Microstructure and Properties of Cu-Fe Immiscible Coatings Fabricated via Combined Mechanical Alloying and Laser Cladding

This work reports on systematic investigation of the microstructure and comprehensive performances of Cu–Fe immiscible composite coatings prepared through the combination of mechanical alloying and laser cladding. The samples were characterized by scanning electron microscopy with an energy dispersive analysis, X-ray diffraction, a digital microhardness tester, current tester, electrochemical analyzer and magnetometer. Results show that the immiscible composite coatings are mainly composed of α-Fe particles dispersion in the ε-Cu matrix due to liquid phase separation, and this is exacerbated in addition of more Fe contents. Concentrated distribution of Fe–rich particles at either the top or bottom of the immiscible composite coatings are driven by the dominant mechanism of Marangoni and Stokes motion. With the increased fraction of Fe content, the microhardness and electrical resistivity increased, but a degradation in corrosion resistance. With the increased ball milling time, the electrical resistivity increased and the corrosion resistance is improved. Compared to the medium-carbon steel substrate, the immiscible composite coatings can achieve an improved corrosion resistance, as well as a maximum saturated magnetization of 10.172 emu/g and lowest coercivity of 17.249 Oe.