REPUBLIC OF SERBIA

MINISTRY OF DEFENCE

www.mod.gov.rs

MINISTRY OF DEFENCE

Material Resources Sector

Defensive Technologies Department

Military Technical Institute

www.vti.mod.gov.rs

INTERESTING SURFACE MORPHOLOGY OF ZN-Mn ALLOY COATINGS rich in manganese

Mihael bučko

University of Defence, Military Academy, Belgrade, mihaelbucko@yahoo.com

jelena bajat

Faculty of Technology and Metallurgy, Belgrade, jela@tmf.bg.ac.rs

BOJAN JOKIĆ

Faculty of Technology and Metallurgy, Belgrade, bjokic@tmf.bg.ac.rs

SINIŠA B. Gačić

Technical Testing Center, Belgrade

Abstract: The manganese addition can significantly improve the corrosion resistance of sacrificial Zn coatings on steel. The best properties are obtained in the Zn-Mn alloys where Mn content is in the range of 30 – 40 atomic percent. The scope of this work was to, for the first time according to our knowledge, employ the electrolyte containing Zn and Mn chlorides, in electrodeposition of Zn-Mn alloys which would have high Mn content on one side, and satisfactory surface appearance and morphology on the another side. The alternation of two deposition parameters, namely, deposition current density and manganese ion concentration in the electrolyte, was investigated. The electrochemical reactions of interest were studied by cyclic voltammetry and chronoamperometry. The samples obtained were characterized by scanning electron microscopy and energy dispersive X-ray spectrometry. The coatings deposited at current densities higher than 200 mA cm^-2 have shown to be with smooth, homogeneous and bright surface.

Key words: Zn-Mn alloy, coating, electrodeposition, surface morphology.