Silicon influence on corrosion resistance of magnetron sputtered ZrN and ZrSiN thin films

This study compares the corrosion resistance of ZrN and ZrSiN films deposited on AISI 430 steel by the magnetron sputtering technique. Corrosion resistance was evaluated using electrochemical impedance spectroscopy (EIS) technique, in 3.5% (wt./v) NaCl solution. The chemical and morphological film characterisation was carried out by Rutherford backscattering spectrometry (RBS), grazing incidence X-ray diffraction and scanning electron microscopy (SEM). The RBS analysis showed that 51.5Zr–48.5N and 43.5Zr–7.6Si-48.9N (at.-%) coatings were deposited by using magnetron sputtering technique on AISI 430 ferritic stainless steel. According to the results of EIS and SEM, the ZrSiN thin film was more homogeneous and effective in protecting AISI 430 steel against corrosion than the ZrN thin film, in the studied solution. The corrosion mechanism showed a difference: the ZrN-coated steel showed a localised corrosion through pores in the coating and the ZrSiN showed uniform corrosion at the coating-steel interface.