Ni modified layer is prepared on the surface of pure titanium by plasma surface alloying technique. Surface appearance, micro-structure morphology, composition distribution, phase structure and microhardness of Ni modified layer are analyzed. Tribological performance and fatigue behaviors of Ni modified layer of pure titanium are observed using Pin-on-disc tribometer and repeated impact test. The results indicate that the surface mean Ni concentration of Ni modified layer is nearly 18% which is composed of TiNi, Ti2Ni and Ti phase. The maximum surface microhardness of Ni modified layer is approximately 580 HV which is almost two-fold of the hardness of the substrate. The wear resistance of Ni modified layer is improved obviously. The wear mechanism of Ni modified layer shows slight abrasion wearing, while pure titanium is abrasion and adhesion wearing. Ni modified layer presents better impact fatigue strength.
