(1. 中南大学材料科学与工程学院，长沙 410083；
2. 中国电子科技集团第十八研究所，天津 300381)
摘 要: 利用扫描电镜(SEM)、X射线衍射(XRD)等检测分析稀土元素La对Mg-6%Al-5%Pb(AP65)镁合金(质量分数)显微组织的影响，并采用恒电流法、动电位极化扫描法和析氢法研究La含量对AP65镁合金的腐蚀电化学性能的影响。结果表明：加入La能够使AP65镁合金α-Mg组织得到细化，生成针状稀土相Mg80(Al,La)17和块状稀土相Mg17(Al,La)12；添加La提高了AP65镁合金的电化学活性、耐腐蚀性能和阳极效率，使AP65的平均电位负移；当La含量为2%(质量分数)时，平均电位最负为-1.73V(vs SCE)。添加6%La使AP65镁合金的平均析氢速率从1.75mL/(cm2·h)下降到0.02mL/(cm2·h)，并且使阳极效率从74.30%上升到82.31%。
关键字: AP65镁合金；La；显微组织；耐蚀性；电化学性能
（1.School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. The 18th Research Institute of China Electronics Technology Group, Tianjin 300381, China）
Abstract:The microstructures of Mg-6%Al-5%Pb (AP65) alloys (mass fraction) modified by La were investigated by SEM and XRD. The influence of La on the corrosion property of AP65 alloyswere examined by galvanostatic tests, potentiodynamic polarization and hydrogen generation tests. The results show that La addition in AP65 alloys can sufficiently refine α-Mg grain. Net-like phases Mg80(Al,La)17 and massive phases Mg17(Al,La)12 form in AP65 alloys. The La addition improves the electrochemical activity,corrosion resistance and anode efficiency of AP65 alloy. The mean electrode potential of the AP65 alloy shifts negatively with the addition of La. The most negative mean potential of -1.73VSCE occurs in the Mg-6%Al-5%Pb-2%La alloy. The hydrogen generation rate decreases from 1.75 to 0.02mL/(cm2·h)and the anode efficiency increases from 74.30% to 82.31% by adding 6%La to AP65 alloy .
Key words: AP65 Mg alloy; La; microstructure; corrosion resistance; electrochemical property
