Regulating the localized corrosion of grain boundary and galvanic corrosion by adding the electronegative element in magnesium alloy

• Published in: Corrosion science 2025-03, Vol.244, p.112667, Article 112667
• Main Authors: Yan, Qixin, Hou, Lifeng, Sun, Junli, Li, Donghu, Song, Jianlei, Liu, Xiaoda, Wang, Qian, Wei, Yinghui
• Format: Article
• Language: English
• Subjects: Electronegativity; Germanium; Grain boundary; Mg alloys; Micro-galvanic corrosion
• ISSN: 0010-938X
• DOI: 10.1016/j.corsci.2024.112667

Strength-corrosion trade-off greatly inhibits the development of magnesium alloys. Here, we leveraged the electronegativity difference between alloying elements and Mg on atomic polarity to generate intermetallic containing electronegative atoms which could interact with electropositive H atoms in polar water molecules through Coulomb interaction, thus inhibiting H* desorption and micro-galvanic corrosion. Taking highly electronegative germanium (Ge) as an example in this study, it was demonstrated that the stable intermetallic Mg₂Ge stably suppressed grain boundary corrosion and corrosion current growth, reducing the longitudinal corrosion depth of Pure-Mg by approximately half. This study provided a corrosion resistance enhancement strategy based on electronegativity. •The variation of localized corrosion current density on the surface of Mg-Ge alloys was characterized in situ.•The stable inhibition of micro-galvanic corrosion by Mg2Ge at the microscale was demonstrated through SVET and analysis of grain boundary corrosion.•The Coulombic interaction between electronegative alloy atoms and electropositive hydrogen atoms in polar water molecules was considered.