(1.中南大學(xué)材料科學(xué)與工程學(xué)院，長(zhǎng)沙 410083；
2.中南大學(xué)冶金與環(huán)境學(xué)院，長(zhǎng)沙 410083)
摘 要: 利用掃描電鏡(SEM)、X射線(xiàn)衍射(XRD)分析稀土元素La對(duì)Mg-Hg-Ga陽(yáng)極材料顯微組織的影響，并采用恒電流放電、動(dòng)電位極化掃描、交流阻抗法、陽(yáng)極效率測(cè)試和化學(xué)浸泡法研究La對(duì)Mg-Hg-Ga陽(yáng)極材料腐蝕電化學(xué)性能的影響。結(jié)果表明：La的添加能使Mg-Hg-Ga合金晶粒細(xì)化，大量的Mg17La2和LaHg6相聚集在晶界處呈網(wǎng)狀分布。隨著La含量的升高，合金電化學(xué)活性下降，耐腐蝕性能先降低后增加，陽(yáng)極效率先下降后升高，Mg-Hg-Ga-2%La合金的析氫速率為17.92 mL/(cm2？h)，陽(yáng)極效率為50.3%；而Mg-Hg-Ga-6%La合金的析氫速率僅為0.45 mL/(cm2？h)，陽(yáng)極效率為82.5%。這是因?yàn)殡S著La含量的升高，合金中新增的Mg17La2和LaHg6相為弱陰極性相，與α-Mg之間形成的腐蝕原電池驅(qū)動(dòng)力較小，從而抑制鎂基體的腐蝕。
關(guān)鍵字: Mg-Hg-Ga合金；顯微組織；電化學(xué)性能；陽(yáng)極效率
（1. School of Material Science and Engineering,Central South University,Changsha 410083,China;
2.School of Metallurgy and Environment,Central South University,Changsha 410083,China）
Abstract:The effect of La on the microstructure of Mg-Hg-Ga anodes was analyzed by scanning electronic microscopy(SEM) and X-ray diffractometry(XRD). The effect of La on electrochemical performance of Mg-Hg-Ga anodes was investigated by potentiodynamic polarization,galvanostatic test, electrochemical impedance spectroscopy,anodic efficiency test and chemical immersion method. The results show that the La addition can refine the grain of Mg-Hg-Ga alloy,large amounts of Mg17La2 and LaHg6 phases accumulate in grain boundary and distribute reticularly. The electrochemical activity of alloys declines with the increase of La content, while the corrosion resistance and anodic efficiency firstly reduce and then increase. The H2 evolution rate of Mg-Hg-Ga-2%La alloy is 17.92 mL/(cm2？h) and the anodic efficiency is 50.3%. While the H2 evolution rateof Mg-Hg-Ga-6%La is 0.45 mL/(cm2？h) and the anodic efficiency is 82.5%.The reason is that the newly formed Mg17La2 and LaHg6phasesare weakly cathodic phase with the increase of La content.The driving force of the corrosion cell forming between these phases andα-Mg is small,which will inhibit the corrosion of Mg matrix.
Key words: Mg-Hg-Ga alloy; microstructure; electrochemical performance; anodic efficiency
