Investigation into fabrication and performance of carbon sol reinforced Cu composite coatings

This study successfully developed a series of carbon-sol reinforced copper (Cu-CS) composite coatings using electrodeposition with superiorly dispersed carbon sol to avoid nanoparticle aggregation. The carbon sol, characterized using transmission electron microscopy (TEM) and Zeta potential analyzer, consisted of carbon particles with an approximate diameter of 300 nm, uniformly distributed in the electrolytes. Characteristics of the composite coating were examined under scanning electron microscopy (SEM) observing its microstructures and X-ray diffraction (XRD) detecting the phase constituents. The sample's durability including wear resistance and corrosion resistance were also tested. Results indicate a significant improvement in coating thickness, density, and uniformity achieved for the Cu-CS composite coating at a carbon sol addition of 20mL/L. Moreover, it boasts a low wear volume (1.15×10-3 mm3), a high hardness (137.1 HV0.5), and a small corrosion rate (1.91×10-1 mm/year). The significant contribution of carbon particles in two factors improves the coating performance: strengthening effects and lubricating effects resulting from the incorporated carbon particles. Nevertheless, overdosage of carbon sol can compromise Cu-CS coating's microstructure, creating defects and undermining its functionality.