Crystal Structure Analysis of Top Dross in a Molten Zinc Bath by First Principle Calculation and Synchrotron X-ray Diffraction

Abstract

In a molten zinc bath in a continuous galvanizing line, top dross particles crystallize as Fe₂Al₅ intermetallic compound containing Zn, which causes the surface defect of the final products by easily adhering to steel sheets. The present study focused on the analysis of crystal structure of the top dross by simultaneously exploiting first principle calculation and synchrotron X-ray diffraction of top dross prepared in a laboratory. The following results were obtained: The first principle calculation on top dross suggested that two Al atoms in the partially occupied four Al sites of Fe₂Al₅ based on the crystal structure proposed by Mihalkovič et al. were replaced by two Zn atoms. In addition, Al atoms in the two kinds of partially occupied Al sites in Fe₂Al₅ proposed by Burkhardt et al. was equally replaced by Zn atoms. The propose crystal structure of top dross was verified by the X-ray diffraction profile analysis using RIETAN-FP simulation as well as the experimentally determined lattice constant of Zn containing top dross.