RIBAD Deposition of TiN on Magnesium Alloy

TiN coatings were produced by depositing a series of Ti layers and subsequently ion implanting 80 keV nitrogen ions. TRIDYN FZR software simulation was used to estimate the maximum Ti layer thickness which could be successfully transformed to TiN by ion implantation. The chemical profile of these coatings was achieved by conducting a series of EDS measurements across coatings, sectioned at shallow angles. It was found that the structure of the RIBAD TiN films produced changes significantly with the implanted nitrogen ion dose. Their hardness and wear resistance were found to increase rapidly as the post implantation time was increased up to 230 minutes, reaching a maximum of 27GPa and 2.5x10-12 mm3m-1N-1 respectively. On the other hand, the electrochemical corrosion resistance of TiN coated magnesium substrate was inferior to that of the untreated substrate material. The results suggest that the coating developed is attractive as a topcoat of a duplex coating; having as underlay a corrosion protective film. In a separate study, it has been shown that such coatings could be ion beam sputtered titania or alumina.