Effect of thermal treatment on the interfacial reaction, microstructural and mechanical properties of Zn-Al-SnO2/TiO2 functional coating alloys

In this paper, the microstructure and thermal treatment behavior of Zn-Al-SnO2/TiO2(Zn-Al-Sn/Ti) produced through co-deposition route was investigated. 7.0-13.0 wt% TiO2 and SnO2 was added to Zn-Al bath. Thermal treatment was done for 2 h at 200 °C, 400 °C and 600 °C. The ageing characteristics of the coated alloys were evaluated using (SEM/EDS) and XRD. The hardness and wear value of the thin film were examined with micro-hardness and UMT-2 sliding tester respectively. The corrosion properties were evaluated by linear polarization in 3.65% NaCl. From the result obtained, the coating exhibited good stability. The uniform distribution of the composites on the fabricated alloy and age-treatment were the major factor responsible for the mechanical and electrochemical improvement. The optimum value was obtained at Zn-Al-7Sn-Ti-0.3V-S for as-coated and Zn-Al-7Sn-Ti-0.3V-S at 400 °C for the thermal-aged samples. The stabilities in hardness and corrosion resistance against the working substrate were attributed to the formation of coherent and uniform precipitation in the metal lattice.