Investigation on microstructural, anti-corrosion and mechanical properties of doped Zn-Al-SnO2 metal matrix composite coating on mild steel

In this study, the microstructural, mechanical and anti-corrosion properties of nanocomposite Zn-Al coating containing SnO2 nanoparticles prepared from sulphates electrolyte by electrodeposition on mild steel substrate was investigated. The morphologies of the coating were analysed using SEM/EDS, AFM Raman and X-ray diffraction. The anticorrosion behaviour of the coating prepared with different concentrations of SnO2 (7 and 13 g/L) and potential of (0.3 and 0.5 V) was examined in 3.65% NaCl solution by using linear polarization techniques. The wear and hardness properties of the coatings were performed under accelerated reciprocating dry sliding wear tests and diamond micro-hardness tester respectively. The results obtained showed that the incorporation of SnO2 in the plating bath brings an increase in corrosion resistance and mechanical properties of Zn-Al-SnO2 composite coatings. The SEM images showed a homogeneous grain structure and finer morphology of the coatings. The hardness values was found to improve with the amount of the SnO2 embedded into the Zn-Al metal deposit and effective deposition parameters.