Improved wear and corrosion resistance of laser-clad (Fe0.25Co0.25Ni0.25Cr0.125Mo0.125)86B14 coating through annealing treatment

Abstract

Phase separation and elemental segregation of the laser-cladded high entropy alloy (HEA) coating will affect their wear and corrosion resistance. In this study, (Fe0.25Co0.25Ni0.25Cr0.125Mo0.125)86B14 HEA coatings were prepared on 27SiMn steel through laser cladding. Considering the performance consistency of the coating at different annealing temperatures, the phase evolution, component distribution, gradient microstructure, and overall properties of the coating were investigated. Annealing can facilitate the diffusion of segregating elements (Mo, Cr, and B), which reduces the face-centered cubic (FCC) phase content and improve the formation of body-centered cubic lattice (BCC) phases in the coating. The phase composition of the coating does not undergo significantly changes before and after annealing at 600 and 1000 °C because of a lower driving force for element diffusion and the preferential formation of Fe23B6 precipitates. The coating annealed at 800 °C featured a BCC microstructure and a small portion of FCC with boride precipitates in its top and middle layers and an amorphous phase in the top layer. The top, middle, and bottom layers of the coating exhibited the lowest average friction coefficients of 0.3988, 0.3860, and 0.4005, wear volume losses of 0.39 × 108, 0.36 × 108, and 0.39 × 108 μm3, the highest Ecorr, and lowest Icorr, respectively. Notably, the coating annealed at 800 °C exhibited good consistency in wear and corrosion resistance from its top surface to the bottom.