Accelerated Formation of Tribo-oxide Layer and Its Effect on Sliding Wear of a Titanium Alloy

Sliding wear tests of Ti-6Al-4Valloy against AISI 52100 steel were performed at room temperature. For the sake of improving the worse wear performance of the titanium alloy, an attempt of inducing the accelerated formation of protective tribo-oxide layers was made by artificially supplying nanoscale oxides of TiO2, Fe2O3 or their mixtures onto sliding tracks. Fe2O3 nanoparticles were noticed to have an advantage over TiO2 in the formation of sustainable tribooxide layers under higher load, which was ascribed to their rapid sintering rate and excellent load-carrying capability. The existence of Fe2O3 and Fe2O3-rich tribo-layers markedly reduced the wear rate of Ti-6Al-4V alloy under 10-50 N, whereas TiO2 and TiO2-rich nanoparticles as abrasives promoted wear in most cases. Clearly, TiO2 and Fe2O3 nanooxides as main ingredients of tribo-layers presented the opposite function in the sliding wear of Ti-6Al-4V alloy. In the titanium alloy/steel sliding system, the wear-reducing function of tribo-layers was suggested to be attributed to the appearance of Fe2O3, not TiO2.