Electrochemical and Hydrogen Embrittlement of a Micro-Alloy Steel Coated with Nanocrystalline Nickel by Pulse Electrodeposition

A fine-grain micro-alloy (MA) steel coated with nanocrystalline (NC) nickel by pulse electrodeposition (PED) has been studied by electrochemical impedance spectroscopy (EIS) in a 3.5 wt. % NaCl solution and shown to have improved corrosion resistance. Hydrogen embrittlement (HE), assessed by a slow strain rate test (SSRT) at a strain rate of 2 x 10(-6 )s(-1), showed that the uncoated MA steel is highly susceptible to HE, whereas the NC Ni coated steel is resistance to HE. Fractographs have revealed characteristic brittle and ductile fracture features for the MA and NC Ni coated steels, respectively.