Electrochemical Evaluation of Polyvinyl Butyral Coating Containing Polypyrrole/ZnO Nanocomposite for Corrosion protection of Al Alloy

In this work, polypyrrole/ZnO nanocomposite (PPy/ZnO NC) was produced through synthesis of polypyrrole polymer in the presence of ZnO nanoparticles. The corrosion behavior of polyvinyl butyral coatings without and with different weight percentages of nanocomposite on the surface of 7075 Al alloy was investigated in 3.5% NaCl solution at different immersion times using electrochemical impedance spectroscopy (EIS) and electrochemical noise (EN) techniques. The coating with 0.025% PPy/ZnO NC revealed the highest corrosion resistance. In order to analysis of EN data, wavelet transform was used to obtain the standard deviation of partial signal (SDPS) plots. The good agreement between the EIS and EN results indicates that the EN technique, as well as the EIS method, can be used successfully for the corrosion evaluation of coatings.