Corrosion behaviour of recycled magnesium AZ91

Due to the increasing interest in light-weight materials, magnesium and its alloys have come under growing focus, particularly in respect to automotive applications. However, in order for magnesium alloys to be commonly used as a structural material, the problem of recycling should be addressed. One of the major problems in using recycled magnesium alloys is their poor corrosion resistance. The objective of this study was to determine and better understand the corrosion behavior of recycled magnesium alloys and to find a criteria for estimating the level of non-metallic inclusions in the alloy. The paper will emphasise the role of non-metallic inclusions and heavy elements on the mechanism of the corrosion process. The corrosion resistance was measured under salt spray, humidity and immersion test conditions as well as under potentiodynamic polarisation analysis in NaCl and Mg(OH)(2) electrolyte. The microstructure examinations were conducted using SEM electron microscope. The recycling processes were based on the combination of flux and fluxless methods and deposition techniques. The relation between microstructure and corrosion performance of the recycled materials will be discussed in details.