Inhibiting tribocorrosion damage of Cr/CrxN coatings by multi-layer design

Abstract The two-layer and multi-layer Cr/CrxN coatings were fabricated on 316 L stainless steel (316 L SS) substrates by the arc ion plating technique. The two-layer Cr/CrxN coating was a typical CrN coating with an adhesive Cr layer. And the multi-layer Cr/CrxN coating design was in two dimensions. In the first dimension, the multi-layer Cr/CrxN coating consisted of alternative Cr/CrN layers with the thickness ratio of 1:5; in the second dimension, the alternative Cr2N layers with the thickness of 10 nm were inserted in CrN layers. This design was expected to increase transverse interfaces in a smaller scale. The microstructures, mechanical, corrosion and tribocorrosion performances of both Cr/CrxN coatings were systematically investigated. The results showed that the special multi-layer design of Cr/CrxN coatings improved mechanical, anti-corrosion and anti-tribocorrosion performances. Compared with the two-layer Cr/CrxN coating, the reduced tribocorrosion damage of the muti-layer Cr/CrxN coating was closely related to the inhibited synergistic effect between electrochemical corrosion and mechanical wear. In conclusion, the multi-layer Cr/CrxN coating was more suitable to work as the surface protective coating than the two-layer Cr/CrxN coating in seawater.