Microstructure and properties of Ni60 alloy coating prepared by electromagnetic compound field assisted laser cladding

In this study, Ni60 high-hardness alloy coatings were prepared on pure iron substrates by electromagnetic compound field (ECF) assisted laser cladding. By the application of synchronous alternating electric field and steady magnetic field, the effects of different electromagnetic parameters on the surface topography, phase composition and microstructure of the coatings were studied. The microhardness, electrochemical corrosion, wear property, and residual stress distributions of the coatings were also investigated. The results showed that ECF did not change the phase composition of the coatings, but had a significant influence on the microstructure. The alternating electromagnetic force generated by ECF had a mechanical stirring effect on the molten pool, which can increase the nucleation rate and play the role of refining grains. With the increase of the electromagnetic parameters, the grain refinement effect was enhanced, thus leading to a finer microstructure. Moreover, ECF can also help to reduce the cracking tendency and residual stress of the coatings. Compared with the coating prepared without ECF, the coatings with the applied ECF exhibited higher microhardness, corrosion and wear resistance, and fewer number of cracks. The coating with the best comprehensive properties can be obtained under the electromagnetic parameter of 0.2 T + 1200 A.