Morphology Study of Aluminium Deposition from Room Temperature Ionic Liquids (RTIL)

number: 
3575
English
department: 
Degree: 
Author: 
Noor Laith Dawood
Supervisor: 
Dr. Hadi M. A. Abood(Assist. Prof.)
year: 
2016

   Aluminium metal processing is only feasible at high temperature like extraction by electrochemical process from its ores at high temperature.Such process are not feasible in aqueous liquids due to production of hydrogen (-0.8V) much prior to aluminium electroreduction (-1.65V).Other solvents such as organic and ionic liquids have their setbacks for many practical, economic and environmental reasons. Protective coating of metals by aluminium thin layer is an important for preventing substrate metals from corrosion or for decorative purposes.Electrodeposition of aluminium on copper substrate from aluminium chloride / urea ionic liquid (AlCl :Urea) as electrolyte was successfully conducted at variable conditions. Protected by a layer of Decane on the top of the liquid under statistic air. The deposit microstructure was monitored by changing temperature, mole ratio, potential and deposition time. The surface morphology of deposited aluminium was investigated by visual microscope, Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and Energy Dispersive X-ray analysis (EDAX). 3 The effect of changing parameters on the morphology and microstructure of deposited aluminium was systematically studied.Results showed that by increasing temperature, the current density was increased linearly as a function of temperature and the visual appearance of deposited aluminium was changed with increasing emperature  from silvery white at 200 C to darker gray at 600C. The deposit microstructure was changed with increasing temperature and  the percentage of deposited aluminium increased with increasing temperature (20  to 50)0C from 55 At. % to 91 At. %, while at 60C thepercentage of deposited aluminium dropped from 91 At.% at 50C to 82At. % at 60 0C.Mole ratio of ionic liquid was also found to effect the deposit microstructure and the percentage of deposited aluminium which increased with increasing concentration of AlClin electrolyte. In the same manner, current density was increased with increasing mole ratio.3 Increasing deposition time with fixed potential and mole ratio of ionic liquid have only increasing the percentage of deposited aluminium.Using different electrodeposition potential at same mole ratio of ionic liquid  resulted in changing the morphology and deposited microstructure aluminium coatings with an increase in  current density with increasing cell potential.