Electrodeposition of Ni-Co Alloys. Determination of Properties to be Used as Coins

摘要

Our purpose is to look for new materials of Ni, Co and their combination, useful for blanks for coins. Thus, the objective is to change the old techniques in the fabrication of blanks, of higher cost, by direct current methods. On the subject suitable material for circulating coins, we focused on the synthesis of new alloys of NiCo over brass, by potentiostatic methods, studying the physicochemical and mechanical properties. Ni_xCo_(100-x) alloys and pure Ni and Co, were electrodeposited over foil brass (CuZn) p.a (width: 0,03mm), by cyclic voltammetry (CV) and constant potential (CP). The measurements by spectrometry of X-Ray fluorescence (EDXRF), microprobe (EDS) and SEM, showed Ni_xCo_(100-x) alloys but Co enrichment with smoothed surface and a granular morphology. The material was also characterized by X-ray diffraction showing (fcc) and (hcp) phases in accordance with the Ni_xCo_(100-x) composition, and the surface hardness assay, roughness and conductivity tests were also performed, obtaining specific properties, suitable for a coinage materials.