Journal of Materials Research and Technology (Jul 2024)

The influence of Mg/Al ratio on the cracking resistance of Zn–Al–Mg coatings

  • Ziyue Zhang,
  • Jie Zhang,
  • Xingyuan Zhao,
  • Kai Wang,
  • Xin Liu,
  • Shiming Li,
  • Sheming Jiang,
  • Xuequn Cheng,
  • Xiaogang Li,
  • Qifu Zhang

Journal volume & issue
Vol. 31
pp. 2508 – 2516

Abstract

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Galvanized steel plates with Zn–Al–Mg coatings are extensively utilized due to their exceptional corrosion resistance. This study, focusing on the cracking behavior of coatings with varying Mg/Al ratios, was conducted using in-situ tensile tests on different samples. The influence of the Mg/Al ratio on the crack resistance of the sample coatings was systematically summarized. To elucidate this point, five types of Zn–Al–Mg coatings with varying Mg/Al ratios were prepared using the same galvanizing process and tensile testing performed using a scanning electron microscope equipped with in-situ tensile capabilities. Macroscopic digital image statistical techniques were employed to quantify the extent of coating cracking, demonstrating the impact of the Mg/Al ratio on the coatings' crack resistance. The findings suggest that an increase in the Mg/Al ratio deteriorates the crack resistance of the coating, while enhancing its hardness. Moreover, this research offers a novel perspective in evaluating the crack resistance of coatings by comparing the effects of different Mg/Al ratios.

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