TiN-coating formation by pulsed Nd: YAG laser irradiation of titanium in nitrogen

Titanium was treated by pulsed Nd:YAG laser irradiation in nitrogen atmosphere, which led to nitrogen in-diffusion and TiN coating formation. The thickness of the TiN films was about 1.2 æm and the coatings had a universal hardness of about 11 GPa. The layers were investigated by X-ray diffraction at grazing incidence and resonant nuclear reaction analysis for nitrogen depth profiling. Fitting of the experimental depth profiles gave information about the physical processes (diffusion time and depth) with respect to the achieved hardness. The microscopic properties like lattice constants and the variation of the nitrogen content were evaluated. A relationship between laser scan parameters and coating properties could be revealed. Thus, it was possible to determine the physical limits such as film thickness, nitrogen content, and hardness of this direct laser synthesis. Keywords: Titanium, Hardness, Melting depth, Laser synthesis, Titanium nitride, Coatings