Improving wear and corrosion resistance of AISI 304 stainless steel by a multilayered nanocomposite Ti/TiN/TiSiN coating

In this paper, to simultaneously enhance the wear and corrosion resistance of AISI 304 stainless steel, a multilayer nanocomposite Ti/TiN/TiSiN coating is deposited on this alloy utilizing cathodic arc evaporation method. The results show that the deposited coating has a multi-layered structure including layers of Ti, TiN and TiSiN with the thicknesses of 0.71, 1.84 and 0.68 mu m, respectively. The coating has a nanocomposite-type microstructure consisting of TiN nanocrystallines with size of 5.6 nm embedded in an amorphous matrix of SiNx. The graded architecture of Ti/TiN/TiSiN coating, as well as the plasma nitridation of the substrate, contribute to improving the adhesion strength of the deposited layer. The deposition of Ti/TiN/TiSiN layer on AISI 304 stainless steel decreases its coefficient of friction from about 0.5 to 0.1 and remarkably increases wear resistance against Al2O3 ball about 18.7 times which is directly related to the high hardness of the coating (similar to 3700 HV0.01). The electrochemical investigations in an aerated 3.5 wt.% NaCl aqueous solution reveal that the deposition of Ti/TiN/TiSiN coating on AISI 304 stainless steel increases its corrosion resistance by blocking the penetration of corrosive species and preventing the exposure of the substrate to these destructive agents.