Russian Journal of Applied Chemistry, 2014, Vol. 87, No. 1, pp. 5460.
Pleiades Publishing, Ltd., 2014.
Original Russian Text T.I. Devyatkina, E.I. Yarovaya, V.V. Rogozhin, T.V. Markova, M.G. Mikhalenko, 2014, published in Zhurnal Prikladnoi Khimii,
2014, Vol. 87, No. 1, pp. 5865.
OF ELECTROCHEMICAL INDUSTRY
Anodic Oxidation of Complex Shaped Items of Aluminum
and Aluminum Alloys with Subsequent Electrodeposition
of Copper Coatings
T. I. Devyatkina, E. I. Yarovaya, V. V. Rogozhin, T. V. Markova, and M. G. Mikhalenko
Nizhni Novgorod State Technical University, ul. Minina 24, Nizhni Novgorod, 603950 Russia
Received December 10, 2013
Abstract—It was shown that the method of anodization of aluminum and aluminum alloys can be applied for sub-
sequent plating of highly adherent copper coating instead of the known zincate treatment with additional annealing.
Fluorine-containing additives in anodizing electrolyte were proposed as activator of oxide ﬁ lm. The parameters of
the anodic ﬁ lm (thickness, porosity, and microroughness) were calculated. The plated quality copper coatings have
high adhesion to the aluminum support, and no additional heat treatment is required. This considerably reduces
the processing time for deposition of multilayer coatings and decreases the material costs.
Aluminum alloys are the main construction material
in aircraft, automotive industry, and electrical engineer-
ing. Their application in other industrial areas may be
expanded by applying different galvanic coatings, which
increase the resistance to corrosion and mechanical wear,
enhance surface electrical conductivity, improve solder-
ability, and exhibit decorative properties .
At the same time, electroplating onto aluminum al-
loys involves a number of speciﬁ c difﬁ culties. These are
the presence of natural oxide ﬁ lm on the surface, which
impedes strong adhesion between the substrate and the
coating, and a large electronegative value of the electrode
potential of aluminum. Therefore, the special methods,
such as zincate treatment, chemical oxidation, and an-
odization, are used for surface preparation of aluminum
articles prior to plating.
The zincate treatment, commonly used in practice,
requires additional heat treatment and does not ensure
high adherence. In this case, electroplated coatings should
only be used in light and moderate conditions .
The chemical oxidation, a cheap and simple method of
the aluminum treatment, is commonly used for preparing
a support under paint coatings. The ﬁ lms obtained by the
chemical oxidation are signiﬁ cantly inferior in mechani-
cal and protective properties to the oxide ﬁ lms obtained
by the electrochemical method. Therefore, the chemical
oxidation of aluminum has limited application .
Compared to other methods, preliminary anodiza-
tion in acid solutions enables a more strong adhesion of
galvanic coatings to the aluminum support. Adhesion of
the oxide ﬁ lm to aluminum is very high. Owing to its
porous structure, the ﬁ lm, 2–4 m thick, is a good hold-
back agent for dyes and serves as a reliable sub-layer for
deposition of galvanic coatings. For example, the desired
adhesion of the electroplated coatings can be achieved in
anodic oxidation in a (15–55%) phosphoric acid. How-
ever, a signiﬁ cant disadvantage of this process is its high
sensitivity to minor changes in the alloy composition. In
this respect, a solution containing a mixture of sulfuric
and phosphoric acids (15 vol % H
+ 15 vol % H
is the universal electrolyte for anodizing aluminum and
its alloys .
Onto the obtained oxide ﬁ lm, a copper coating should
be applied from the pyrophosphate electrolyte . How-
ever, for this electrolyte the working current density and
the cathodic current efﬁ ciency are low. Also, pH of the