J Shanghai Jiaotong Univ Sci

Journal of shanghai Jiaotong University (Science) ›› 2012, Vol. 17 ›› Issue (6): 663-667.doi: 10.1007/s12204-012-1342-5

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Microstructure of Hot-Dip Galvanized Zn-Al-Mg Alloy Coating

Microstructure of Hot-Dip Galvanized Zn-Al-Mg Alloy Coating

YU Kang-cai1,2 (余康才), LI Jun2* (李俊), LIU Xin2 (刘昕), LI Jian-guo1 (李建国), XUE Xiao-huai1* (薛小怀)   

  1. (1. School of Materials Science and Engineering, Shanghai Jiaotong University, Shanghai 200240, China; 2. Baoshan Iron & Steel Co. Ltd., Shanghai 201900, China)
  2. (1. School of Materials Science and Engineering, Shanghai Jiaotong University, Shanghai 200240, China; 2. Baoshan Iron & Steel Co. Ltd., Shanghai 201900, China)
  • Online:2012-12-31 Published:2012-12-30
  • Contact: LI Jun2* (李俊),XUE Xiao-huai1* (薛小怀) E-mail:xhxue@sjtu.edu.cn, lijun@baosteel.com

Abstract: The microstructure of hot-dip galvanized Zn-11%Al-3%Mg-0.2%Si alloy coating was studied in this article. X-ray diffraction analysis revealed the coating is composed by Zn, Al andMgZn2 phase. Optical microscope (OM) and scanning electron microscope (SEM) observations showed the coating is occupied by snowflake-like dendrite, double hexagonal organization and eutectic. The coating backbone was the dendrite considered to be a phase of hexagonal close-packed (HCP) structure judging form its morphology according to the crystal growth way in the coating. Transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS) researches on the dendrite suggested that an intermediate Zn-Al phase was formed at high temperature, then decomposed into a type of Zn-Al granular eutectoid after cooling down to room temperature, while the eutectoid Zn and Al had a certain crystallographic relationship. The coating solidification process and the grain crystal structure were discussed.

Key words: hot-dip galvanized coating| Zn-Al-Mg coating| dendrites| grain orientation

摘要： The microstructure of hot-dip galvanized Zn-11%Al-3%Mg-0.2%Si alloy coating was studied in this article. X-ray diffraction analysis revealed the coating is composed by Zn, Al andMgZn2 phase. Optical microscope (OM) and scanning electron microscope (SEM) observations showed the coating is occupied by snowflake-like dendrite, double hexagonal organization and eutectic. The coating backbone was the dendrite considered to be a phase of hexagonal close-packed (HCP) structure judging form its morphology according to the crystal growth way in the coating. Transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS) researches on the dendrite suggested that an intermediate Zn-Al phase was formed at high temperature, then decomposed into a type of Zn-Al granular eutectoid after cooling down to room temperature, while the eutectoid Zn and Al had a certain crystallographic relationship. The coating solidification process and the grain crystal structure were discussed.

关键词: hot-dip galvanized coating| Zn-Al-Mg coating| dendrites| grain orientation

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