Corrosion Properties of the β-Mg₁₇Al₁₂ Phase in NaCl Solutions

Abstract

Polarization tests of the β-phase (Mg₁₇Al₁₂) in Mg–Al alloys were conducted using a 0.1 M NaCl solution (pH 11); E_corr of the β-phase was −1.377 V. When Ag or Zn was added to the β-phase, E_corr increased depending on the standard potential of the additive elements. However, the additive elements showed no significant difference in passive behavior during the test. This suggested that the additive elements did not affect the dissolution of the protective surface film. The same polarization test was conducted on pure Mg, and the results were compared with those of the β-phase. The anodic regions of the two polarization curves had different profiles. It was confirmed that the protective surface films formed on the pure Mg and β-phase had different properties.

Fig. 7 Polarization curves of single β samples measured in 0.1 M NaCl (pH 11) solution at 298 K.