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

• Published in: ISIJ International Vol. 61; no. 3; pp. 929 - 936
• Main Authors: Konishi, Takeshi, Sawada, Hideaki, Doi, Takashi, Ushioda, Kohsaku
• Format: Journal Article
• Language: English
• Published: The Iron and Steel Institute of Japan 15.03.2021
• Subjects: crystal structure; Fe2Al5; first principles calculation; molten zinc; partially occupied Al sites; synchrotron; top dross; X-ray diffraction
• ISSN: 0915-1559; 1347-5460
• DOI: 10.2355/isijinternational.ISIJINT-2020-428

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