Characteristics of dilution and microstructure in laser cladding Ni-Cr-B-Si coating assisted by electromagnetic compound field

•Electromagnetic field could reduce the dilution rate of laser cladding coating.•Electromagnetic field made the amount of Cr borides increase.•Electromagnetic field made Cr content increase while Fe content decrease in Cr borides.•Electromagnetic field reduced the range of columnar dendrite crystals at the bottom of the coating. Ni-Cr-B-Si coatings were prepared on the surface of pure iron using an electromagnetic field assisted laser cladding technique. The effect of electromagnetic field on the cross-sectional morphology, the microstructure and the element distribution was investigated. The results showed that the dilution rate of coatings reduced and the grain size of Cr borides was refined under the electromagnetic field. The volume fraction of Cr borides in the coatings increased and the distribution morphology of phases is related to grain boundary wettability. The length of columnar dendrite crystals at the bottom of the coatings decreased with the increase of the electromagnetic force.