Microwave cladding of Inconel-625 on mild steel substrate for corrosion protection

In the present work, Inconel-625 cladding was performed on a mild steel (MS) substrate through a cost-effective microwave technique. Cladding was performed in an industrial microwave oven operated at 1.2 kW and 2.45 GHz. The XRD observation indicates the presence of Laves and carbide phases in addition to a Ni-Cr-Fe based face-centered-cubic (fcc) matrix in the fusion zone microstructure of the clad specimen. The microstructural characterization shows a homogenous and dense microstructure with a porosity value of less than 1%. The columnar dendrites grew perpendicularly to the substrate was observed in the clad zone microstructure. The average microhardness of the deposited clad was significantly higher than that of the base metal (MS), indicating improved surface properties of the base material. Further, corrosion testing indicates that the clad specimen has significantly higher corrosion resistance than that of the base metal (MS) in a 3.5 wt% NaCl solution. (paper)