Corrosion resistance of Mg-RE-Zr alloys

Purpose: Magnesium alloys are widely used in the automotive and aerospace industries. Data concerning corrosion of Mg alloys are numerous, but those concerning Mg-RE alloys are scarce. In this paper, the corrosion behavior of cast magnesium alloys containing rare earth elements (WE54, WE43 and Elektron21) were investigated by immersion test in 3.5% NaCl for times up to 7 days. Design/methodology/approach: The study was conducted on WE54, WE43 and Elektron 21 alloys in the ascast condition. Immersion test was performed using not deaerated 3.5% NaCl solution at room temperature. Several specimens were placed in 3.5% NaCl solution for periods of time between one and 7 days. The dissolution rates (mg/cm-2day-1) were determined by weight loss measurements. Findings: Elektron 21 alloy exhibits the highest corrosion rate during the immersion test, while WE54 and WE43 alloys had a similar corrosion behavior. The corrosion rates of WE54 and Elektron 21 alloys incresed lineally with increasing the exposure time in 3.5% NaCl, and that of WE43 was almost unchanged and finally reached maximum value 0.26 mg/cm-2day-1. Research limitations/implications: The knowledge about corrosion behavior of Mg-RE-Zr alloys is currently under evaluation on many speciality applications where lightweight connected with optimum corrosion resistance are required Practical implications: The comparative results of corrosion behavior of new Mg-RE-Zr alloys leads to optimum choice of alloy for application in automotive, aircraft and aerospace industries. Originality/value: This paper includes the comparative results of corrosion resistance investigations of new Mg-RE–Zr alloys.