STUDY ON ENHANCING THE HARDNESS AND WEAR RESISTANCE OF Zn–Ni ALLOY ELECTROPLATING COATINGS REINFORCED WITH GRAPHENE AND CARBON NANO TUBES

This study reported the fabrication of Zn–Ni alloy electroplating coatings reinforced with carbon nanomaterials (CNMs), namely carbon nanotubes (CNT) and graphene (Gr), to enhance their mechanical performance. The CNMs were functionalized with -COOH groups and uniformly dispersed into the electroplating bath to improve stability and prevent agglomeration. Electroplating was carried out on mild steel substrates at a current density of 2 A/dm², temperature of 45 °C, and plating time of 90 minutes, under continuous stirring to ensure homogeneous codeposition of CNMs. The resulting Zn–Ni/CNM composite coatings exhibited a 58.7% increase in hardness and a 4.47-fold improvement in wear resistance compared with conventional Zn–Ni coatings. These remarkable enhancements were attributed to the intrinsic mechanical properties of CNMs and their synergistic role in grain refinement, microstructural stabilization, and defect regulation within the metallic matrix.