Development of smart oxidation and corrosion resistance of multi-doped complex hybrid coatings on mild steel

• The structure and thermal treatment properties of chloride Zn–Al–SnO2–TiO2 (Zn–Al–Sn/Ti).
• Thermal evaluation for 2 h at 200 °C, 400 °C and 600 °C.
• The coatings were evaluated using AFM, SEM/EDS and XRD, the hardness and wear.
• The best alloy value was obtained at Zn–Al–7Sn–Ti–0.3V–Cl system.
• Zn–Al–7Sn–Ti–0.3V–Cl at 600 °C for the thermal-corrosion samples.

The microstructure, mechanical and thermal treatment behavior of Zn–Al–SnO2/TiO2 (Zn–Al–Sn/Ti) produced through chloride deposition system was studied. 7.0–13.0 wt% TiO2 and SnO2 was added to chloride Zn–Al bath. A thermal treatment characteristic was done for 2 h at 200 °C, 400 °C and 600 °C. The ageing behaviors of the co-deposited alloys were evaluated using (SEM/EDS) and XRD. The hardness and wear value of the solid coatings were examined with micro-hardness and UMT-2 sliding tester respectively. The corrosion properties were investigated by linear polarization method in 3.65% NaCl environment. From the obtained results, the deposited alloys revealed excellent stability. The even distribution of the particulate on the produced coating and thermal-treatment were observed to cause the improvement on mechanical, tribological and electrochemical properties. The overall best coating was obtained at Zn–Al–7Sn–Ti–0.3V–Cl for as-coated and Zn–Al–7Sn–Ti–0.3V–Cl at 400 °C for the thermo-mechanical treated samples. The hardness, corrosion and micro-mechanical resistance performance against the working substrate were depended on the development of coherent and regular precipitation from the incorporated strengthening particulate.