ISSN 1070-4272, Russian Journal of Applied Chemistry, 2014, Vol. 87, No. 4, pp. 439−443. © Pleiades Publishing, Ltd., 2014.
Original Russian Text © D.A. Vetrova, O.S. Kazakova, S.A. Kuznetsov, 2014, published in Zhurnal Prikladnoi Khimii, 2014, Vol. 87, No. 4, pp. 446−450.
AND CORROSION PROTECTION OF METALS
A Study of the Electrochemical Behavior of the Ti(IV)/Ti(III)
Redox Couple in the NaCl–KCl–NaF–K
in Order To Optimize the Electroreﬁ ning of Titanium
and Synthesis of Alloys Based on This Metal
D. A. Vetrova, O. S. Kazakova, and S. A. Kuznetsov
Tananaev Institute of Chemistry and Technology of Rare Elements and Mineral Raw Materials, Kola Scientiﬁ c Center,
Russian Academy of Sciences, Akademgorodok 26a, Apatity, Murmansk oblast, 184209 Russia
Received April 21, 2014
Abstract—Temperature dependence of the standard charge-transfer rate constant was obtained in a study of the
redox reaction Ti(IV) + e
Ti(III) in a (NaCl–KCl)
–NaF(10 wt %)–K
melt by cyclic voltammetry.
The processes of titanium reﬁ ning and high-temperature electrochemical syntheses of alloys on its basis can be
optimized by using this dependence.
Titanium alloys ﬁ nd wide use in modern technology
and, in particular, in powder metallurgy . One of practi-
cal problems encountered when obtaining titanium alloy
powders is in the high cost of their fabrication. Titanium
is obtained by magnesiothermic reduction of titanium
tetrachloride, and metals contained in a titanium alloy, by
metallothermic reduction of their oxides or chlorides .
Then the metals are mixed, melted at high temperatures in
the form of ingots, and the alloy is homogenized during
a long time at a certain temperature and converted to a
powder of required granulometric composition.
The multiple-stage nature of the process in which the
alloys are obtained, existence of wastes, and gross energy
expenditure make a search for other approaches a topical
issue. Recently, mechanical alloying has been success-
fully used to produce titanium alloys .
It is known that the properties of alloys largely depend
on their composition and homogeneity; at the same time,
it is difﬁ cult to obtain alloys with a constant component
ratio in manufacture of titanium compounds by the con-
ventional metallurgical methods, not to mention syntheses
of alloys of strictly stoichiometric composition.
This disadvantage can be overcome with electro-
chemical methods employed to form alloys with the use
of molten salts.
In [3–6], cobalt and vanadium were electrolytically
reﬁ ned and Ti–Co and Ti–V alloys were synthesized in
(20 wt %) melt. Using a K
containing electrolyte makes it possible to obtain cobalt
and vanadium alloys in situ by the reactions
2Ti(IV) + Co
2Ti(III) + Co(II), (1)
2Ti(IV) + V
2Ti(III) + V(II). (2)
Depending on the cathode current density, metallic
cobalt, vanadium, or titanium alloys can be obtained at the
cathode. Thus, the electrochemical method can produce
titanium alloys in a single stage at a substantially reduced
expenditure of energy and time.
To perform an electrochemical synthesis of titanium
alloys in molten salts, it is necessary to know the electro-
chemical behavior of titanium.
The electrode processes
were studied in [7–9] and the diffusion coefﬁ cients of
titanium complexes in various oxidation states were
determined. Data on the standard charge-transfer rate