Electrochemical Evaluation of Polyvinyl Butyral Coating Containing Polypyrrole/ZnO Nanocomposite for Preventing Corrosion 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 times of immersion 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.