Development of zinc oxide-rich inner layers in hot-dip zinc coating for barrier protection

The formation of ZnO composite-rich inner layers and its impact on the galvanization process and characteristics of hot-dip zinc coating were explored in the present study. Steel substrates were initially coated with a fragmented layer of ZnO and then subsequently galvanized. The presence of ZnO-rich inner layer influenced the galvanizing process substantially. The process resulted in the formation of more adherent layers with lower coating thickness. The presence of the inner oxide layer caused a modification of the inner alloy structure and the coating composition. The physical, mechanical as well as galvanic performance of the coating were also improved by the presence of the ZnO-rich inner alloy layers.