Electrodeposition, characterisation and mathematical model of nickel–iron film in a parallel plate flow system

Authors: Yin, K.-M.; Huang, H. F.; Lin, Y. T.

Source: Transactions of the Institute of Metal Finishing, Volume 83, Number 2, April 2005 , pp. 82-90(9)

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Abstract:

Nickel–Iron alloy films were electrodeposited in a parallel plate flow system. The volumetric flow rate of electrolyte was fixed at 12 dm³ min^?1 through the 1 cm thick and 9 cm wide slit parallel plate. Fluid velocity was ca 0.22 m s^?1 under fully turbulent convective flow. Alloy films with iron content varying from 7·5 to 40 wt-% were deposited as a function of solution pH, temperature, bath ingredient concentration and applied current density. It is shown that the magnetic property is strongly correlated to the alloy content: the saturation moment, B_s, increases with the iron composition, while the coercivity, H_c, increases with nickel content. Current efficiency increases with pH and applied current density. The nickel deposition rate is inhibited in the presence of ferrous ion in the plating bath. The microhardness of the deposit is increased as the iron content is increased over the range studied. A mathematical model that considers the convective mass transfer of Fe(II) and Ni(II) species in the diffusion layer, the competition of adsorbed metal species on surface active sites, and Tafel electrochemical kinetics describe the alloy plating system well.Nickel–Iron alloy films were electrodeposited in a parallel plate flow system. The volumetric flow rate of electrolyte was fixed at 12 dm³ min^?1 through the 1 cm thick and 9 cm wide slit parallel plate. Fluid velocity was ca 0.22 m s^?1 under fully turbulent convective flow. Alloy films with iron content varying from 7·5 to 40 wt-% were deposited as a function of solution pH, temperature, bath ingredient concentration and applied current density. It is shown that the magnetic property is strongly correlated to the alloy content: the saturation moment, B_s, increases with the iron composition, while the coercivity, H_c, increases with nickel content. Current efficiency increases with pH and applied current density. The nickel deposition rate is inhibited in the presence of ferrous ion in the plating bath. The microhardness of the deposit is increased as the iron content is increased over the range studied. A mathematical model that considers the convective mass transfer of Fe(II) and Ni(II) species in the diffusion layer, the competition of adsorbed metal species on surface active sites, and Tafel electrochemical kinetics describe the alloy plating system well.

Keywords: PARALLEL PLATE; NICKE-IRON ALLOY; ELECTRODEPOSITION; MATHEMATICAL MODEL; MAGNETISM

Document Type: Research Article

DOI: http://dx.doi.org/10.1179/002029605X29401

Publication date: 2005-04-01

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