Atmospheric corrosion of Zn-Al coatings in a simulated automotive environment

作者：Zhang, Xian^*; Wallinder, Inger Odnevall; Leygraf, Christofer

来源：Surface Engineering, 2018, 34(9): 641-648.

DOI：10.1080/02670844.2017.1305658

• Atmospheric corrosion
• NVDA tests
• Zn
• Al
• Galfan
• Galvalume
• chloride
• microstructure

Accelerated NVDA (VDA 233-102) tests were performed on bare Zn and Al sheets, Galfan coating (Zn-5 wt-% Al) and Galvalume coating (Zn-55 wt-% Al) on steel. ZnO, Zn(OH)(2) and Zn-5(OH)(8)Cl-2 center dot H2O were the main corrosion products identified on both bare Zn sheet and Galfan. AlOOH and Al(OH)(3) were preferentially formed on bare Al sheet and Galvalume. In addition, Zn-Al-containing corrosion products, Zn6Al2(OH)(16)CO3 center dot 4H(2)O and/or Zn2Al(OH)(6)Cl center dot 2H(2)O were identified on both Galfan and Galvalume. Corrosion products of Zn6Al2(OH)(16)CO3 center dot 4H(2)O with a platelet morphology were preferentially formed in the zinc-rich interdendritic regions of the Galvalume surface. Galfan revealed a similar corrosion behaviour as bare Zn sheet, whereas Galvalume exhibited similar behaviour as bare Al sheet. Deposition of chlorides highly influenced the corrosion of both Galvalume and Al rather than Galfan and Zn due to the rapid local damage of the compact native thin film of Al2O3.

• 出版日期2018
• 单位武汉科技大学