Correlation between optical characterization of the plasma in reactive magnetron sputtering deposition of Zr-N on SS 316L and surface and mechanical properties of the deposited films

Optical and surface spectroscopies as well as nanoindentation techniques have been used to study ZrN coatings on 316L stainless steel obtained by DC-reactive magnetron sputtering. The deposit process was carried out using initial and working pressures of 10⁻⁶ Torr and 10⁻³ Torr, respectively. The experimental set-up for optical spectra acquisition was designed for the study in situ of the plasma in the deposition chamber. Auger spectroscopy, SEM and X-ray diffraction were used to characterize the coatings. Nanoindentation tests were carried out to measure the mechanical properties of the coating. Plasma characterization revealed the presence of CN molecules and Cr ions in the plasma. Surface spectroscopy results showed that ZrN, Zr₃N₄ and ZrC coexist in the coating. These results allowed the understanding of the mechanical behavior of the coatings, demonstrating the importance of the plasma characterization as a tool for tailoring the properties of hard coatings.