Zr-N surface alloying layers fabricated in pure titanium substrates by plasma surface alloying

The Zr-N alloying layers were prepared on the surface of pure titanium substrates by plasma surface alloying technique to improve the surface properties. The microstructure, chemical composition, and hardness of Zr-N surface alloying layers were analyzed to understand the mechanisms of surface alloying and hardness improvement. The tribological performance of Zr-N surface alloying layers was studied by ball-on-disc wear machine. The results show that Zr-N alloying layers formed are homogeneous and compact. The Zr-N surface alloying layer consists of an outer nitride layer and an inner diffusion zone of zirconium and nitrogen. The surface treatment enhances the hardness of the surface layers of pure titanium substrates greatly and a surfaces hardness of HK1870 is obtained. Though Zr-N surface alloying layer does not show friction-reducing effect, it improves the wear resistance of pure titanium obviously.