Gd、Y 对ZK60 镁合金腐蚀行为的影响

通过盐雾腐蚀实验并结合SEM和XRD分析,研究了稀土元素对锻造态ZK60镁合金腐蚀行为的影响.结果表明,ZK60合金耐蚀性较差,而在ZK60中添Gd、Y后的合金,其耐蚀性明显提高.腐蚀时间相同时,两种合金的微观腐蚀形貌不相同,ZK60合金腐蚀坑的形成时间较早(14 d),而添加Gd、Y后的ZK60合金腐蚀坑的形成时间较晚(21 d),添加Gd、Y后ZK60合金的腐蚀产物相对致密.两种镁合金的腐蚀产物均为Mg(OH)2,Mg(OH)2腐蚀产物膜极易发生开裂,形成网块状的腐蚀产物膜.腐蚀产物膜的进一步生长、开裂和脱落,加速了材料的腐蚀流失.

Influence of Gd,Y on Corrosion Behavior ofZK60 Magneisum Alloy

Effect of rare earth element Gd and Y on the corrosion behavior of ZK60 magnesium alloy was investigated in 5 wt% NaCl aqueous solutions with immersion test.The corrosion products and their morphologies formed in the solution after immersing various time have been analyzed by SEM and XRD.Results indicate that ZK60 magnesium alloy exhibits bad corrosion resistant behavior,while the corrosion resistant behavior of ZK60 alloy with the addition of Gd and Y is significantly improved.This phenomenon is ascribed to the fact that addition of Gd and Y can reduce the corrosion velocity of magnesium matrix.The corrosion morphology of the two kinds of magnesium alloys is different.The formation rate of the corrosion pit was decreased by the addition of Gd and Y.In addition,the corrosion product of ZK60 alloy with the addition of rare earth element is more condensed.The corrosion product is Mg(OH)2 for the two kinds of alloy,which is easy to split and the resultant result is the formation of net film.This film can further grow,split and fall off.At last,the corrosion process is accelerated.