Influence of alloying elements on the structure and corrosion resistance of galvanized coatings

Abstract

61.10.Nz, 68.35.Fx, 68.37.Hk, 81.15.–z, 81.65.Kn Carbon steel samples were galvanized by the hot-dip method in zinc baths containing 0.5 or 1 wt% alumi-num, copper, tin, nickel, and/or lead. Bath temperature ranged from 450 to 480 °C. The samples were examined using optical microscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD). The influence of the alloying elements on the formation of the different phases and on the diffusion pro-cess is discussed. In order to study the kinetics and the mechanism of corrosion of these materials, corro-sion experiments were carried out in a simulated environment of accelerated atmospheric corrosion condi-tions, for which a special chamber (Salt Spray Chamber – Alternative Climate Test Chamber) of type SC-450 was used. The corroded samples were examined using optical microscopy, SEM and XRD. Chloride and oxide phases, which penetrated the materials to different depths from the surface, were revealed. Fi-nally, useful conclusions were drawn which help to control the factors of the corrosion behavior of the examined materials in a marine atmosphere.