2019 年 105 巻 12 号 p. 1143-1152
In a molten zinc bath of a continuous galvanizing line, top dross particles crystallize as Fe2Al5 intermetallic compound containing Zn. These particles easily adhere to the steel sheets causing surface defects. Therefore, controlling the top dross particles is a key issue. The present study focused on the determination of facet plane of top dross using three-dimensional analysis of morphology of the top dross by simultaneous exploitation of the serial sectioning process and electron back scattering diffraction (EBSD). Furthermore, the crystallographic plane of the cleavage fracture surface of the top dross was determined by EBSD, after cleavage crack was introduced by Vickers hardness indentation. The following results were obtained: (1) The facet planes of the top dross consist of two planes of (001), four planes of {110} and eight planes of {111}. In addition, the top dross particles grow fastest in the [001] direction. Consequently, the top dross particle is concluded to have the polyhedron structure with 14 facet planes. (2) The cleavage fracture surface of the main crack in the top dross is (100) plane.