Russian Journal of Applied Chemistry, 2012, Vol. 85, No. 2, pp. 229−232.
Pleiades Publishing, Ltd., 2012.
Original Russian Text © T.N. Pilipenko, V.G. Eﬁ mova, 2012, published in Zhurnal Prikladnoi Khimii, 2012, Vol. 85, No. 2, pp. 240−243.
AND CORROSION PROTECTION OF METALS
A Study of the Effect of Metal Corrosion Inhibitors
on the Hydrogenation of Steel and Changes
in Its Plasticity upon Etching in Sulfuric Acid Solutions
T. N. Pilipenko and V. G. Eﬁ mova
“Kiev Polytechnic Institute,” National Technical University, Kiev, Ukraine
Received July 7, 2011
Abstract—Effect of metal corrosion inhibitors, N-acetylmethylpyridium salts, on the hydrogen charging of 08
KP steel and changes in its plasticity upon its etching in solutions of 3 M sulfuric acid. Inhibitors more strongly
diminishing the fraction of hydrogen atoms diffusing into the steel and preserving or raising its plasticity as
compared with the shipment level were found.
It is known [1, 2] that one of the main factors that
impair mechanical characteristics of steels brought
in contact with acid solutions is their hydrogenation.
Another possible reason for loss of strength by the metal
is nonuniform corrosive disintegration of its surface
layers, accompanied by formation of stress concentrators
and local corrosion seats.
In most cases, introduction of inhibitors into corrosive
media improves mechanical properties of steels because
of the decrease in their content of hydrogen. However,
protective mechanisms of the presently used corrosion
inhibitors have been insufﬁ ciently studied: none of
these can exhaustively account for numerous cases of
inhibition of hydrogen charging and for the effect of
inhibitors on mechanical characteristics of metals. It is
also known [1–3] that most of corrosion inhibitors that
hinder dissolution of the metal not only fail to protect
it from hydrogen charging, but even may lead to more
pronounced penetration of hydrogen into the metal.
This circumstance largely restricts applicability areas of
many inhibitors exhibiting a strong protecting effect in
acid corrosion and requires development of other, more
efﬁ cient inhibitors that would not only hinder dissolution
of the metal, but also improve its mechanical properties,
such as strength and plasticity. The latter is particularly
important in inhibition of the acid corrosion of strained
or etched metals further subjected to mechanical loads.
In this study, we examined the effect of metal cor-
rosion inhibitors, N-acetylmethylpyridium salts, on the
hydrogen charging of steel and changes in its plasticity
upon etching in inhibited sulfuric acid solutions.
Tests were performed at 20°C by intertwining
of etched wire samples of 08 KP steel 7.5 × 10
diameter and 0.12 m long on a K-5 installation  at
a plastic deformation applied at a rate corresponding to
the rotation speed of 30 rpm and a load of 12 N. Seven
wire samples were used for each test in the background
and inhibited 3 M H
The protecting effect of corrosion inhibitors at
a concentration of 1 × 10
M in sulfuric acid solutions
was evaluated by the steel plasticity loss suppression
coefﬁ cient γ
and relative loss of plasticity, Δδ (%),
calculated by the equations
Δδ = [(Q
] × 100, (2)