Characterization and corrosion behaviors of TiN/TiAlN multilayer coatings by ion source enhanced hybrid arc ion plating

TiN/TiAlN multilayer coatings with various bilayer numbers were deposited on AISI 410 martensitic stainless steel using ion source enhanced hybrid arc ion plating system. The influences of different bilayer numbers on structure, mechanical properties and corrosion behaviors of TiN/TiAlN multilayer coatings were investigated comparatively. The as-deposited coatings were predominantly composed of fcc-TiN and solid solution (Ti, Al) N phases with (111) preferred orientation, and the growing tendency towards preferential orientation decreased as the increase of bilayer numbers. With increasing bilayer numbers, microhardness of the coatings was enhanced gradually for the increased interfaces and refined crystals, reaching a maximum of 3800 HK0.025 at the coating with 12 bilayers. Multilayer coatings exhibited an abrasive wear mechanism against WC pair, and possessed an excellent tribological performance in comparison to MSS substrate. According to electrochemical results, the coating with bilayer number of 12 presented a high free corrosion potential combined with the lowest corrosion current density, highest polarization resistance, highest protective efficiency and largest charge transfer resistance than that of other bilayer numbers owing to the increased layered interfaces and high structural density.