ISSN 1070-4272. Russian Journal of Applied Chemistry, 2006, Vol. 79, No. 3, pp. 386 !389. + Pleiades Publishing, Inc., 2006.
Original Russian Text + A.A. Bachaev, T.E. Kuzina, 2006, published in Zhurnal Prikladnoi Khimii, 2006, Vol. 79, No. 3, pp. 393!396.
AND CORROSION PROTECTION OF METALS
Features of Impregnation of Nickel Metal!Ceramic Porous
Supports for Electrodes of Alkaline Batteries
A. A. Bachaev and T. E. Kuzina
Nizhni Novgorod State Technical University, Nizhni Novgorod, Russia
Received November 10, 2005
Abstract-The features of nickel oxidation in impregnation of nickel metal!ceramic porous supports for
electrodes of alkaline batteries, which ensure their fabrication in a shorter time, were determined.
Nickel oxide electrodes (NOE) on a nickel metal3
ceramic (MC) porous support have high specific char-
acteristics and can be used in a wide range of current
densities and temperatures. At the same time, their
fabrication is a long power- and labor-consuming
process consisting of a number of successive stages
. The time and a large number of multicycle stages
in fabricating such electrodes are mainly caused by
the fact that impregnating porous MC supports in
a solution of nickel salts requires long time. The pores
of the electrode are filled with a solution of nickel
salts in the course of impregnation and then serve for
the formation of an active substance. Filling pores
takes 537% of the impregnation time . The duration
of the process is determined by the time necessary for
obtaining the active substance by electrochemical oxi-
dation of nickel from the support .
Reduction of the impregnation time in fabricating
MC NOE should diminish the power consumption
and increase the intensity of the process, which is
an urgent and practically important problem.
In this study we elucidated the features of nickel
oxidation under the impregnation conditions and
chose on their basis the routes for reducing the time
of fabricating MC NOE.
The parameters of nickel etching were determined
by analyzing two types of the electrochemical sys-
tems: Ni | Ni(NO
| Ni (I) and Pt | Ni(NO
| Ni (II)
. The polarization curves of the models studied
were obtained in the galvanostatic mode. The progress
of nickel oxidation was monitored by the values of the
electrode polarizations. In studying the models, we
used N0 nickel foil (nickel content 99.9%) and a 30 0
16 0 1-mm smooth platinum plate.
The phase composition of the oxidation products
was determined by the X-ray diffraction analysis as in
. The densities of the deposit formed on platinum
were calculated using the expression for the mass of
the unit cell. To do this, the unit cell volume was
identified with a crystal lattice constant estimated
graphically by the method described in .
To test the performance of the system Ni | solu-
tion | NiO
(x > 1), a NiO
(x > 1) film was pre-
liminarily deposited on platinum by the procedure
described in .
The electrodes were fabricated on 300 100 1.6-mm
MC nickel supports with a bulk porosity of 70375%.
Nickel(II) hydroxide in the pores of the MC supports
was obtained by the process described in [7, 8]. For
impregnation we used Ni(NO
We analyzed the polarization curves obtained in
system I (Fig. 1a) and used the results of the graphical
analysis to determine the parameters of the nickel
dissolution: the compromise nickel potential was
found to be 0.00 V and the current density of the dis-
solution, 13 0 10
. The results obtained
in calculating the polarizability of the cathodic and
anodic processes showed that nickel is oxidized with
a cathodic control. The degree of cathodic control
Thus, the oxidation rate of nickel in impregnation
of an MC support is determined by the hindrance of
the cathodic process. However, studying it on nickel
is rather complicated, because the Ni potential es-
tablished in the system studied is a compromise rather
than an equilibrium value. Therefore, it was suggested