Effect of natural and magnetic convections on the structure of electrodeposited zinc–nickel alloy

• Published in: Applied surface science 2009-06, Vol.255 (18), p.8048-8053
• Main Authors: Levesque, A., Chouchane, S., Douglade, J., Rehamnia, R., Chopart, J.-P.
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Electrodeposition; Exact sciences and technology; Magnetic field; Magnetoelectrochemistry; Magnetohydrodynamics; Physics; XRD; Zn–Ni alloy
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2009.05.012

The effects of a magnetic field applied in a direction parallel or perpendicular to the cathode substrate plane, during electrodeposition process of Zn–Ni alloy have been investigated by means of chronoamperometric measurements, X-ray diffraction and EDX analysis. The modification of crystal orientation of the alloy by the superimposition of a high magnetic field is discussed for alloys with a content of nickel range 6–13 at%. Whatever the phase composition obtained without magnetic field, either γ-Ni 5Zn 21 or a mixture of the γ and zinc phases, which depends on the concentration of Ni 2+ in the electrolyte bath, the preferential orientation (1 0 1) of the zinc phase is always favoured with perpendicular and parallel magnetic field. There is no saturation of this effect with amplitude of B up to 8 T. A study of different geometric configurations of the cathode, which induce more or less natural convection, consolidates these results. The structural modifications of Zn–Ni alloy electrodeposits are thus probably due to a magnetohydrodynamic effect. An additional phenomenon is observed in presence of a perpendicular applied magnetic field since the (3 3 0) preferential orientation of the γ-Ni 5Zn 21 disappears with high values of B.