The Electrochemical and Immersion Corrosion of Casting Magnesium Alloys Containing Rare Earth Elements

Magnesium alloys are widely used mainly in automotive and aerospace industries. There is quite a lot of information about corrosion of the magnesium alloys in available literature. However, the publications concern mainly Mg-Al alloys, while there is a lack of information about Mg-RE-Zr alloys. The following paper presents results of the investigations on the electrochemical corrosion of magnesium casting alloys containing rare earth elements (WE43, WE54, EV31A-Elektron 21) as well as pure magnesium. The alloys were investigated by immersion test in 3.5% NaCl for times up to 7 days. Electrochemical investigations were carried out at ambient temperature in aerated NaCl solution, using potentiodynamic polarization method. It has been shown that the best corrosion resistance is exhibited by alloys with yttrium addition (WE43, WE54), while the weakest by pure magnesium. EV31A alloy exhibits the highest corrosion rate during the immersion test, while WE54 and WE43 alloys had a similar corrosion behavior.