【作者】 汤燕；

【导师】 谢卫东；

【作者基本信息】 重庆大学 ， 材料学， 2010， 硕士

【摘要】 镁合金是在实际应用中最轻的金属结构材料,具有较高的比强度、比刚度,良好的阻尼性、切削加工性及导热性,极强的电磁屏蔽能力以及易回收等特点,被广泛的应用于航空航气、军用品、交通工具等领域,特别是在车辆产业和3C产品中发展尤为迅速。电化学还原法是制备原镁的两大方法之一。本论文提出一种多金属同步电化学还原直接制备镁合金的新思路。采用熔盐电化学还原理论,计算并分析了理论分解电压和金属的的电极电位。设计了两种实现金属同步电化学还原直接制备镁合金的途径:熔盐法和氧化物法;设计、制作了电化学还原实验装置,并在其上进行了熔盐法多金属同步电化学还原制备镁合金的实验研究。采用光学显微镜(OM)、扫描电子显微镜(SEM)、X射线衍射分析仪(XRD)等检测工具对制备的Mg-Al-Sr-Ca合金试样进行了表征;设计了氧化物法制备镁合金工艺,分析了其理论可行性。研究结果表明:第一,CaCl2具有较强的容氧能力、导电性好、环境影响小、资源丰富、价格低廉等特性,是电化学还原制备镁合金的较为理想的电解质。第二,在镁-铝合金熔体中电解SrCl2-CaCl2混合熔盐,能够制备出镁-铝-锶-钙合金。SrCl2与CaCl2物质的量为1:1的混合熔盐具有良好的可电解性能,其适宜的电解温度为750℃,电解电压为4V。第三,熔盐法多金属同步电化学还原制备的Mg-6Al-0.2Al-0.2Ca合金中,锶和钙主要以Al4Sr、Al2Ca的形式存在于基体晶粒晶界处。第四,将MgO、成分金属氧化物、粘结剂及助剂等混合制成固态阴极,浸在CaCl2熔盐中进行电化学还原,能实现MgO、成分金属氧化物等的同步电化学还原。更多还原

【Abstract】 Mg alloy are the lightest structural materials with many advantages such as high specific strength,specific stiffness,damping capacity,machinability,heatconducting good magnetic screen and easier to reycle etc. alloys are the lightest structural materials with many advantages such as high specific strength,specific stiffness,damping capacity,machinability,heatconducting good magnetic screen and easier to recycle etc.Mg alloys are widely used in several industrial fields,such as aerospace,weapon,automotiveetc.The application of Mg alloys in automobile and 3C products develops quickly.Electrochemical reduction is one of the two techniques of preparation of magnesium.A new idea to prepare Mg alloy by synchronous polymetallic electrochemical reduction was proposed in the thesis. In this paper,according the theory of molten salt electrolysis,the decomposition voltage molten salt and the electrode potential of the metals were calculated and analysised. The two routes including molten salt method and oxide process can achieve the target.Then the electrochemical reduction experimental device was designed,and on it a series of experimental studies of Mg alloys electrochemical reduction was finished.And optical microscopy(OM),scanning electron microscopy(SEM),X-ray diffraction(XRD),and other inspect means were used to analyse the experimental results.The preparation of electrochemical reduction of oxide solid-state electrode was designed. The results show that:O2-ion can stay in CaCl2 largely, and the current intensity of CaCl2 was good.Then it was cheap, considered as an ideal electrolyte of this process.In the magnesium-aluminum alloy melte,SrCl2-CaCl2 molten salt mixture was electrolyzed to prepare Mg-Al-Sr-Ca alloy.The feasible voltage of the mixture was 4.0V,and the fitting temperature was 750℃.Sr,Ca alloying elements gathered in the dendrite/boundary of the primary phaseα-Mg in the prepared Mg-6Al-0.2Sr-0.2Ca alloy.The solid-state cathode including MgO/other oxides can be electrolysed in CaCl2?fused salt .It can make thesynchronous polymetallic electrochemical reduction of MgO/other oxides ture.更多还原