Russian Journal of Applied Chemistry, 2013, Vol. 86, No. 12, pp. 18421846.
Pleiades Publishing, Ltd., 2013.
Original Russian Text © V.V. Shtefan, A.Yu. Smirnova, 2013, published in Zhurnal Prikladnoi Khimii, 2013, Vol. 86, No. 12, pp. 18941898.
OF ELECTROCHEMICAL INDUSTRY
Electrochemical Formation of Cerium-containing
Oxide Coatings on Titanium
V. V. Shtefan and A. Yu. Smirnova
Kharkiv Polytechnic Institute, National Technical University, Kharkiv, Ukraine
Received December 10, 2013
Abstract—Possibility and conditions of obtaining cerium-containing oxide coatings on titanium alloys by microarc
oxidation in electrolytes with tartrate and citrate cerium complexes were determined. The effect of organic cerium
complexes on the kinetic parameters of the microarc oxidation of titanium alloys was studied. Porous oxides coat-
ings containing up to 20% cerium were obtained.
One of the most topical development ﬁ elds of
modern science is that associated with catalysis. Of
particular interest for preparation of catalyst supports
are processes in which thin ﬁ lms containing compounds
of rare-earth metals and, in particular, cerium oxides are
formed on valve metals.
Cerium-containing oxide systems are used in the
redox catalysis and catalytic oxidation of organic
contaminants as supports or a mixed support with
a transition-metal oxide, which provides unique
catalytic properties . Additions of cerium stabilize
the catalyst preclude its disintegration on being heated
and substantially enhance its activity and adsorption
properties and thereby provide a large degree of
decomposition of toxic substances.
One of methods widely employed to synthesize
oxide coatings on titanium is the microarc oxidation
(MAO), which consists in that oxide ﬁ lms are formed
on a metallic surface by electric breakdowns in aqueous
and nonaqueous electrolytes and yields multifunctional
ceramic-like coatings with high hardness and wear
resistance . The high-temperature reactions occurring
in electric discharge channels and adjacent zones can
form coatings containing both oxides of a metal being
processed and elements of electrolyte components .
The possibility of controlling the incorporation of the
electrolyte components into oxide layers of the substrate
metal enables synthesis of cerium-containing oxide
Not so many electrolytes for deposition of cerium-
containing coatings on titanium and its alloys by
microarc oxidation are presently known.
It was shown in  that surface cerium-containing
structures can be produced by MAO from aqueous
electrolytes with polyphosphate Ce
based on Ce(NO
. The amount
of cerium in the ﬁ lms depends on the molar ratio n =
] in the electrolyte.
The MAO method has been used to deposit oxide
ﬁ lms with a thickness of about 1.7 m and cerium
content of up to 3.4 at % on titanium from an aqueous
electrolyte containing 29.9 g L
It is known  that cerium forms soluble complexes
with tartrate and citrate ins. Electrolytes containing
tartrate ions are used for MOA of titanium to fabricate
electrically insulating and wear-resistant ﬁ lms providing
protection from corrosive media, high temperatures, and
mechanical and corrosion damage .
However, no data on the catalytic activity of these
coatings have been reported in these studies. In addition,
the electrolytes considered above demonstrate a small