Formation of β-NiAl nanocomposite coating by electrodeposition and effect of cerium ion doping on its oxidation mechanism

NiAl films were synthesized by electrodeposition of aluminum nanoparticles into the Ni matrix from a Watts bath and then were heat treated. The effects of current density and aluminum particles concentration on the particles distribution and the coating chemical composition were studied. It was observed that the Al concentration in the obtained NiAl coating is maximum (48.5 at%) at the current density of 4 Adm−2 for the coating solution with Al particles concentration of 50 gl−1. It was found oxidation resistance of the coating to improve in the presence of cerium ion up to 1 mM and then to decrease. Results of XPS analysis showed that cerium ion addition to the coating caused the formation of cerium oxide in both Ce3+ and Ce4+ states. During oxidation at 1000 °C, Ce3+ is converted to Ce4+. Consequently, oxygen vacancy decreases possibly leading to the increase of the oxidation resistance.