Influence of Lanthanum concentration on the Corrosion Behaviour of Binary Mg-La Alloys

Different contents of Lanthanum have been added to Magnesium and have been investigated on their influence on the microstructure and the corrosion properties. The microstructure was studied by optical microscopy. Corrosion performance was evaluated using potentiodynamic polarization measurements. Immersion tests were carried out using distilled water and 0.1 M sodium chloride solution. The corrosion products were investigated by X-ray induced photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES) and X-ray diffraction (XRD) which lead to detailed information on phase formation. The oxide and hydroxide formation have been correlated to the chemical states and formed intermetallics, i.e by taking into account the XPS peak shift and peak splitting of the the Mg-2p state. Additionally, the results have been verified by means of AES on the Mg-KLL, O-KLL and La-MNN excitation and by XRD. Latter suggests the supplemental formation of a nanocrystalline phase.