Electrospark alloying of Mg–La electrode on ZM5 Mg alloy under distilled water or kerosene

Abstract

The electrospark alloying (ESA) technique has been successfully applied to deposit an Mg–La layer on a ZM5 Mg–Al–Zn type Mg alloy at room temperature. The effect of Mg–La magnesium alloy on the coating layer formation with varying processing parameters was investigated. The effect of kerosene and distilled water as dielectrics on ESA of ZM5 alloy was studied. Optical microscopy and scanning electron microscopy equipped with energy dispersive X-ray analysis were used to study the microstructure and element distribution of the alloying layers. The distribution of the rare earth La in the coating layer was determined. It has been possible to obtain a fully dense and strongly adherent coating layer. The typical ‘splash’ appearance of the coating surface can be observed and is related to the mechanism of the consumable Mg–La electrode alloying technique.

Keywords:

• Magnesium alloy
• Lanthanum
• Spark alloying
• Corrosion

The authors would like to acknowledge the financial support of this research by National Nature Science Foundation of China (grant no. 50801050).