Effect of solid solution Zn atoms on corrosion behaviors of Mg-2Nd-2Zn alloys

• Published in: Corrosion science Vol. 196; p. 110023
• Main Authors: Sun, Lingxiong, Dong, Ningning, Wang, Jinhui, Ma, Hongbin, Jin, Peipeng, Peng, Yong
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 01.03.2022; Elsevier BV
• Subjects: Corrosion; Corrosion behaviors; Corrosion effects; Corrosion products; Corrosion rate; Extrusion; Heat treatment; Magnesium base alloys; Oxidation; Scale (corrosion); Second phases; Solid solution atoms; Solid solutions; Solution heat treatment; Corrosion products; Second phases; Heat treatment; Solid solution atoms; Corrosion behaviors
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/j.corsci.2021.110023

The effects of heat treatments on the microstructures and corrosion behaviors of extruded Mg-2Nd-2Zn alloys in 3.5% NaCl electrolyte were investigated. It was found that the average corrosion rate of solid solution Mg-2Nd-2Zn alloy is 45.86 mm/y, which is much lower than that of the as-extruded and solution-aged Mg alloys. The nano-scale oxides were formed by the oxidation of solid solution atoms during the corrosion process and filled into the porous corrosion product film, which was conducive to reducing the corrosion rates of Mg alloys. Therefore, the solid solution treatment remarkably improved the corrosion rate of Mg alloys. •Heat treatments remarkably increase the grain sizes of Mg alloys and reduce grain boundary corrosion.•The corrosion products of Mg-2Nd-2Zn alloy are mainly composed of Mg(OH)2 and Mg2Cl (OH)3·4H2O.•Cl- attacks Mg(OH)2 to form loose Mg2Cl(OH)3·4H2O, resulting in a poor corrosion resistance of Mg alloys in Cl- solution.•Nano-scale oxides of solute atomic embedded in corrosion product film improves the corrosion resistance of Mg alloys.