Function and mechanism of supercritical carbon dioxide emulsified electrolyte in nickel electroplating reaction

►How does supercritical CO2 emulsion (Sc-CO2-E) influence on electroplating? ►Additive-free Watts bath was used to study sole-effect of Sc-CO2-E. ►The grain refinement is caused by periodic plating characteristic with Sc-CO2-E. ►The smoother surface is caused by improved homogenous reaction Sc-CO2-E. ►A model is proposed to demonstrated effects of Sc-CO2-E on electroplating.