离子液体中铝的电镀及其防护性能

Aluminum Electroplated from Ionic Liquids as Protective Coating against Steel Corrosion

采用66.7%(摩尔分数)AlCl_3与33.3%(摩尔分数)BMIC(1-丁基-3-甲基咪唑氯盐)混合后得到的AlCl_3-BMIC离子液体为电解液,在钢铁基体上采用恒电流法进行电镀铝的研究,主要考察了添加剂、温度、电流密度对镀层形貌的影响及镀层耐腐蚀性能。结果表明:温度45±2℃、甲苯含量为5～12ml/L、电流密度为20～25mA/cm^2时,能获得平整致密的铝镀层;所得铝镀层以(200)面构成为主,随电流密度的增加,(200)面峰增强;在电流密度25mA/cm^2电镀铝后,试样的腐蚀电位从-669mV(SCE)负移至-1019mV(SCE),腐蚀电流密度从65.7μA/cm^2变为6.07μA/cm^2,与纯铝的(E_(corr)=1031mV(SCE),I_(corr)=1.24μA/cm^2)相当。

An ionic liquid electrolyte was prepared by mixing 66.7 mol% anhydrous AlCl3 and 33.3 mol% 1-Butyl-3- methylimidazolium chloride （BMlC） in AlCl3 BMIC melt. The effect of temperature, current density, and amount of toluene additive on the electroplating process was studied. The characterization of the deposited aluminum was performed using scanning electron microscopy （SEM/EXD） and X-ray diffraction （XRD） techniques. The corrosion resistance of the deposited Al coatings was studied by electrochemical testing. The results showed that a dense and well adherent aluminum coating was obtained under the condilions of 45±2℃, current density of 20-25 mA/cm^2 , and content of toluene 5-12 ml/L. All of the electrodeposits exhibited a strong preferred （200） crystallographic orientation, and the preferred （200） orientation was enhanced with the increase of current density. By depositing Al coating at 25 mA/cm^2 , the corrosion potential Ecorr and the corrosion current density Icorr, of Fe substrate moved to negative direction from-669 mV （SCE） to -1019 mV （SCE）, from 65. 7μA/cm^2 to 6. 07μA/cm^2 separately, comparable to those of pure Al （Ecorr = - 1031 mV （SCE）, Icorr= 1.24 μA/cm^2 ）.