Reserch Of Aluminum Electrodeposition Using AlCl₃-[EMIM] Ionic Liquid Under High Gravity Field

The different molar ratios of AlCl3-[EMIM] Br ionic liquids wereprepared under the protection of high-purity nitrogen at70℃, and theconductivities were measured. The conductivity rose as the temperatureincreased which accords with Arrhenius behavior, and the conductivitydecreased gradually with increasing of molar ratio AlCl3.Aluminum was successfully deposited in the molar ratio of2:1AlCl3-[EMIM]Br ionic liquids with the method of constant current andconstant potential at conventional gravity and super gravity field. Theinfluence of gravity coefficient, current density, potential, temperature, stirringspeed and deposits time on aluminum electrodeposition rate and currentefficiency was studied.At conventional gravity, the result shows that the electrodeposition raterises with the current density, temperature, stirring speed increasing atconstant current, the affect of deposition time is not obvious. At constantpotential, electrodeposition rate increase with the potential, temperature,stirring speed increasing, the higher temperature and larger voltage, the less electrodeposition efficiency.Under the super gravity filed, the electrodeposition rate rises with gravitycoefficient increasing, the electrodeposition efficiency increases and thendecreases. The electrodeposition rate electrodeposition efficiency of supergravity filed is higher than the same current density, temperature, anddeposition time at normal gravity. Analyze catholic surface morphology withScanning Electron Microscope (SEM), test the purity of cathode depositedaluminum with X-ray Energy Dispersive Spectroscopy (EDS). The resultsshowed that The electrodeposits obtained on electrodes were dense,continuous, well adherent, fine particle size at the conditions of current density20mA·cm-2, electrodeposition time60min and temperature40℃. Higherpurity of cathode deposited aluminum would be obtained at super gravity thannormal gravity. Cathode aluminum crystal structure was analyzed by X-raydiffraction (XRD) and refined crystal was gained in the super filed, thealuminum spectrum peak gradually close to the standard card (PDF).At constant potential, the electrodoposition rate and efficiency in thesuper filed is higher than conventional gravity. Catholic surface were analyzedby SEM and the result shows that the aluminum layer were dense, smooth,continuous at the conditions of voltage of4V, ttemperature40℃andelectrodeposition time60min. The purity and crystal of cathode aluminumwere analyzed by EDS and XRD, the result indicated that the more refinedcrystal were be obtained with the gravity coefficient increasing, the content of aluminum at cathode reach98.71%and (111) of Al has preferred orientation.