Co-deposition of micro- and nano-sized SnO2 particles in the Zn-matrix composite coatings produced from a Zn-sulphate bath by electroplating

Abstract The Zn-coating and Zn-composite coatings were produced by electroplating technique. The Zn-composite coatings are generated with the co-deposition of SnO2 microparticles and SnO2 nanoparticles. The deposit characteristics of coated samples have been depicted by SEM photo-micrographs and contact angle study. The corrosion behavior of the prepared coated samples was evaluated by electrochemical tests such as polarization (Tafel) and electrochemical impedance spectroscopy (EIS). The bare Zn-coating shows a more negative Ecorr value (-1.121 V vs SCE) whereas, Zn-nano SnO2 composite coating exhibited less negative Ecorr (-1.084 V vs SCE) compared to Ecorr (-1.091 V vs SCE) of Zn-micro SnO2 composite coating. Similarly, the Rct values of bare Zn-coating, Zn-micro SnO2 composite coating and Zn-nano SnO2 composite coating were found to be 92 Ω cm2, 907 Ω cm2, and 1919 Ω cm2, respectively. The studies revealed the increased corrosion resistance property of Zn-nano SnO2 composite coating than Zn-micro SnO2 composite coating.