Reduction of Nitrate Ion on the Growing Surfaces of Cr Nuclei Formed During Black Chromium Electrodeposition

In chromium electrodeposition, as with other metals, it is possible to obtain differences in coloration, whether it is black or white chromium. Both films have been obtained using two very similar baths, except that black chromium has KNO3 in solution. We found that the electrochemical deposits of both kinds of Cr follow a diffusion-controlled nucleation and growth mechanism of 3D centres. In fact, while white chromium exhibited a simple 3D nucleation mechanism, the black chromium was found to be complicated by the concurrent nitrate ions- reduction processes on the surface of recently formed Cr nuclei