A parametric study of the microstructural, mechanical and tribological properties of PACVD TiN coatings

In order to design coatings with optimal wear and corrosion performance, knowledge of the structures and properties of the coatings and their dependence on the process parameters is required. Coatings of TiN deposited onto tool steels using an industrial, pulsed DC plasma-assisted chemical vapour deposition chamber were investigated. The process parameters, i.e. voltage, pressure, and flows of H 2,, Ar, N 2 and TiCl 4,, were varied. The microstructural, mechanical and tribological properties of the coatings were investigated using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, nanoindentation, pin-on-disc measurements and Rutherford backscattering spectrometry. The residual stress level and hardness varied significantly with changes in the process parameters, whereas the tribological properties displayed only minor variations.