(334f) The Crystal Orientation of Aluminium Coatings Deposited From Ionic Liquids

The
Crystal Orientation of Aluminium Coatings Deposited from Ionic Liquids

Yong Zheng, Jianmin Zhang, Xingmei Lu, Suojiang Zhang^*

Beijing Key Laboratory of Ionic Liquids Clean Process, State Key
Laboratory of Multiphase
Complex Systems, Institute
of Process Engineering, Chinese Academy of Sciences, 100190,
Beijing, P. R. China

^*Corresponding
author: sjzhang@home.ipe.ac.cn

Early in 1950s, Hurley et al. first found that
aluminium could be electrodeposited from the ionic liquid consisting of N-ethylpyridinium
chloride and AlCl₃ at low temperature. From then on, extensive and
systematical research on the electrodeposition of aluminium from chloroaluminate ionic liquids has
been reported in the literature [1,2]. However, more efficient ionic liquids should
be developed and investigated.

In this work, Lewis acidic 1-allyl-3-methylimidazolium
chloroaluminate ([Amim]Cl/AlCl₃) ionic liquids were used as
promising electrolytes in the low-temperature electrodeposition of aluminium. Compared
with the conventional ionic liquids, [Amim]Cl/AlCl₃
basedones have more favorable physicochemical properties. Smooth,
dense and well adherent aluminium coatings were electrodeposited from [Amim]Cl/AlCl₃
on the substrates at 10-25 mA/cm² and
313.15-373.15 K. It was
found that the crystallographic orientations of aluminium changed along with
the experimental conditions (see Figure 1). The results indicate that the
influence of experimental parameters on the crystal growth of aluminium
deposits follows the order, temperature > current density > molar ratio of
[Amim]Cl/AlCl₃. The
low temperature and high current density usually increase the peak intensity of
(200) plane, thus promote the crystal growth in this direction on the
substrates. Furthermore, the changes in crystal patterns can also influence the
surface morphology of deposits. According to the measurements of SEM and XRD,
the bright, smooth and well adherent deposits almost exhibit a preferred
orientation of (200).

Figure 1 XRD pattern of the aluminium coatings deposited from 1:2.0
[Amim]Cl/AlCl₃ at 20 mA/cm². The deposition temperature
(K): (a) 313.15, (b) 353.15, (c) 373.15.

References:

[1]  
Liu QX, Zein El Abedin S, Endres F. Surf Coat
Technol. 2006, 201: 1352-1356.

[2]  
Yue GK, Zhang SJ, Zhu YL, Lu XM, Li SC, Li ZX. AIChE
J. 2009, 55: 783-796.

Acknowledgements:

This
work was supported financially by the National Basic Research Program of China
(2009CB219901), National Key Technology Research and Development Program of the
Ministry of Science and Technology of China (2012BAF03B01), National Natural
Science Foundation of China (20906096) and Open-end Fund of State Key Laboratory of Multiphase Complex Systems (MPCS-2011-D-06).