ISSN 1070-4272, Russian Journal of Applied Chemistry, 2016, Vol. 89, No. 5, pp. 746í752. © Pleiades Publishing, Ltd., 2016.
Original Russian Text © A.R. Dubrovskii, M.A. Okunev, O.V. Makarova, E.A. Makhaev, S.A. Kuznetsov, 2016, published in Zhurnal Prikladnoi Khimii, 2016,
Vol. 89, No. 5, pp. 612í618.
Choice of the Substrate Material for Deposition
of a Superconducting Coating
A. R. Dubrovskii
, M. A. Okunev
, O. V. Makarova
E. A. Makhaev
, and S. A. Kuznetsov
Tananaev Institute of Chemistry and Technology of Rare Elements and Mineral Raw Materials, Kola Science Center,
Russian Academy of Sciences, Akademgorodok 26a, Apatity, 184209 Russia
Concern CSRI Elektropribor,
ul. Malaya Posadskaya 30, St. Petersburg, 197046 Russia
Received April 4, 2016
Abstract—The corrosion resistance of a series of materials (ceramic, beryllium, carbopyroceram) in a niobium-
containing melt of the composition NaCl–KCl–NaF (10 wt %)–K
(8 wt %) was studied. The electrolysis
parameters ensuring the deposition of uniform 40–50-ȝm-thick niobium coatings on spherical carbopyroceram
substrates were determined.
Operation of the overwhelming majority of
gyroscopes, including cryogenic gyroscopes, is based
on measuring the error angle of the frame relative to
the rotor tending to preserve unchanged its position in
the inertial space. The gyroscope accuracy is mainly
determined by the presence of perturbing moments of
various origins, leading to a change in the rotor position
relative to the inertial space, and by the accuracy of
The use of low temperatures and of the supercon-
ductivity phenomenon in making a gyroscope allows
the major fraction of perturbing moments to be reduced
and the accuracy of measuring the error angle to be
improved. As a result, the device accuracy will be im-
Niobium is used in cryogenic engineering for
already several decades. This is due to several factors.
Niobium is characterized by the largest area of
ideal diamagnetism and by high, compared to other
elements, critical temperature of the transition to the
superconducting state. Furthermore, niobium can
be readily processed by mechanical, chemical, and
Pure niobium is considered today as the material that
meets the requirements of high H
and low surface loss
to the greatest extent . Possible substrate materials for
the rotor are ceramic, beryllium, and carbopyroceram
The advantages of ceramic are preservation of me-
chanical properties at high temperatures and high wear
resistance. The drawbacks are relatively high density,
lack of conductivity and plasticity, high hardness, and
tendency to cracking.
Beryllium has low density, and its drawbacks are
anisotropy and high thermal expansion coefﬁ cient, ex-
ceeding that of niobium by a factor of almost 2.
Carbopyroceram is a carbon-based material with low
density; it is isotropic and conducting.
There are numerous methods for deposition of nio-
bium coatings. One of promising methods for deposi-
tion of superconducting niobium coatings is electrolysis
in molten salts, allowing deposition of uniform coatings
on items of complex shape. A molten salt is an aggres-
sive medium for niobium electroplating; therefore, it is
necessary to examine the behavior of substrate materials
in contact with the melt.