Hot-dip galvanization with pulse-electrodeposited nickel pre-coatings

The galvanizing process whereby steel is electrodeposited with nickel using pulsed current waveforms and hot-dipped in a molten zinc bath at 450 degrees C is investigated here as a potential route to mitigate the coating overgrowth problem The influences of processing parameters including electroplating and galvanizing durations on the evolutions of microstructure and phase structures and polarization characteristics of galvanized steels are explored The results from the polarization study and salt spray tests indicate that the galvanized coating prepared with a nickel pre-coating comprising zinc-nickel intermetallic layers exhibits significantly better corrosion resistance than the conventionally-galvanized steel (C) 2010 Elsevier Ltd All rights reserved