Abstract
Electromagnetic field-assisted laser cladding technology was employed successfully to prepare in-situ gradient Ti(C,N) in AlCoCrFeNi high entropy alloy coatings. The microstructure, elemental and phase distributions were investigated by SEM and XRD. The microhardness, wear resistance, and electrochemical corrosion behavior were studied. The results revealed that a gradient distribution of micro hardness from the substrate to coating was achieved when introducing the electromagnetic field, due to the gradient distribution of the Ti(C,N) ceramic phase. The gradient coating greatly improves the corrosion resistance of the material in 3.5% NaCl solution because more ceramic phases are formed on the surface to hinder the electron transfer during corrosion. A corrosion model has been created to better understand the corrosion mechanism of different composite coatings.

Key words
gradient coating, electromagnetic field, laser cladding; high entropy alloy

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