Study On The Structure And Corrosive-Wear Behavior Of Mo-N Diffusion Layers On T16a14V Alloy With Double Glow Plasma Surface Alloying Technique

Titanium and its alloys, such as Ti-6Al-4V, are widely applied to aerospace, chemical and bioengineering due to their high ratio of strength to weight, high temperature resistance, corrosion resistance and biocompatibility. However, their poor wear resistance and a tendency to galling are the major concerns to potential users.Numerous surface engineering technologies have been explored to enhance the wear resistance of the titanium alloys while maintaining their corrosion resistance and biocompatibility. Coating, plasma immersion ion implantation (PHI), and plasma nitriding are amongst the technologies explored. Whereas the wear resistance of Ti-6Al-4V alloy at low stresses and low velocities can be improved by the above techniques, cracking and debonding often occur at the modified layers at high sheer stresses. One of the solutions to the problems is increase the thickness of modified layers to withstand the high shear stresses during sliding wear. However, thick modified layers are difficultly obtained using coating, PHI, and plasma nitriding technologies. On the other hand, increasing thickness of the modified layers may result in an increase in residual stress and the risk of debonding. Therefore, a Mo-N modified layer was explored for the surface modification of Ti-6Al-4V alloy using an innovative plasma surface alloying technology. The objective of the study is to characterize the tribological properties of the thick, adhesive, and wear resistant surface modified layer obtained using this technology.In the paper, the double glow plasma surface alloying technique is carried out on titanium alloy Ti6A14V. The surface alloy layers were obtained with the three different ratio of N to Ar. The structure, electrochemical, wear and corrosive-wear behaviors of the surface alloy layers were investigated respectively.Results of the diffusion layer structure were investigated. It indicate that the surface alloy layer's structure is affected by the ratio of N to Ar to a certain degree. In view of thermodynamics and kinetics, the electrochemical properties of the surface alloy layers were investigated and compared with that of TJ6A14V base material. Results indicate that self-corroding electric potentials is higher than that of Ti6A14V base material, and corrosion-rate to be similar or equivalent in experimental conditions. The wear and corrosive-wear behaviors'of the surface alloy layers were studied. The results show that these Mo-N diffusion layers not only significantly lowers the coefficient of friction, but also enhances the wear resistance of the titanium alloy in different solutions.