Effects of sonication on anticorrosive and mechanical properties of electrodeposited Ni–Zn–TiO2 nanocomposite coatings

Ni–Zn–TiO2 nanocomposite coating was fabricated using the electrodeposition process with the aid of ultrasonic vibration (0, 108, 135, 162 and 216 W cm− 2 ultrasonic power densities) on mild steel disks. The properties of the nanocomposite film were investigated using scanning electron microscopy (SEM), energy dispersive X-ray (EDX), EDX-mapping, Vickers microhardness test, Tafel polarization test and electrochemical impedance spectroscopy (EIS). The results revealed a significant improvement of anticorrosive properties and hardness of the nanocomposite coatings compared to Ni–Zn alloy coating. Ecorr became more positive and changed from − 0.921 V for Ni–Zn alloy coating to − 0.789 V for Ni–Zn–TiO2 nanocomposite coating. Icorr decreased from 1.25 × 10− 5 A cm− 2 for Ni–Zn alloy coating to 3.46 × 10− 6 A cm− 2 for Ni–Zn–TiO2 nanocomposite coating. On the other hand, hardness increased from 253 HV for Ni–Zn alloy coating to 876 HV for Ni–Zn–TiO2 nanocomposite coating. The improvements were related not just to the content of nano-TiO2 in the coatings but also to surface homogeneity and nanoparticles uniform dispersion in the matrix of the coating.