Improvement of Corrosion Behavior of Al۷۰۷۵ by Applied Ti/TiN Multilayer Coating with High Vacuum Magnetron Sputtering

۷۰۷۵ aluminum alloys are widely used in industry, due to their properties such as specific strength and good fatigue resistance. The nitride multilayer coating, which applied by physical vapor deposition (PVD) process have shown good improvement in abrasive  resistance, but their columnar structure led to decreasing corrosion resistance behaviors. In this paper, multilayer coatings of Ti/TiN with ۶ layers applied on Al ۷۰۷۵ as a substrate by high vacuum magnetron sputtering. Then GIXRD, FESEM and AFM were used to assessed phase behavior, structure and morphology of the coating, respectively. As well as the corrosion behavior of coating was investigated by using electrochemical impedance in simulated body fluid such as Ringer’s solution at ۳۷ ºC. The results show production of homogeneity and uniformity multilayer coating, with cutting the column structure of titanium nitride, which  increasing the charge transfer resistance by ۵۶ times compared with Al ۷۰۷۵ and also no pitting was seen at the coated samples after ۷۲ hours of immersion, with enhancing of corrosion resistance by ۲۸۴ % compare to ۴۸ h of immersion.