Effect of Nano-oxide addition on corrosion performance of hot dip zinc coating

Resumo

Corrosion performance of hot dipped zinc coating on low carbon steel was studied at the presence of different nanoand micronsize oxide particles in the liquid zinc bath. Nano-silica, nano-alumina and micro-alumina powders were loaded to the different liquid baths, in the range of 0.05–0.2 wt %. Low carbon steel specimens were immersed in the baths for a constant time of 10s. It was evident that the presence of oxide particles in the liquid bath increased the coating thickness at a constant immersing time; micro-alumina particles provided the thickest coating among the others. Salt spray and potentiodynamic polarization tests were conducted to evaluate corrosion performance of the galvanized coatings, including oxide bearing ones. The results confirmed improvement in corrosion resistance of the nano-oxide bearing zinc coatings; while incorporation of micro-alumina in the bath declined its corrosion resistance. It was shown that incorporation of nano-silica powder in the liquid bath yielded superior corrosion resistance of the zinc layer, in comparison to the other ones. The optimum corrosion performance of zinc coating was achieved via loading 0.1 wt % nanosilica to the liquid zinc bath in this work.