Ce添加對AP65鎂合金顯微組織及電化學性能的影響Effect of Ce addition on microstructure and electrochemical performance of AP65 magnesium alloy

采用熔煉鑄造法制備添加不同含量Ce的AP65鎂合金。采用X射線衍射(XRD)、掃描電鏡(SEM)和電子探針(EPMA)研究Ce對AP65鎂合金顯微組織的影響。采用恒電流放電、動電位極化掃描、化學浸泡研究不同Ce含量AP65鎂合金的腐蝕電化學行為。結果表明：隨Ce含量增加，合金中依次出現棒狀或簇狀的Al₄Ce相和塊狀的Al₂Ce相。Ce的添加導致AP65鎂合金的電化學性能明顯提高，添加0.6%(質量分數)的Ce使AP65鎂合金的平均放電電位從-1.648 V(vs SCE)負移到-1.756 V(vs SCE)；添加4%的Ce使AP65鎂合金具有較小的腐蝕電流密度(19.66 μA/cm²)和較高的陽極利用率(84.3%)，與未添加Ce的AP65鎂合金相比，陽極利用率提高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 is shifted from -1.648 V (vs SCE) 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 19.66 μA·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.

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