Morphology and phase composition of Ni-Co alloy powders electrodeposited from ammonium sulfate-boric acid electrolyte
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In this paper the morphology of Ni-Co powders electrodeposited from ammonium sulfate-boric acid containing electrolyte is investigated as a function of alloy powder composition. Composition of the electrolyte, i.e. the ratio of Ni2+/CO2+ concentration is found to influence both, the alloy phase composition and the morphology of Ni-Co alloy powders. At the highest ratio of Ni2+/Co2+ ions concentration, typical 2D fern-like dendritic particles were obtained. With decrease of Ni2+/Co2+ ions ratio among 2D fern-like dendrites, 3D dendrites and different agglomerates of a size of about 100 mu m, being either compact (typical for pure Co powder) or composed of a large number of small 3D dendrites on their surface were obtained. According to the X-ray analysis, with decreasing Ni2+/Co2+ concentration ratio the amount of f.c.c. beta-Ni phase was found to decrease, while the amount of h.c.p. alpha-Co phase was found to increase being accompanied by the appearance of the f.c.c. Co phase at Ni2+/...Co2+ = 0.33.
Keywords:2D fern-like dendrites / 3D dendrites / agglomerates / f.c.c. beta-Ni phase / f.c.c. Co phase / h.c.p. alpha-Co phase / Ni-Co powders
Source:Materials Science Forum, 2006, 518, 307-312
- Recent Developments in Advanced Materials and Processes, 7th Conference of the Yugoslav-Materials-Research-Society (Yu-MRS), Sep 12-16, 2005, Herceg Novi, Montenegro