Microstructure and corrosion resistance of sputter deposited Fe-Cr-Mo coatings

Abstract

Iron-chromium films with various molybdenum contents were deposited by magnetron sputtering from two targets: Fe-25Cr alloy and molybdenum metal. Films deposited on glass substrates were used to study the intrinsic corrosion resistance of the deposited materials, and films deposited on brass were used to investigate the corrosion behaviour of a film-metal substrate system. The corrosion behaviour was characterised by electrochemical polarisation experiments in RCI or NaCI solutions, respectively. The structure of the films became X-ray amorphous when the molybdenum concentration reached approximately 30 wt-%. Films with such high molybdenum content generally had a perfectly flat surface topography and exhibited a much improved corrosion resistance.