DROSS PHASES FORMED IN GALVANIZING BATHS CONTAINING (0-0.1)WT-PERCENT NICKEL AT 450-DEGREES-C

The structure and composition of the intermetallic dross phases formed in zinc baths containing (0-0.1) wt% nickel at 450-degrees-C have been investigated by X-ray diffraction and energy dispersive spectroscopy. Two intermetallic phases were identified and the presence of each of these phases depends on the nickel content of the bath. Zeta (isomorphous with FeZn13) phase, which probably contains less than 0.5 wt% nickel, was the intermetallic phase present in baths with bath nickel contents of less than 0.06 wt%. In baths containing (0.06-0.09) wt% nickel both zeta and GAMMA2 (isomorphous with FeZn4) phases were present. When the bath nickel content was above 0.06 wt%, the nickel content of the zeta phase was found to increase significantly whilst the nickel content of the GAMMA2 phase only increased slightly with increasing bath nickel content. When the bath nickel content was above 0.09 wt%, the intermetallic phase was found to be mainly GAMMA2. Based on the experimental data, a more precise verision has been proposed for the zinc-rich corner of the Zn-Fe-Ni phase diagram at 450-degrees-C.