of TC11 are improved. It is indicated that modified layers could cause the decrease of friction coefficient and wear volume compared with TC11. The reductions of wear volume are obvious, and the defending effect of DLC multilayer film is most outstanding. In the meantime, the friction coefficient in seawater is significantly lower than that in pure water. The wear volume reduction of TC11 in seawater compared with in pure water suggests that there's a negative interaction for TC11 between corrosion and wear. However, wear volumes of modified layers are slightly higher than the values in pure water.