The Effect of Al and Sn Additions on Corrosion Behavior of Permanent Mold Casting Magnesium Alloy

Abstract

In this study, the influences of aluminum and tin additions (individual and combined) on corrosion behavior of magnesium alloy have been determined. The studied alloys were fabricated by permanent mold casting method to measure the corrosion properties, a potentiodynamic test, hydrogen evolution test and immersion test were carried out in a 3.5% NaCl solution at pH 7.2. From the results of microstructure analysis, the Mg-9Al-1Zn alloy was found to be composed of α-Mg and rod-like Mg 17 Al 12 phase and the Mg-5Sn-5Al-1Zn alloy was found to be composed of α-Mg, rod-like Mg 17 Al 12 and Mg 2 Sn phases. In the case of the Mg-9Sn-1Zn alloy, the microstructure was composed of α-Mg and eutectic Mg 2 Sn phase. With Sn addition (individual and combined), the corrosion resistance of the Mg alloys improved.

Comparison of Electrochemical Corrosion Properties of Permanent Mold Casting GZ21 Alloy and AZ91 Alloy

“…하지만 마그네 슘 합금의 내식성을 향상시키는 방법에는 (1) α-Mg과 갈바닉 부식을 유발하는 Mg 17 Al 12 상을 억제하는 방법과 (2) Ca, Li 등의 원소를 첨가하여 Mg 부식과정에서 생성되는 Mg(OH) 2 피막을 안정화 시키는 방법 등이 보고 되고 있으나, 아직 많 은 연구가 필요한 실정이다 [6,11]. 최근 수행된 Mg-xSn 이원계 합금의 부식 특성 분석에 관 한 결과는 결정립계에 형성된 Eutectic Mg/Mg 2 Sn 상의 계 면에서 부식이 우선적으로 진행됨으로써 합금의 내식성을 상 당히 향상시켰다 [7][8][9]. [14].…”