Surface modification of titanium for wear resistance through solid-phase diffusion of iron.

Low-wear resistance is a considerable problem with titanium. Despite the excellent wear resistance of Ti-Fe alloys, they exhibit brittleness, complicating their bulk usage. We developed a surface modification method for Ti involving the solid-phase diffusion of iron onto its surface. We coated iron onto the titanium surface and applied heat to successfully form a Ti-Fe alloy layer only on the outermost surface of titanium. The alloy layer exhibited a gradient structure characterized by a continuous decrease in iron concentration from the surface inward, without forming a distinct interface with the base material. Under various heat treatment conditions, the outermost alloy phase of the diffusion layer, in the β phase, resulted in surfaces with exceptional wear resistance. The improved wear resistance can be attributed to the potential surface structure of the Ti-Fe alloy, which combines hardness and ductility. This titanium-integrated structure, resulting from the gradient composition, reduces the likelihood of delamination.