Russian Journal of Applied Chemistry, 2012, Vol. 85, No. 11, pp. 1691−1694.
Pleiades Publishing, Ltd., 2012.
Original Russian Text © Z.R. Obidov, I.N. Ganiev, 2012, published in Zhurnal Prikladnoi Khimii, 2012, Vol. 85, No. 11, pp. 1781−1784.
TECHNOLOGY OF ELECTROCHEMICAL
AND OTHER INDUSTRIES
Anodic Behavior and Oxidation of the Thallium
Alloyed Al + 2.18% Fe Alloy
Z. R. Obidov and I. N. Ganiev
Nikitin Institute of Chemistry, Academy of Sciences of the Republic of Tajikistan, Dushanbe, Tajikistan
Received March 20, 2012
Abstract—A study of the corrosion-electrochemical and thermal properties of the thallium-alloyed Al + 2.18% Fe
alloy demonstrated that the corrosion potential of the alloy can be raised and the heat conductivity be improved.
It is known that aluminum holds the second place
after steel in the amount of its use in various ﬁ elds of
technology. Aluminum and its alloys are particularly
valuable in that, being equally strong, they have nearly
three times lower weight than steel and possess high
anticorrosion resistance . However, raw aluminum
extracted from electrolyzers contains a number of
metallic impurities , including iron and silicon
passing directly from raw materials. The poor purity of
aluminum is also one of the main reasons for the pitting
Based on the constitution diagram of the Al–Fe
system, we chose an aluminum alloy with 2.18 wt %
iron, which is eutectic. Corrosion-resistant aluminum–
iron alloys can be developed, and their properties be
improved, by introduction of special additives, alloying
elements. We chose metallic thallium as an alloying
element for the given alloy.
The goal of our study was to examine the effect of
thallium additives on the corrosion-electrochemical
behavior and physicochemical properties of the Al +
2.18% Fe alloy.
As object of study served A7 aluminum, iron of
analytically pure grade, and T100 thallium. We prepared
alloys from these metals in an aluminum oxide crucible
in a SShOL shaft resistance furnace in the temperature
range 900–1100°C. The alloys were used to cast rods
8 mm in diameter and 140 mm long into a graphite
mold. The inoperative surface of the samples was
insulated with a resin composed of a mixture of rosin
and parafﬁ n taken in a 50 : 50 ratio. The corrosion-
electrochemical behavior of the thallium-alloyed Al +
2.18% alloy was studied in 0.03, 0.3, and 3% NaCl
solutions by the method described in . A schematic
of how a polarization curve of the Al + 2.18% Fe alloy
alloyed with 0.01 wt % thallium was measured is shown
in Fig. 1. The potential sweep rate was 2 mV s
a silver chloride electrode as reference, and platinum
as auxiliary electrode. The corrosion rate K, which is
a function of the corrosion current density icor, was
calculated by the formula
K = i
where æ is the electrochemical equivalent whose
numerical value for aluminum is 0.335 g A
The chemical composition and the results of our
study of the corrosion-electrochemical properties of the
Al–Fe–Tl system are listed in Table 1 and presented in
Figs. 2 and 3.
The variation of the corrosion potential of the
thallium-alloyed Al + 2.18% Fe alloy with time in a 3%
NaCl solution was recorded during 1 h (Table 1, Fig. 2).