不同加工状态AZ31镁合金电化学性能研究（英文）

Electrochemical Performance of AZ31 Magnesium Alloy under Different Processing Conditions

为选择一种高性价比的镁电池阳极材料,借助电化学工作站、光学显微镜(OM)、扫描电子显微镜(SEM)和X射线能谱分析(EDS)对不同加工状态的AZ31B镁合金电化学性能进行研究。分别将挤压、轧制、铸轧和铸态AZ31B镁合金作为阳极材料,测试其电化学性能。结果表明,在4种加工状态下,挤压态镁合金是性价比最高的一种阳极材料;其组织由均匀细小的晶粒和第二相组成,拥有最负的平衡电位,最低腐蚀电流密度和最小自腐蚀速率;挤压态样品腐蚀后,表面产生疏松细小,且均匀分布的腐蚀产物,降低了阳极极化,增加了阳极利用率。轧制和铸轧态的AZ31B镁合金的电化学活性和耐蚀性能相对挤压态的较低。铸态AZ31B镁合金由于较粗大的晶粒、第二相和铸造缺陷,表现出不稳定的放电曲线和较正的放电电位。不同状态AZ31镁合金的腐蚀均以点蚀为主。

In order to select a good cost-performance ratio magnesium alloy as anode material, the electrochemical properties of AZ31B magnesium alloy under different processing conditions were investigated by electrochemical workstation, optical microscope （OM）, scanning electron microscopy （SEM） and energy dispersed spectroscopy （EDS）. Extruded, rolled, cast-rolled and as-cast AZ31 magnesium alloys were prepared as the anode materials. The results show that under different processing conditions, the extruded al- loy is the best cost-performance ratio anode material among the four alloys. It possesses the most negative equilibrium potential, the lowest corrosion current density and the smallest free corrosion rate indicating the highest electrochemical activity due to the uniform fine grains and the second phase. Its corrosiun products are loose, dispersing uniformly on the extruded anode surface, prone to falling off which decrease the polarization and increase the utilization of the anode. The electrochemical activity and the corrosion resistance of the rolled and the cast-rolled alloys are relatively low, compared with the extrude samples. Due to the coarse grains, as-cast defects and coarse second phase distributed along the grain boundaries, the as-cast alloy has unstable discharge curve and positive discharge potential. The corrosions ofAZ31 magnesium alloy under different conditions are almost pitting corrosion.