Effect of magnetron sputtering Nb coating on fretting corrosion resistance of biomedical Ti6Al4V alloy

By utilizing magnetron sputtering coating technology, a Nb coating was prepared on the surface of the Ti6Al4V substrate, and the basic properties of the Nb coating were thoroughly investigated. The Nb coating exhibited a dense structure, uniform elemental distribution, low surface roughness, good film quality, high adhesion strength between the coating and the substrate, and enhanced the microhardness of the Ti6Al4V alloy surface. Subsequently, fretting corrosion experiments were conducted to comprehensively analyze the influence of the Nb coating on the fretting corrosion characteristics of the Ti6Al4V substrate. The Nb coating significantly improved the fretting corrosion resistance of the Ti6Al4V alloy. Specifically, the introduction of the Nb coating reduced the tangential force, friction coefficient, total fretting energy, and frictional dissipation energy at the contact interface during the fretting process, thereby improving the fretting running characteristic of the Ti6Al4V alloy. Simultaneously, the Nb coating reduced the wear depth and wear volume of the Ti6Al4V alloy surface, altered the fretting damage features and mechanisms of the Ti6Al4V substrate surface, and enhanced the wear resistance of the material surface. Additionally, the Nb coating increased the open circuit potential and corrosion potential of the Ti6Al4V substrate, decreased the variation in open circuit potential (OCP) and corrosion current, thereby enhancing the corrosion resistance of the material surface.