1070-4272/01/7411-1958$25.00C2001 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 74, No. 11, 2001, pp. 1958!1959. Translated from Zhurnal Prikladnoi Khimii, Vol. 74, No. 11,
2001, pp. 1895!1897.
Original Russian Text Copyright + 2001 by Kabanov, Perelygin.
Electrodeposition of Palladium!Zinc Alloy
from the Ammonium Chloride!Na
S. V. Kabanov and Yu. P. Perelygin
Penza State University, Penza, Russia
Received April 26, 2001
Abstract-The influence of the electrolysis regime and electrolyte composition on the cathodic current
efficiency by the palladium3zinc alloy and on the alloy composition was studied.
Coatings with alloys of palladium and a number of
metals have found application owing to lower con-
sumption of noble metal and enhanced physicomech-
anical and chemical properties . A metallurgical
palladium3zinc alloy is a complex system consisting
of a solid solution at a zinc content of up to 6% and
of a few chemical compounds at higher zinc contents
. In this work wee examined electrodeposition
of the palladium3zinc alloy, which was not studied
Electrodeposition was performed from the am-
EDTA solution in a 100-ml
glassy rectangular bath using permanent graphite
anodes. Zinc in the alloy was determined by com-
plexometric titration after separating palladium in
the form of palladium dimethylglyoximate .
The influence of the electrolysis conditions and
electrolyte composition on the cathodic current effici-
ency (CE) by the alloy and the alloy composition
were studied in a solution containing (g l
chloride 20 (in terms of metal), zinc oxide 5 (in terms
of metal), ammonium chloride 20, and Na
40. The temperature was 20oC, current density,
0.5 A dm
, and pH 9.
As the zinc concentration in the electrolyte is in-
creased, its content in the coating increases and the
CE by the alloy decreases.
Zn concentration in 2345
solution, g l
Zn content of the alloy, % 2.7 4.1 5.5 7.8
Cathodic CE by the alloy, % 98 98 98 96
The dependence of the relative content of the alloy
metals on the relative concentration of their ions in
the electrolyte is described by the equation 
logÄÄÄ = 0.4 + 1.16logÄÄÄÄÄ.
The correlation coefficient of the equation is 0.993.
At the zinc concentration in the electrolyte in-
creased to 10 g l
, the CE by the alloy decreases
from 96 to 33% and the zinc content in the alloy in-
creases from 7.8 to 31%. Decreasing palladium con-
centration in the electrolyte under the similar condi-
tions results in the deterioration of the deposit quality.
The influence of the current density, temperature,
and pH was studied in an electrolyte with a zinc con-
centration of 5 g l
. At the current density increased
from 0.25 to 1.25 A dm
, the CE by the alloy de-
creases from 96 to 83% and the zinc content in the
alloy, from 18 to 4.5% (Fig. 1, curves 1 and 2, respec-
tively). At higher current densities the coating quality
gets worse. As the temperature is increased from 10
to 40oC, the CE by the alloy grows from 74 to 98%
Fig. 1. (1, 3) Current efficiency CE by the alloy and
(2) zinc content of the alloy C
vs. (1, 2) cathodic current
and (3) temperature T.