Bilayer period effect on corrosion–erosion resistance for [TiN/AlTiN]n multilayered growth on AISI 1045 steel

The aim of this work is to study the electrochemical behavior, under a corrosion–erosion condition, of [TiN/AlTiN]n multilayer coatings with bilayers periods of 1, 6, 12 and 24, deposited by a magnetron sputtering technique on Si (1 0 0) and AISI 1045 steel substrates.The TiN and AlTiN structure for multilayer coatings were evaluated via X-ray diffraction (XRD) analysis. Silica particles were used as an abrasive in the corrosion–erosion test within a 0.5 M H2SO4 solution at an impact angle of 30° over the surface. The electrochemical characterization was carried out using a polarization resistance technique (Tafel), in order to observe changes in the corrosion rate as a function of the bilayers number (n) or bilayer period (Λ). Corrosion rate values of 359 mpy in uncoated steel substrate and 1.016×10−6 mpy for substrate coated with [TiN/AlTiN]24 under impact angle of 30° were found. This behavior was related with the mass loss curve for all coatings and the surface damage was analyzed using SEM images. These results indicate that TiN/AlTiN multilayer coatings deposited on AISI 1045 steel provide a practical solution for applications in erosive–corrosive environments.