The effect of Si incorporation on the mechanical properties and corrosion behaviour of a-C:H and a-C:H:Si coatings

This paper aims to present the corrosion behaviour and mechanical properties of hydrogenated amorphous carbon films (a-C:H) and Si incorporated hydrogenated amorphous carbon (a-C:H:Si) coatings. The a-C:H and a-C:H:Si top coatings were deposited on 100Cr6 steel substrates (using also interlayers) by plasma assisted chemical vapour deposition technique. In terms of mechanical properties, nanoindentation hardness, elastic modulus and adherence were measured. The corrosion behaviour was evaluated using both salt spray test method and electrochemical corrosion test (potentiostatic method). According to the experimental results, the addition of Si into a-C:H films improves the corrosion resistance of these ones in comparison with the variants without Si. However, the addition of Si produces a light decrease of the mechanical properties.