Effect of substrate temperature and nitrogen concentration during sputtering on corrosion behaviour of AlN coatings

Abstract

Aluminium nitride coatings were formed on stainless steel substrate by DC-reactive balanced magnetron sputtering at various nitrogen concentrations in the sputtering gas mixture, and different substrate temperatures. The electrochemical corrosion behaviour of the coatings obtained was studied in 0.5 M H₂SO₄. Continuous improvement in corrosion resistance of the coatings was observed with increasing coating deposition temperature up to 500 °C. The corrosion potential shifted from −0.66 V_SCE at 100 °C to −0.33 V_SCE at 500 °C. Accordingly, the corrosion current density decreased significantly with increase in the deposition temperature. However, no major difference in corrosion behaviour could be noticed for the coatings formed at various nitrogen concentrations.

Keywords:

• Aluminium nitride
• Coating
• Sputtering
• Corrosion