Influence of dilution rate on the microstructure and properties of FeCrCoNi high-entropy alloy coating

The kind of the alloying elements has obviously effect on the dilution rate, and the content of the Fe element has the direct ratio with the dilution rate. The change of the laser cladding parameters could not effectively improve the high dilution rate. The large dilution effect could transfer enough Fe elements to make sure the mixed entropy of the Fe0CoCrNi coating was similar to the theoretical mixed entropy of the FeCoCrNi high-entropy alloy. The redundant Fe element did not change the single FCC crystal structure of the coating. The atom radius among the Fe, Co, Cr, and Ni elements led to the large lattice dislocation of the FCC crystal lattice. The micro-hardness of the FexCoCrNi coatings had a direct ratio with the Fe element, because it could enhanced the level of the lattice dislocation. In addition, the redundant Fe element deteriorated the self-passivation ability of the FexCoCrNi coating in the 3.5 wt% NaCl solution. In the high-temperature oxidation test, the dilution effect of the substrate promoted the formation of the Fe oxides. Thereby, the excess Fe element could reduce the high-temperature oxidation resistance.206