Microstructures, physical and corrosion behavior of NiCoFeCu high-entropy alloy nanocomposite coatings electro-co-deposited with nano-Si3N4 particles

High-entropy alloys (HEAs) have gained increasing attention over the decades, owing to their distinctive properties. Electrodeposition stands out as a cost-effective and convenient method for producing diverse types of HEAs. However, there's little attention paid to fabricating ceramic-enhanced HEA composites. In this study, NiFeCoCu/Si 3 N 4 HEA nanocomposites were electro-co-deposited in an aqueous solution with varying loadings of Si 3 N 4 nanoparticles and current densities. The morphological, elemental, and phase-structure characteristics were investigated using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD) techniques. The Vickers-microhardness measurements, reciprocal wear, and electrochemical tests were conducted to evaluate the physical and anti-corrosion performance of the composite coatings. The findings indicate that the incorporation of Si 3 N 4 nanoparticles not only changes the surface morphologies, compositions, and textures of the HEA matrix but also significantly enhances both the wear and anti-corrosion performance in artificial water by refining the microstructures and reducing the defects of the composite coatings. The HEA-3 g/L-Si 3 N 4 -40 mA/cm 2 and HEA-6 g/L-Si 3 N 4 -40 mA/cm 2 composite coatings demonstrate the best wear performance and anti-corrosion properties among the samples investigated, respectively. The present study shows a significant improvement in the mechanical and anti-corrosion properties of HEA coatings by incorporation of Si 3 N 4 nanoparticles, which is a very promising approach for the surface protection of engineering materials used in corrosive and frictional-working conditions.