The role of 4-amino-5-phenyl-4H-1,2,4-triazole-3-thiol
in the inhibition of nickel–aluminum bronze alloy
corrosion: electrochemical and DFT studies
Ahmed Y. Musa
Anees A. Khadom
Abdul Amir H. Kadhum
Mohd Sobri Takriff
Abu Bakar Mohamad
Received: 17 March 2011 / Accepted: 16 May 2011 / Published online: 28 May 2011
Ó Springer Science+Business Media B.V. 2011
Abstract Inhibition of corrosion of nickel–aluminum bronze alloy (NAB) by use
of 4-amino-5-phenyl-4H-1,2,4-triazole-3-thiol (APTT) was investigated by moni-
toring weight loss and open-circuit potentials (OCP), and by use of electrochemical
impedance spectroscopy (EIS). Quantum chemical data were calculated by use of
the density functional theory (DFT) model. Results showed that APTT inhibits
corrosion of NAB alloy fairly well. The efﬁciency of inhibition increases with
increasing concentration of APTT, and adsorption of the inhibitor obeys the
Langmuir adsorption isotherm model. Negative values of adsorption free energy
indicate chemical adsorption is spontaneous. The theoretical study showed that
sulfur and nitrogen atoms (S, N7 and N8) were the reactive sites.
Keywords Alloy Á Weight loss Á EIS Á Acid corrosion Á Quantum chemical
Nickel–aluminum bronze (NAB) alloys with copper as the main element and also
containing 9–12% Al and 6% each of Fe and Ni are highly resistant to corrosion .
This type of alloy is used to manufacture components in direct contact with
corrosive media, for example pumps, valves, tubing, and heat exchangers [2, 3] The
corrosion of copper-based alloys and their inhibition by organic inhibitors in acid
solution have been studied by several authors [4–8].
Acidic solutions are used extensively in chemical and industrial processes, for
example acid pickling, acid cleaning, acid descaling, and oil wet cleaning [9, 10].
A. Y. Musa (&) Á A. A. Khadom Á A. A. H. Kadhum Á M. S. Takriff Á A. B. Mohamad
Department of Chemical and Process Engineering, Universiti Kebangsaan Malaysia, 43600 Bangi,
e-mail: firstname.lastname@example.org; email@example.com
Res Chem Intermed (2012) 38:91–103