Investigation on the two-stage hierarchical phase separation in the laser cladded Cu–Mn–Fe coating

Abstract A self-assembled Cu–Fe–Mn composite coating with a two-stage phase separation feature was prepared by laser cladding Cu and Mn mixed powders on a 316 L stainless steel plate. The hierarchical phase separation feature and structural evolution of the coating were systematically investigated. The microstructure of the coating exhibits by dendrites of (Fe, Mn)-rich phase and nanosized (Cu, Mn)-rich phase embedded within the matrix of the (Cu, Mn)-rich phase. During the cladding process, the micrometer-sized (Fe, Mn)-rich dendrites formed due to the primary separation, and then the nano-sized (Cu, Mn)-rich phase was further separated from the dendrites in the secondary separation process. Hierarchical porous structures were prepared by etching the Cu–Fe–Mn composite coating. This work provides an important insight into the structural evolution and etching mechanism of the laser cladded Cu–Fe–Mn composite coating.