REACH compliant coatings as alternative to hard chromium

Electroplating plays a significant role in the surface finishing industry in Europe. However, the inclusion of Cr6+ and  boric acid in the Substances of Very High Concern (SVHC) list has necessitated the development of alternative  chemistriessuch nanocomposite coatings with excellent mechanical, tribological, and aesthetic properties. 

In this study, a comprehensive investigation was conducted to evaluate the use of various acids as substitutes for boric acid in nanocomposite electrolytes. The electrolytes contained 10g/L of SiC nanoparticles with diameter of around 200nm. A Hull Cell study was performed to determine the optimal current densities for each bath. The electrochemical properties of the baths were characterized using cyclic voltammetry (CV) and chronocoulometry. The morphology and structure of the resulting coatings were examined using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray fluorescence (XRF). Furthermore, the Vickers hardness of the coatings was measured. The optimal coatings exhibited a SiC codeposition rate of approximately 12% by weight and a hardness of approximately 1000 HV.