Effects of saccharin on the electrodeposition of Ni–Co nanocrystalline coatings
- 473 Downloads
Nickel–Co nanocrystalline coatings were electrodeposited onto a carbon steel substrate with and without saccharin addition. In the absence of saccharin, current density and adsorption of hydrogen complexes and/or intermediate components were distinguished as two effective parameters causing nanocrystalline electrodeposits. In the latter case, the growth active sites can be blocked easily at low current densities. By increasing the current density, a lower degree of adsorption was associated by a significant increase in surface diffusion of adions resulting in grain growth. Although, the nucleation rate is expected to increase with current density, it seems that the Ni–Co grain size is not reduced by the nucleation rate. Adsorption of saccharin molecules and/or decomposed sulfide species occurred in the saccharin contained bath, resulting in slow surface diffusion of adions. Therefore, finer grains were obtained which produced a smooth morphology instead of the pyramidal forms obtained in the absence of saccharin.
KeywordsNi–Co Nanocrystalline coating EIS Electrodeposition Adsorption
- 16.Wu BYC (2002) Synthesis and characterization of nanocrystalline alloys in the binary Ni–Co system. B.Sc. thesis, University of TorontoGoogle Scholar
- 18.Cullity BD, Stock SR, Stock S (2001) Elements of x-ray diffraction. Addision-Wesley, LondonGoogle Scholar
- 19.Gabrielli C (1998) Identification of electrochemical processes by frequency response analysis. Technical Report No. 004/83, University of Pierre et Marie Curie, ParisGoogle Scholar
- 20.Schlesinger M, Paunovic M (2000) Modern electroplating. John Wiley & Sons, London, p 46Google Scholar