二段階溶融Zn-Alめっき鋼のめっき層組織とその形成挙動 [in Japanese] Structures and Formation Behavior of Coating Layer in Two-step Zn-Al Hot-Dipped Steel [in Japanese]
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Structures and its formation behavior of coating layer formed on steel by two-step hot-dipping method i e., primary dipping in a zinc bath followed by immersion in a secondary Zn-7 mass%Al bath, were studied using scanning electron microscope (SEM), electron probe micro-analysis (EPMA) and X-ray diffraction analysis (XRD). Primary dipping layers composed mainly of ζ phase and trace of η phase. The columnar structure changed to a fine acicular structure with a Fe<sub>4</sub>Al<sub>13</sub>-Zn<sub>x</sub> phase at temperatures below 693K. Above 703K, it became a two-phase structure of a plate-like Fe<sub>2</sub>Al<sub>5</sub>-Zn<sub>x</sub> and a fine broken acicular Fe<sub>4</sub>Al<sub>13</sub>-Zn<sub>x</sub> phase. A Zn-Al coating layer over 50μm thick was obtained by secondary immersion between 683K and 733K for steel dipped into a primary bath at 763K.
- Jitsumu Hyomen Gijutsu
Jitsumu Hyomen Gijutsu 48(9), 929-936, 1997-09-01
The Surface Finishing Society of Japan