Hydrogen evolution, efficiency and exacerbated galvanic corrosion damage of magnesium alloy anode

Abstract

To address the galvanic corrosion issue that is critically limiting the practical application of Mg alloys, the negative difference effect (NDE), anodic dissolution efficiency, and anodic hydrogen evolution were investigated by means of the hydrogen collection, Mg wire array electrode, and surface microanalyses based on the model of monovalent Mg+ dissolution at film breaks. The results show that anodic hydrogen evolution is closely associated with the negative difference effect, while the micro-galvanic process of Mg is not responsible for the low anodic current efficiency, and the secondary effect of dissolved zinc ions can to some degree reduce the anodic current efficiency. The protectiveness of the surface film is the most important factor determining the current efficiency, anodic hydrogen evolution, and galvanic corrosion damage.

Keywords

• magnesium alloy
• hydrogen evolution
• negative difference effect
• anodic current efficiency
• galvanic corrosion