Selectable surface nitridation of titanium using focused pulsed Nd:YAG laser irradiation with nitrogen gas blow

摘要

In the present study, we demonstrated that a surface nitride layer with high surface hardness and good cell attachment performance could be produced on an arbitrary area of a titanium (Ti) substrate by using focused pulsed Nd:YAG laser irradiation accompanied by nitrogen gas blow. A focused laser beam induced nitrogen plasma in the vicinity of the Ti substrate surface. This plasma made it possible to forma nitride layer with a sufficient thickness, even when the laser powerwas low. The produced surface layerwas approximately 1100 nmin thickness and was composed of TiN and Ti; the concentration of TiN eventually decreased with increasing depth. The hardness of the laser-treated surface was approximately 7.5 GPa,which was approximately five times that of the untreated Ti surface. Furthermore, the surfacewettability of the Ti substratewas drastically improved by treating it with focused laser, which enhanced the cell attachment performance of the substrate.We concluded that the surface nitriding process using focused pulsed Nd:YAG laser is an excellent surface modification technique for Ti materials that can simultaneously improve their wear resistance and cell attachment performance.