Electrodeposited Ni‐Cr and Ni‐Cr‐P Alloys

Macrocrystalline Ni‐Cr and amorphous Ni‐Cr‐P were electrodeposited on steel substrates. It is easier to obtain the Ni‐Cr‐P deposit from the aqueous solution incorporating dimethylformamide and methanol in the presence of sodium hypophosphite than from a pure aqueous chloride solution. The chromium contents of the platings decrease as the bath temperature increases. The fcc nickel and r phase of as‐deposited low Cr% plating converts to fcc structure upon heat‐treatment, while the high Cr% plating is a bcc chromium structure. The amorphous high Cr% Ni‐Cr‐P plating converts to bcc chromium and Ni‐Cr phosphide phases upon heat‐treatment, which also gives rise to a maximum hardness of ∼Hv 1050 at around 500°C.