3rd meeting of young researchers at UP 1 - IJUP - Universidade do ...

Environmental alternative for cadmium: nano structural alloys of
zinc and tin using ionic liquids.
S. Salomé 1 , A. F. Silva 1
1 Department of Chemistry, Faculty of Science, University of Porto, Portugal.
Electrodeposition of metals is essential for a variety of industries usually the process is carried
out from aqueous solutions [1]. Tin- zinc electrodeposits offer a good corrosion protection and
they have been deposited from a variety of aqueous baths including sulphate-tartrate [2],
gluconate [3] and pyrophosphate baths. These electrodeposits combine the barrier protection of
tin with the galvanic protection of zinc providing a ductile and corrosion resistant coating so, it
is not surprising that a number of applications of tin-zinc alloy deposits have been known and
well recognized [4].
Most recently the case of ionic liquids achieved the attention due to the possibility of
depositing metal which cannot be deposited from aqueous solution such as Al, Ti... Another
type of ionic liquids are those formed by mixing quaternary ammonium halides with suitable
hydrogen bond donner (HBD) which decrease the freezing point (DES) [5].
On this work assessed the possibility of deposits of Sn, Zn and Sn-Zn alloys from DES
prepared with choline chloride and different HBD: urea, ethylene glycol and 1,2-propylene
glycol. Results will be shown that illustrates the influence of the liquid on the thermodynamics
of electrodeposition using cyclic voltammetry performed with three electrode materials (Pt, GC
and steel). The kinetic of deposition was also study using chronoamperommetry. Fitting of the
data was carried out using known models of nucleation and growth as illustrated in Fig. 1.
x10 -3
25
20
15
10
5
0
0
20
372 3 rd meeting of young researchers at UP
40
x10 -3
60
80
-1.20 V
jdl
j3Diodz
jdl3Diodz
Fig. 1 Comparison of an experimental current density transient (—) recorded during Sn deposition on
glass carbon electrode and a theoretical transient (—) obtained by non-linear fit.
References:
[1] F. Endres, ChemPhysChem 3 (2002) 144.
[2] St. Vitkova, V. Ivanova and G. Raichevsky, Surf. Coat. Technol. 82 (1996) 226.
[3] E. Guaus and J. Torrent-Burgues, J. Electroanal. Chem. 575 (2005) 301.
[4] O.A. Ashiru and J. Shirokoff, Appl. Surf. Science 103 (1996) 159.
[5] A.P. Abbott, G. Capper, K. Mckenzie and K. Ryder, J. Electroanal. Chem. 599 (2007) 288.
100