Study of the Tribological Properties of Diffusion Coated NiTi Intermetallic on Cp Titanium

In this work, dry tribological behaviors of commercial pure (Cp) titanium and diffusion coated titanium were studied and compared. Wear tests were performed by a pin on disk tribometer using 52100 steel pins, under various loads of 10, 20, and 40 N. Worn surfaces were examined by scanning electron microscope, equipped with EDS analyzer. The wear rates of the coated materials were lower than those of the Cp titanium. This is mainly attributed to the higher hardness of the NiTi layer (about 280 HV) which is 1.5 times higher than that of the untreated titanium (about 180 HV). In addition, the SEM analysis of the worn surfaces revealed that the formation of tribological layer on the surface of the diffusion treated material effectively lowered the wear rate. The results also demonstrated a lower coefficient of friction in the treated specimens compared to those of the Cp materials.