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/Si3N4 HEA nanocomposites were electro-co-deposited in an aqueous solution with varying loadings of Si3N4 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 Si3N4 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-Si3N4-40 mA/cm2 and HEA-6 g/L-Si3N4-40 mA/cm2 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 Si3N4 nanoparticles, which is a very promising approach for the surface protection of engineering materials used in corrosive and frictional-working conditions.