Ignatova K.Lilova D.2024-07-162024-07-162024-07-162024-07-162016-01-011314-79781314-7471SCOPUS_ID:84964957739https://rlib.uctm.edu/handle/123456789/1132The kinetics of the electrodeposition of Cu and Co in Co-Cu alloy, chemical composition, cathodic current efficiency and morphology of Co-Cu alloys electrodeposited from an ammonia-sulphate electrolyte (AMSE) and from a weakly acidic citrate electrolyte (CE) without and with addition of saccharin (CE+SHR) at constant potential mode are compared. The results indicate that the deposition of Co-Cu alloys from AMSE occurs without initial polarization, while the deposition from CE is characterized by long initial polarization and the overall polarization is higher compared to that in AMSE as a result of formation of more stable citrate complexes of the metals. The individual deposition of Co as well as Cu from CE is a two-stage process of reduction of their complex ions. It is found that the Co-Cu alloys with Co up to 50 - 60 mass % deposited from AMSE have coarse-grained crystalline structure with comparable amount of elongated and spheroid crystals with average size in the range from 2 to 10 μm, as compared to those deposited from CE with average size of about and less than1μm. The increase of the Co content in the alloys up to 80 mass % results in decrease of the average size of the crystallites in AMSE to less than 5 μm, and in CE- of about 500 nm. The addition of saccharin in the citrate electrolyte yields glossy and smooth coatings with close to nano-sized structure with average size of the crystallites in the range from 100 to 300 nm.enArticle