Corrosion resistance and hydrophilic properties of plasma sprayed Ni+5% Al coatings

In this research, the AZ31 Mg alloy was coated with Ni5Al powder, using a plasma spray method. Effects of nuzzle distance and number of passes on corrosion behavior, hydrophilic properties and phase structure of the coated layer were studied. Samples in different distance of nozzle (150 and 300 mm) and different number of passes (2, 4 and 6) were examined. Corrosion behavior characterization was carried out using electrochemical impedance spectroscopy and potentiodynamic polarization methods. Hydrophilic properties of the coated layer were also investigated by the contact angle method. Results showed that by increasing the number of passes, the corrosion resistance and the contact angle were increased. On the other side, by increasing the nuzzle distance, the corrosion resistance and the contact angle were decreased. The Coated sample with 6 pass coating and nozzle distance of 150 mm had the best corrosion behavior and hydrophilic properties.