Kinetics and Mechanism of the Magnesium Electrode Reaction in Molten MgCl2 ‐ NaCl Binary Mixtures
Kinetics and Mechanism of the Magnesium Electrode Reaction in Molten MgCl2 ‐ NaCl Binary Mixtures
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DOI：
10.1149/1.1837654
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发表时间：
1997-05
影响因子：
3.9
通讯作者：
A. Kisza;J. Kaźmierczak;B. Børresen;G. Haarberg;R. Tunold
中科院分区：
文献类型：
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作者：
A. Kisza;J. Kaźmierczak;B. Børresen;G. Haarberg;R. Tunold
用交流阻抗谱和恒电流微扰弛豫法测定了不同温度下镁电极在六种熔体中的反应动力学和反应机理。发现电极过程为三步法，高频段为纯电荷转移，低频段为混合电荷转移-扩散过程。高频阶跃的交换电流密度在20~50A cm-2之间，而低频阶跃的交换电流密度在3~10A cm-2之间。根据相应的交换电流密度以及结构和热力学数据，提出了这些熔体中整体电极反应的机理。低频交换电流密度随组成的变化过程与熔体中较低浓度的氯化镁溶液中氯化镁热力学活性的变化相对应。
Using electrochemical impedance spectroscopy and a relaxation method with galvanostatic perturbation the kinetics and mechanism of the magnesium electrode reaction in six melts of the binary MgCl 2 -NaCl system were determined at several temperatures. A three-step electrode process was found, the high frequency one being pure charge-transfer whereas the low frequency one showing mixed charge transfer-diffusion character. The exchange current density for the high frequency step is in the range from 20 to 50 A cm -2 whereas for the low frequency step it varies from 3 to 10 A cm -2 . On the basis of the corresponding exchange current densities and structural and thermodynamic data, a mechanism of the overall electrode reaction in these melts is proposed. The course of the low frequency exchange current density with the composition, corresponds to the change of the MgCl 2 thermodynamic activity in the more di ute solutions of MgCl 2 in the melt.