The feasibility of producing nickel aluminide coatings on steel substrates by controlled reactive thermal processing of plated precursors was studied. The basic procedure comprises plating of a steel substrate surface with nickel and aluminum, and controlled partial melting of the precursor to cause in-situ formation of nickel aluminides in the resultant coating. Infrared radiant heating was mainly used as the heat source, although plasma arc and Nd:YAG laser were also tested. The nickel aluminide that formed predominantly in the present study was the aluminum-rich compound Ni_2Al_3. Insufficient heat input conditions resulted in non-monolithic coating consisting of Ni_2Al_3 and aluminum while higher heat inputs produced monolithic Ni_2Al_3 coatings.
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