A Novel Treatment to Selectively Harden Ti6Al4V Surfaces

Various surface treatmentshave been developed on titanium andits alloy to improve their tribological properties. However, for somecomponents, only specific surfaces need to be hardened rather thanthe whole surfaces. This study develops a duplex heat treatment includingselective surface hardening by prepainting TiO2 powdersand thermal oxidation. It is found that the TiO2 powderlayer can be used as an oxygen reservoir for boosting diffusion treatmentat temperatures of 800-900 & DEG;C. The abundance of oxygenprovides high potential and accelerates the diffusion process, deeplyhardening the surface case. Moreover, the duplex treatment is optimalfor selectively hardened surfaces with high load-bearing capacityand much improved tribological properties. Prepainting the surfacesthat need to be hardened is easy to operate and has good potentialto be applied in industry.