ISSN 1070-4272, Russian Journal of Applied Chemistry, 2016, Vol. 89, No. 9, pp. 1552−1555. © Pleiades Publishing, Ltd., 2016.
Original Russian Text © V.V. Rogozhin, E.Yu. Anan’eva, A.M. Abramov,
2016, published in Zhurnal Prikladnoi Khimii, 2016, Vol. 89, No. 9, pp. 1217−1221.
Side Effects in Electrolytic Deposition
of Nickel–Boron Coatings
V. V. Rogozhin*, E. Yu. Anan’eva, and A. M. Abramov
Alekseev State Technical University, ul. Minina 24, Nizhny Novgorod, 603950 Russia
Received September 27, 2016
Abstract—Some side effects arising in the course of electrolytic deposition of nickel–boron coatings in the pres-
ence of sodium decahydrodecaborate were revealed. Ways of using these effects in the practice of electrolytic
deposition of such coatings were demonstrated.
Nickel–boron coatings are widely used in the metal
electroplating practice as functional layers for various
branches of engineering . Such coatings are prepared
relatively readily by simple introduction of some
boron-containing additives into standard nickel plating
electrolytes . In so doing, nickel–boron coatings
with the controllable boron content from hundredth
fractions of percent to several percents are obtained,
with simultaneous changes in the structure and functional
properties of the coatings [3, 4].
The most effective boron-containing additives to
nickel plating electrolytes are polyhedral additives
, and some other
anions . Such additives are highly stable in storage
and operation, are simple in analysis and adjustment,
and exhibit low levels of electrochemical activity and
pH sensitivity. Sodium decahydrodecaborate (SDHB)
containing the В
anion is the most widely used
However, the use of such additives gives rise to
a number of side effects, both positive and negative,
inﬂ uencing the nickel–boron electroplating process itself.
Analysis of such effects is the subject of this study.
Electrolytic deposition of the coatings was performed
from the standard Watts nickel plating electrolyte .
To study changes in the concentration of the boron-
containing additive and in pH in the near-electrode
spaces, we used a W-shaped cell with the spaces separated
with diaphragms. The polarization and potentiometric
measurements were performed with an Elins-Р-30S
potentiostat. The pH was measured with a MARK 901 pH
meter. SDHB was analyzed by the standard iodometric
titration procedure. The SDHB concentration in most
cases was taken in excess (up to several g L
) for better
revealing its side effects. The electrolytes were prepared
by dissolving chemically or analytically pure grade
chemicals in calculated amounts of distilled water.
RESULTS AND DISCUSSION
The SDHB additive exhibits noticeable reducing
properties. This follows from the previously observed
negative shift of the currentless potential of the nickel–
boron electrode on introducing the boron-containing
additive into the standard Watts nickel plating electrolyte.
This potential shift increases in value with increasing
concentration of the additive, reaching –0.35 V at 3 g L
SDHB already at 25°C .
The reducing properties of sodium decahydrodecaborate
were conﬁ rmed by an electroless plating experiment,
when a small amount of the metal phase in the form of
nickel powder was detected on a freshly deposited Ni–B
sample at 95–98°С and deposition of the metal on the
vessel bottom and walls was also observed.