Microstructure, hardness and corrosion behaviour of Ti/TiN multilayer coatings produced by plasma activated EB-PVD

Compressor blades used in gas turbine engines for marine applications must work in harsh environment such as erosion and corrosion. Multilayer nitride coatings produced by physical vapour deposition (PVD) have exhibited promising potential in improving the corrosion resistance. In this paper, three types of Ti/TiN multilayer coatings with different thickness ratios (M1: 10 nm/40 nm, M2: 20 nm/80 nm, M3: 30 nm/80 nm) were deposited onto 1Cr11Ni2W2MoV stainless steel substrates by plasma activated electron beam physical vapour deposition (EB-PVD). The microstructure, hardness and corrosion behaviour of the Ti/TiN multilayer coatings and TiN single layer coating were comparatively studied. The columnar grain growth of the TiN single layer coating was suppressed by the introduction of the Ti metallic sublayers. With the increase of the Ti sublayer thickness, the characteristics of the layered microstructure became more apparent. The substrates coated with Ti/TiN multilayer coatings exhibited better corrosion resistance (maximum 87% protection efficiency for M3) and higher hardness value (maximum 34.1 GPa for M1) than those coated with TiN single layer.