采用电化学测试法、浸泡实验法以及表面形貌观察法研究了 Mg-Al-Pb和Mg-Al-Pb-Zn合金在3.5% NaCl溶液中的腐蚀行为.结果表明:两种合金的腐蚀过程中都存在一个腐蚀速率很低的孕育期,长时间浸泡后合金的腐蚀达到稳定状态.对于固溶处理的合金,腐蚀起始于晶界处,Zn的添加会抑制Mg-Al-Pb合金在孕育期内的腐蚀,但是在浸泡较长时间后反而会加速其腐蚀过程.对于铸态合金,腐蚀过程起始于第二相周围,并且在浸泡较长时间后第二相会对腐蚀起到阻碍作用.经过长时间的浸泡后, Mg-Al-Pb和Mg-Al-Pb-Zn合金的腐蚀达到稳定状态,此时氢气析出速率会随着腐蚀合金表面粗糙度的增加而线性增加.%The corrosion behavior of Mg-Al-Pb and Mg-Al-Pb-Zn alloys in 3.5% NaCl solution was investigated by electrochemical measurement ,immersion test and corrosion morphology observation . The results indicate that there is an incubation period at the corrosion onset during which the corrosion rate is low . Thereafter ,the corrosion comes into steady state ,especially after long time immersion .For the solution treated (T4) specimens ,the corrosion takes place along the grain boundaries and is first inhibited by zinc in incubation period of time and then accelerated also by the zinc after the incubation and long time immersion .For the as-cast specimens ,the corrosion was initiated around the second phases ,which hinder the corrosion when immersed for a long time .The hydrogen evolution rate of both Mg-Al-Pb and Mg-Al-Pb-Zn alloys increases linearly with the increasing surface roughness of the corroding alloys after long time immersion when steady state has been established .
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