Understanding corrosion via corrosion product characterization: II. Role of alloying elements in improving the corrosion resistance of Zn-Al-Mg coatings on steel

作者：Volovitch P^*; Vu T N; Allely C; Aal A Abdel; Ogle K

来源：Corrosion Science, 2011, 53(8): 2437-2445.

DOI：10.1016/j.corsci.2011.03.016

• Metal coatings
• Zinc
• Aluminium
• Magnesium
• Atmospheric corrosion
• De alloying

Corrosion products are identified on Zn, ZnMg and ZnAlMg coatings in cyclic corrosion tests with NaCl or Na2SO4 containing atmospheres. For Mg-containing alloys the improved corrosion resistance is achieved by stabilization of protective simonkolleite and zinc hydroxysulfate. At later stages, the formation of layered double hydroxides (LDH) is observed for ZnAlMg. According to thermodynamic modeling, Mg2+ ions bind the excess of carbonate or sulfate anions preventing the formation of soluble or less-protective products. A preferential dissolution of Zn and Mg at initial stages of corrosion is confirmed by in situ dissolution measurement. The physicochemical properties of different corrosion products are compared.

• 出版日期2011-8