CHARACTERIZATION OF ANTI-CORROSION TRIAZOLE FILM By ...

J.Sc. Tech ـــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ ــــــــــــــــــــــــــــــVol.
10(2) 2009
area at the lower part which was exposed to corrosive medium i.e. Red sea
water. The zinc electrode was polished with sand paper, washed in running
tap water, rinsed in distilled water before exposure to sea water and sea
water containing 0.01M MTRA inhibitor. The cyclic voltamograms were
obtained using an electrochemical system Autolab (Netherlands) at
corrosion potentials over a potential window between –2000 and 550 mV (vs
SCE) at sweeping rate of 10 mV/s. A three compartment cell with zinc as
working electrode, platinum foil and saturated calomel electrode as counter
and reference electrodes respectively were used for CV studies The scanning
electron micrographs of the polished zinc surface after exposure to sea
water and sea water containing 0.01M inhibitor were taken using vacuum
scanning electron microscope model JEOL JSM-5600 LV interfaced to a
computer and JSM software. The energy dispersive x-ray analysis (EDAX)
studies calibration was done with respect to Co Kα = 6.9254 keV and Co Lα
= 0.7763 keV.
RESULTS AND DISCUSSION
Organic compounds containing heteroatoms find application as
corrosion inhibitors as these atoms with lone pairs of electrons are a site of
their binding to metal surfaces [Leroy, 1978]. Triazoles derivatives are
becoming very important both as corrosion inhibitors for metals [Wang,
2001, Dermaj et al, 2007, El-sayed et al, 2007 and Taha, 2002] and as ligands
especially for complexation with transition metals [Raicheva et al, 1993].
The high inhibition efficiency for triazoles is attributed to their structures as
proved by ab initio quantum chemical calculations [Weihua et al, 2007]. The
correlation between the molecular modeling about the structure and
electronic effect and inhibition efficiency was studied by Bentiss et al
[2001].
Figures 1and 2 show the cyclic voltammetric response of zinc in the Red sea
water without and with the inhibitor. The results tabulated (Table 1) reveal
an anodic and a cathodic peak at 378 mV and – 1030 mV with currents 20.48
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