ZN-MN ALLOY ELECTRODEPOSITION ON STEEL

Electrodeposition of Zn-Mn (0 divided by 50 w/o) onto carbon steel she et and wire is discussed in the present paper. An original bath is pro posed and effects of stabilisers are studied. Baths and deposits are s tudied from the electrochemical and structural points of view. Electro chemical investigations include galvanostatic and potentiodynamic stud ies carried out in laboratory cells under natural and forced (rotating disk electrode) convection and a wire-plating pilot plant. Structural and compositional investigations include X-ray diffraction analyses, scanning electron imaging and energy dispersive analyses on steel shee t and wire. Electrochemical data can be correlated with alloy composit ion (limiting currents and how they are affected by mass transport con ditions), morphological results (lamellar low-Mn vs. globular high-Mn) and crystallographic (metastable epsilon monophasic deposits in the h igh-Mn range, polyphasic low-Mn coatings) structure, the variables whi ch have a bearing on functional properties of the coatings.