Corrosion behavior of electroless Ni-P/TiO2nanocomposite coatings

Composite Ni–P/nano-TiO2 coatings were prepared by simultaneous electroless deposition of Ni–P and nano-TiO2 on a low carbon steel substrate. The deposition was carried out from stirred solutions containing suspended nano-TiO2 particles. The Ni–P and Ni–P/nano-TiO2 coatings before and after heat treatment were characterized by X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy. The micro-structural morphologies of the coatings significantly varied with the nano-TiO2 content. The corrosion resistance of as-plated and heat-treated Ni–P and Ni–P/nano-TiO2 coatings was investigated by anodic polarization, Tafel plots and electrochemical impedance spectroscopic (EIS) studies in 3.5% NaCl solution. Ni–P/nano-TiO2 coating exhibited superior corrosion resistance over Ni–P coating. Copyright © 2015 John Wiley & Sons, Ltd.