ABSTRACT
The electrodeposition of copper on ferrous and non-ferrous substrates from solutions containing cyanide is one of the most used industrial forms. The deposits obtained by this process are of high quality with low operating cost, unsophisticated equipment and simple pre-treatment in the substrate. However, new cyanide-free electrolytes have emerged to replace cyanide solutions that are toxic and have a great potential to cause environmental and health damage. The objective of this work was to obtain electrodeposited copper (electrolytic Cu) by direct current from an ammonium sulfate and sodium citrate bath; and, evaluate its characteristics with those of commercial electrolytic copper (commercial Cu), as well as analyze two methodologies for preparing the metallic surface for analysis by microscopy. The characterization techniques used were X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Optical Microscopy (MO) and nano hardness, the sample surfaces were prepared by conventional and electrolytic polishing. It was observed that the electrolytically polished samples were very bright and showed the grain contours with greater clarity, the same results were not evidenced by conventional polishing. The copper obtained by the cyanide-free bath showed smaller grain sizes and a greater hardness inside them, when compared to commercial Cu. The diffractogram showed high intensity peaks for the electrolytic Cu in the planes (200) and (111) showing a greater preferential crystallographic orientation in the directions of these planes. Finally, the SEM showed a segregation of a phase in the electrolytic Cu, caused by the electrodeposition and also the shapes of the polygonal grains with globular microcavities of the commercial Cu.
Keywords
electrodeposited copper; electrolytic polishing; cyanide free bath
