Corrosion of Composite Ferro-Niobium Layers in Cobalt Matrix
Abstract
The ferro-niobium composite layers in cobalt matrix were obtained by cathode depositing from electrolyte solutions on steel base. The electrolyte included in its composition cobalt sulphate and cobalt chloride, boric acid was also added for pH stabilization. The ferro-niobium, powder with granulation smaller than 5 μm, niobium content of 98% and 2% iron, were introduced into the electrolyte with 20 g/L concentration. Electrodepositing was performed at different current densities: 615 A/m2, 570 A/m2, 458 A/m2 and the result was layers of cobalt and composite from ferro-niobium particles in cobalt matrix, with thickness varying between 50-90 μm. Corrosion resistance was assessed by linear voltammetry test watching the corrosion behavior depending on composition and structure of deposited layers. The potentiodynamic polarization curve was analysed for composite layers compared with cobalt layers. From Tafel curves was determinated the corrosion rate for each type of coatings.
References
[2]. E. Rudnik, L. Burzyńska, W. Jakubowska, Codeposition of SiC particles with cobalt matrix, Journal of Achievements in Materials and Manufacturing Engineering 41/1-2 (2010) 195-199.
[3]. L. Balint, T.Radu, O. Mitoseriu, S. Balint, A. Doniga - Ferroniobium composite coatings in cobalt matrix on steel support, obtained by electrochemical deposition Proceedings of the International Metallurgy and Materials Congress, may 2000, Istanbul, Turkey.
[4]. Lucica Balint, Simion Balint, Florentina Potecaşu - Soft magnetic composite by ferrotitanium particles in cobalt matrix, International Conference on Materials Science and Engineering 24-26 February 2005, Brasov – Romania, p. 97.
[5]. L. Balint, S. Balint, T. Radu, E. Stratulat - Analysis of diffusion processes at interface cobalt –steel sheets, The Annals of ‘Dunarea de Jos’ University of Galaţi, Fascicle IX. Metallurgy and Material Science, 2003, no. 2, p.78-84.
