Influence of Addition of Ge on the Microstructure and Corrosion Properties of Magnesium

Abstract

The corrosion properties of Mg–xGe (x = 0, 0.5, 1.0, 1.5 and 2.0 mass%) alloys were investigated. Potentiodynamic polarization and electrochemical impedance spectroscopy tests were carried out in a 3.5% NaCl solution at pH 7.2 to measure the corrosion properties of Mg–xGe (x = 0, 0.5, 1.0, 1.5 and 2.0 mass%) alloys. Microstructural analysis showed that a Mg₂Ge phase formed mainly in the interdendritic areas. The volume fraction of the Mg₂Ge phase was increased with increasing Ge content. The corrosion resistance of the Mg–xGe alloys was improved by Ge addition. In particular, the Mg–1.5 mass%Ge alloy showed the superior corrosion resistance of the alloys examined.