EIS study of Ti/TiN nanostructured coating applied on Al 7075 by high-vacuum magnetron sputtering

In this study, corrosion behavior of nanostructured multilayer coatings of Ti/TiN applied on the 7075 aluminum substrate was evaluated by EIS method. Ti/TiN nano scale multilayer coatings were deposited on surface of samples by high-vacuum magnetron sputtering process, then structure and morphology of the coating were analyzed by using GIXRD, FESEM and AFM, afterwards, the corrosion behavior of coating was investigated by Nyquist and Bode phase curves after1, 12, 24, 48, 60 and 72 hours of immersion in 3.5% NaCl solution. Results show, the applying of nanostructured multilayer coating and interrupting columnar structure of TiN by the Ti as an intermediate layer causes to increase the impedance and corrosion resistance of Al7075 about 43 times compare with bare of Al7075, which proving that this coating is so effective for enhancing of corrosion behavior of Al7075