Improving wear and corrosion resistance of LDEDed CrFeNi MEA through addition of B and Si

In this paper, a novel CrFeNiB0.03Si0.03 medium entropy alloy (MEA) coating was developed by utilizing Ni-base alloy powder NiBSi in place of pure Ni powder through laser direct energy deposition (LDED) technology. The study explores the improvement of wear and corrosion resistance of CrFeNi MEA coatings by incorporating B and Si elements. The results show that the addition of B element generates Cr and Fe boride phases, while Si element solidly dissolves in FCC phase. Compared to CrFeNi MEA, CrFeNiB0.03Si0.03 MEA exhibits doubled microhardness reaching 403 HV0.2 and a reduced wear rate by 40 %, attributed to fine microstructure and solid solution strengthening of Si. The corrosion resistance of CrFeNiB0.03Si0.03 is also improved compared to CrFeNi, which is due to the formation of more Cr2O3 in the corrosion layer and the formation of SiO2 network, which prevents cracks and holes in the embroidery layer and makes the corrosion layer denser.