Microstructure and sliding wear behavior of pure titanium surface modified by double-glow plasma surface alloying with Nb

In the present work, a Ti-Nb alloyed layer was successfully formed on the pure titanium surface by double-glow plasma surface alloying technology with Nb and the wear resistance has been investigated. The microstructure, phase identification and elements distribution were analyzed by optical microscope (OM), scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and X-ray powder diffraction (XRD). Specified tribological characterization was carried out by using a ball-on-disc tribometer and MicroXAM Surface Mapping Microscope at room temperature. The nano-hardness of the alloyed layer was also improved from 3.25 GPa to 5.25 GPa. As compared with pure titanium substrate, the friction coefficient of the alloyed layer was reduced from 0.57 to 0.27. The wear volume and relative wear rate at room temperature were reduced by 82% and 86%, which corresponded to an improvement of wear resistance. In the Haemolysis test, the treated sample exhibited better biocompatibility. Measuring the anodic polarization curves in Tyrode's solution, the treated sample indicated a decreased corrosion rate.