Ce添加对AP65镁合金显微组织及电化学性能的影响

摘要

采用熔炼铸造法制备添加不同含量Ce的AP65镁合金。采用X射线衍射(XRD)、扫描电镜(SEM)和电子探针(EPMA)研究Ce对AP65镁合金显微组织的影响。采用恒电流放电、动电位极化扫描、化学浸泡研究不同Ce含量AP65镁合金的腐蚀电化学行为。结果表明：随Ce含量增加，合金中依次出现棒状或簇状的Al 4 Ce相和块状的Al 2 Ce相。Ce的添加导致AP65镁合金的电化学性能明显提高，添加0.6%(质量分数)的Ce使AP65镁合金的平均放电电位从−1.648 V(vs SCE)负移到−1.756 V(vs SCE)；添加4%的Ce使AP65镁合金具有较小的腐蚀电流密度(19.66μA/cm2)和较高的阳极利用率(84.3%)，与未添加Ce的AP65镁合金相比，阳极利用率提高16.6%。%AP65 magnesium alloys with different contents of Ce were prepared by melting and casting method. The effect of Ce on microstructures of these alloys was investigated by XRD, SEM and EPMA. The electrochemical corrosion behavior of AP65 magnesium alloy was studied by galvanostatic discharge, potentiodynamic polarization and immersion tests. The results show that the rod-like or cluster-like Al4Ce phases and the bulk Al2Ce phases exist in AP65 magnesium alloys with increasing the Ce content, leading to a great improvement of the electrochemical performance. The discharge potential of AP65 alloy isshifted from −1.648 V (vsSCE) to −1.756 V (vs SCE) after adding 0.6%Ce (mass fraction), while AP65 alloy with 4% Ce has the smallest corrosion current density of 19.66μA·cm−2 and highest anode utilization efficiency of 84.3% which is 16.6% higher than that of AP65 alloy without the addition of Ce.