【作者】 周丹桂；

【导师】 华一新；

【作者基本信息】 昆明理工大学 ， 冶金物理化学， 2009， 硕士

【摘要】 由特定的阳离子和阴离子组成的离子液体,在室温或近于室温下呈液态的离子化合物,电化学窗口很宽,可用于金属的电沉积。本文合成了氯化1-丁基-3-甲基咪唑([bmim]C1中间体和[bmim]BF4、[bmim]PF6、[bmim]Cl-AlCl3离子液体。在不同温度、有氧和无氧的条件下研究金属在离子液体中的溶解。测定了有氧和无氧的外在条件下,金属(Al、Cu、Fe)在离子液体中的溶解性能。实验结果表明,实验温度越高,金属的溶解速率越快,失重越多,金属离子在离子液体中的饱和浓度越大。空气的介入对金属在离子液体中溶解的影响很大,能改变金属的溶解机理。Al在[bmim]BF4和[bmim]PF6离子液体中几乎不溶,Al2O3膜阻隔了Al与离子液体的接触。一旦破坏了Al2O3保护层,Al的溶解速率加快。在[bmim]Cl-AlCl3离子液体中Al被Cl-腐蚀,溶解的很快。三种离子液体都能溶解金属Fe,但在[bmim]Cl-AlCl3离子液体中的溶解量最大,溶解速率基本恒定,不同条件下反应的活化能有很大差异。Cu在[bmim]PF6中的溶解很少,但在[bmim]Cl-AlCl3离子液体中被剧烈腐蚀。必须有氧存在Cu才能在[bmim]BF4离子液体中溶解。在25至70℃、空气气氛下,Cu溶解的表观活化能为21760 J/mol金属Cu、Fe、Al在离子液体中的溶解性有差异。[bmim]BF4离子液体对金属Cu、Fe、Al的溶解顺序为Cu>Fe>Al。[bmim]PF6离子液体对金属Cu、Fe、Al的溶解顺序大致上为Fe>Al>Cu。在[bmim]BF4离子液体中,Cu2+的饱和浓度随氧分压增大而增大。相比[bmim]BF4和[bmim]PF6离子液体,因为有Cl-的存在,Cu2+在[bmim]Cl-AlCl3中的饱和浓度最大。Cu在[bmim]BF4离子液体中的溶解过程受扩散控制,反应速率主要取决于生成的Cu2+从固液界面扩散到溶液主体中的速率。在不同氧分压和温度下Cu在[bmim]BF4离子液体中的反应速率方程为随着温度的升高,Cu的腐蚀电位逐渐负移,腐蚀电流密度不断增大,腐蚀速率也随之加快。氧气气氛下,Cu的腐蚀电位、腐蚀电流密度和腐蚀速率最大,电位随着氧分压的减小逐渐负移,速率随氧分压的减小逐渐减小。相对于空气和氩气,氧气气氛下离子液体[bmim]BF4溶液电位最高。增大氧分压能加强溶液的氧化还原能力,即提高溶液电位。溶液电位的升高能加速金属的溶解。更多还原

【Abstract】 Ionic liquids which are completely composed of anions and cations, are liquids at ambient temperature. Many metals can be eletrodeposited from ionic liquids because they have wide electrochemical windows.In this paper, 1-buty-3-methylimidazolium chloride ([bmim]Cl) intermediate、[bmim]BF4、[bmim]PF6 and [bmim]Cl-AlCl3 ionic liquid were prepared. Dissolution of metals in ionic liquids with or without the oxygen and under different temperatures was investigated.Dissolution of metals (Al、Cu、Fe) in ionic liquids under the conditions of hermetic and oxygen involved were measured. The experimental results showed that the dissolution rate of metals and saturation concentrations of metal ions in ionic liquids increased with increase in the temperature. Air involved appears to play a significant role in dissolution of metals in ionic liquids, which can change the dissolution mechanism.Al can hardly be dissolved in [bmim]BF4 and [bmim]PF6. Al and the ionic liquids were obstructed by the Al2O3 film. If Al2O3 layer was destroyed, Al can dissolve soon. Whereas Al in [bmim]Cl-AlCl3 was corroded by Cl-.Fe can be dissolved in three kinds of ionic liquids. Moreover, the dissolution magnitude of Fe in [bmim]Cl-AlCl3 was the largest, and the dissolution rate was basically constant. The apparent activation energy varied greatly under different conditions.The dissolution magnitude of Cu in [bmim]PF6 was little. But Cu in [bmim]Cl-AlCl3 was corroded significantly. Cu can only be dissolved in BMIMBF4 in the present of oxygen. According to the experimental data, the value of apparent activation energy was found to be 21760 J/mol in the temperature range from 25 to 70℃under the air atmosphere.The dissolution of Cu、Fe、Al in ionic liquids were different. The dissolution order of Cu、Fe、Al in [bmim]BF4 is expressed as follows Cu>Fe>AlSimilarly, the dissolution order of Cu、Fe、Al in [bmim]PF6 is expressed as follows Fe>Al>CuThe saturation concentrations of Cu2+ in [bmim]BF4 increased with increase in the oxygen partial pressure. Compared with [bmim]BF4 and [bmim]PF6, the saturation concentrations of Cu2+ in [bmim]Cl-AlCl3 was the largest due to the present of Cl-.Dissolution of Cu in BMIMBF4 is a diffusion-controlled process, the rate of that mainly depends on the diffusion of Cu2+ from the solid-liquid interface to the bulk solution. The rate equation of Cu dissolution in BMIMBF4 under different oxygen partial pressures and temperatures can be expressed asThe corrosion potential of Cu in [bmim]BF4 shifts negatively with increase in the temperature, and the current density and corrosion rate increased with increase in the temperature. The corrosion potential、current density and corrosion rate were maximal under the oxygen atmosphere. The corrosion potential shifts negatively with decrease in oxygen partial pressure, and the corrosion rate decreased gradually with decrease in oxygen partial pressure.The [bmim]BF4 potential is maximal under the oxygen atmosphere comparing with air and argon, and which increased with increase in oxygen partial pressure. The dissolution rate of metals can be accelerated with the [bmim]BF4 potential improved.更多还原