Application of thermodynamics and Wagner model on two problems in continuous hot-dip galvanizing

Firstly in this paper, the influence of H-2 and water vapor content on selective oxidation occurred in continuous hot-dip galvanizing has been studied by thermodynamics and Wagner model, then, the Gibbs energy of each possible aluminothermic reducing reaction in zinc bath was calculated in order to judge the possibility of these reactions. It was found that oxides' amounts and oxidation type were greatly related to the H-2 and water content in the annealing atmosphere. And from the view of thermodynamics, surface oxides (MnO, Cr2O3, SiO2 etc.) can be reduced by the effective Al in Zn bath. (C) 2009 Elsevier B. V. All rights reserved.