Corrosion behaviour of magnesium alloys in chloride medium

Abstract

Magnesium and its alloys find wide application as sacrificial anode in cathodic protection of pipelines and burried structures where hot zones exist. Magnesium alloys containing different alleging elements, such as Sn, Cd and Zn were cast in the form of rod of dia. 1/2" and studied potentiodynamically and galvanostatically. PARC-273 was used for the polarization studies. OCP,E-corr and I-corr were measured. The total immersion test was also carried out to record weight loss. It was observed that alloy containing Cd and Zn showed higher corrosion rate in comparison to other alloys studied under identical conditions. Addition of Sn to the alloy improves the corrosion resistance properties marginally. Magnesium alloy containing Sn and Cd only was found to have superiority over other alloys in respect to corrosion resistance properties. The weight loss data substantiate the polarization data. The data are discussed in detail in the paper.