熔盐电解共沉积Mg-Sr合金的电化学机理

来源期刊:中国有色金属学报(英文版)2014年第5期

论文作者:孙秀云 路贵民 范书迪

文章页码:1629 - 1634

关键词:熔盐电解;Mg-Sr合金;电化学还原

Key words:molten salt electrolysis; Mg-Sr alloy; electrochemical reduction

摘    要:采用循环伏安法、计时电位法和计时电流法,研究在700 °C时不同MgCl浓度下,MgCl2-SrCl2-KCl熔盐体系中Mg和Sr共沉积的电化学过程。结果表明:由于Sr在Mg上形成欠电位沉积而形成液态Mg-Sr合金,从而使得Sr的实际析出电位降低0.5 V左右。在阴极相对电位低于-1.5 V左右时,Mg会析出,当阴极相对电位低于-2.0 V时,Mg和Sr会共析出。在Mg和Sr共析出时,整个电极过程不再是简单的扩散控制。计时电位法研究表明,Mg和Sr产生共电沉积的条件是在MgCl2浓度分别为2%、5%和10%(质量分数)的熔盐中,阴极电流密度分别为超过0.71、1.57和2.83 A/cm2

Abstract: The electrochemical process of Mg-Sr codeposition was studied in MgCl2-SrCl2-KCl melts containing different MgCl2 concentrations at 700 °C by cyclic voltammetry, chronopotentiometry and chronoamperometry. The results show that the actual precipitation potential of Sr reduces by nearly 0.5 V because of the depolarization effects of Sr activity reduced by forming Mg-Sr alloy. The codeposition potential condition of Mg and Sr to form Mg-Sr alloy is as follows: When electrode potential is more negative than -1.5 V, the magnesium will precipitate; when elec trode potential is more negative than -2.0 V, the magnesium and strontium will both deposit. The con trol step of codeposition process of Mg and Sr is not diffusion control step. The codeposition cur rent condition of Mg and Sr to form Mg-Sr alloy by chronoptentiometry is as follows: cathode current densities are higher than 0.71, 1.57 and 2.83 A/cm2 in MgCl2-SrCl2-KCl melts with MgCl2 concentrations of 2%, 5% and 10% (mass fraction), respectively.

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