NUCLEATION AND GROWTH OF COPPER ON GLASSY-CARBON AND STEEL

The nucleation and growth of copper from sulphate solution have been s tudied on two substrates, glassy carbon and stainless steel. Investiga tions were performed by linear sweep voltammetry, potential and curren t step methods. The results suggest that a copper coating is formed on glassy carbon by three-dimensional nucleation and growth of the cryst allites up to coalescence. On steel, after the formation of crystallit es by the same mechanism as above, a second step was observed. The oxi de layer, which was on the parts of the substrate not covered by the f irst crystallites, was reduced, allowing copper to deposit on the rene wed surface by a non-nucleated process. This may explain the rapid cov ering of steel, as compared with the slow covering of glassy carbon, a nd the different morphology of the deposits obtained on the two substr ates.