Microstructural analysis of low Ni content Zn alloy electrodeposited under applied magnetic field

The codeposition behaviour of Zn and Ni has been studied in sulphate electrolytes in presence of a superimposed magnetic field up to 1 T parallel to the surface. Structural analysis by X-Ray diffraction (XRD) method revealed that the alloys consisted of a mixture of zinc, η-phase and γ-phase. The results showed that the magnetic field B was responsible for variations of the alloy structural parameters (lattice imperfection and texture) for low pH. When the pH of electrolyte was increased, the effect of the magnetic field was erased. It was suggested that the preferential growth direction of Zn–Ni alloy was induced by the mass-transport enhancement of H+ ions promoted by B which induced an increase of the pH near the cathode. Then, for high value of pH up to 3.5, the crystallographic orientation (101) of Zn was always favoured to the prejudice of the Ni5Zn21 phase.