CORROSION STABILITY OF ELECTROCHEMICALY DEPOSITIED Zn-Mn ALLOY COATINGS

Zinc al-loy co-a-tings elec-troc-he-mi-cally de-po-si-ted on steel from elec-trolytes with dif-fe-rent components dif-fer in the-ir com-po-si-tion, ho-mo-ge-ne-ity, po-ro-sity, struc-tu-re and other cha-rac-te-ri-stics that af-fect the-ir cor-ro-sion re-si-stan-ce. Man-ga-ne-se is cha-rac-te-ri-zed by a very ne-ga-ti-ve electrochemi-cal po-ten-tial and very high strength, promp-ting many researchers to study Zn-Mn alloys for the an-ti-cor-ro-sion pur-po-ses in the in-du-stry, especially auto-mo-ti-ve. In this work it was exa-mi-ned the in-flu-en-ce of the type of the electrolyte de-po-si-tion on the cur-rent ef-fi-ci-ency du-ring elec-tro-de-po-si-tion of Zn-Mn al-loys. Zn-Mn al-loys we-re de-po-si-ted on steel from chlo-ri-de, sulp-ha-te and pyrop-hosp-ha-te pla-ting baths at dif-fe-rent cur-rent den-si-ti-es. We ha-ve exa-mi-ned the in-flu-en-ce of de-po-si-tion cur-rent den-sity on the cur-rent ef-fi-ci-ency du-ring elec-tro-de-po-si-tion, ap-pe-a-ran-ce of alloy co-a-tings, as well as the-ir cor-ro-sion sta-bi-lity. It was shown that Zn-Mn al-loys with the best corrosion pro-per-ti-es, among all exa-mi-ned ones, we-re ob-ta-i-ned from chlo-ri-de pla-ting bath at 2 A dm-2.