1. Marija Riđošić, Tehnološki fakultet u Istočnom Sarajevu,
Republic of Srpska, Bosnia and Herzegovina
2. Katarina Crljenić, Tehnološki fakultet u Istočnom Sarajevu, Republic of Srpska, Bosnia and Herzegovina
3. Mihael Bučko, University of Defense, Military Academy, , Serbia
4. Milorad Tomić, Republic of Srpska, Bosnia and Herzegovina
5. Jelena Bajat, University of Belgrade, Faculty of Technology and Metallurgy, , Serbia
The nanocomposite coatings are novel type of materials which are composed of two or more components and at least one must be at nano scale. The nanocomposite coatings possess better properties compared to their micro versions and because of that this material found application in different industrial areas. The Zn-Mn coatings are already known as material with good corrosion properties. The aim of this work is to reinforce Zn-Mn alloy with Al2O3 nanoparticles to advance it corrosion properties. The main problem in deposition of composite coatings is low dispersion stability of plating solution and agglomeration of the particles in plating solution. Consequently it is hard to achieve the homogeneous distribution of the particles in the matrix which is connected to good properties of the final product. In literature there are different methods for de-agglomeration of the second phase in plating solution, like ball milling, mechanical or magnetic stirring etc. The ultrasound applied during the deposition is beneficial not only for deagglomeration phenomenon but also for advancing the properties of the coating. In this work the ultrasound assisted electrodeposition of Zn-Mn-Al2O3 nanocomposite coatings is performed galvanostatically by 1; 2 and 4 A dm-2 current densities. Electrodeposition is preformed from four different plating baths, R1 was without Mn2+ ions, and R2, R3, R4 was with different Zn2+: Mn2+ ions ratio. The deposition time was 15 minutes. Composition of the coatings was analyzed by electron dispersive spectroscopy and corrosion properties were analyzed by different electrochemical methods. Namely, the Tafel polarization method and electrochemical impedance spectroscopy were used for determination of corrosion stability of the obtained composite coating in 3.5wt% sodium chloride. The results show that Zn-Mn-Al2O3 composite coating had advanced corrosion stability in saline environment compared to Zn-Al2O3 coatings. The coating deposited with 4 Adm-2 from bath 2 (Zn2+:Mn2+ ratio 1:1) showed the lowest corrosion current density and the lowest corrosion rate in 3 % NaCl solution.
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