Investigation on corrosion performance of multilayer Ni-P/TiO2 composite coating on steel

Abstract

Electroless nickel coating treatment improves the corrosion resistance of mild steel. This work aims at studying the corrosion behavior of electroless Ni-P/TiO2 composite and multilayer coatings applied to the mild steel substrate as their as-plated state and furnace annealed at various temperatures and compared both the coatings' corrosion performance. The corrosion behavior of the deposits was evaluated by potentiodynamic polarization studies in 3.5 wt% sodium chloride solution. The results showed that the corrosion resistance of the multilayer coating was two times higher compared to the composite coatings. Further, the corrosion mechanism was discussed in terms of microstructure, phase transformation, grain size, and microstrain.