ISSN 1070-4272, Russian Journal of Applied Chemistry, 2008, Vol. 81, No. 3, pp. 435!437. + Pleiades Publishing, Ltd., 2008.
Original Russian Text + L.E. Shpilevskaya, A.M. Safonova, 2008, published in Zhurnal Prikladnoi Khimii, 2008, Vol. 81, No. 3, pp. 449!452.
AND CORROSION PROTECTION OF METALS
Deposition of Electrically Conducting Polymeric Coatings
Using Copper-Plated Silica
L. E. Shpilevskaya and A. M. Safonova
Institute of General and Inorganic Chemistry, National Academy of Sciences of Belarus, Minsk, Belarus
Received June 18, 2007
Abstract-Silica was metallized by chemical copper plating, and the possibility of using this kind of silica as
an electrically conducting filler by itself and with addition of carbon or metal!carbon fibers for preparing
polymeric and paint-and-varnish electrically conducting coatings was studied.
Of particular interest with the development of tech-
nology (micro- and radio electronics) is a new type of
polymeric and paint-and-varnish coatings, electrically
conducting coatings. Preserving all the qualities of
polymeric coatings, namely, low density, high strength
and elasticity of films, good adhesion and anticorro-
sion properties, and a number of other valuable physi-
cochemical and mechanical parameters, electrically
conducting coatings, in addition, acquire one of the
most important properties of a metal, ability to con-
duct electric current. This enables their use instead of
metallic coatings in some cases.
The electrically conducting coatings are composite
coatings that contain conducting fillers in a polymeric
binder. As conducting fillers are used substances with
high conductivity: carbon black, graphite, technical-
grade carbon, carbon fibers, and powdered metals and
metal alloys. The choice of a component for preparing
electrically conducting coatings is governed by the set
of requirements to a coating as regards its electrical,
physical, chemical, and mechanical properties. The
electrical conductivity of composite coatings depends
on the type of a conducting filler (ability to conduct
electric current), size and shape of its particles,
filler concentration, chemical nature of the polymeric
binder, conditions of film formation, mode of its
curing and exploitation, and deposition technology .
The electrical conductivity is the highest for com-
posite coatings containing a metallic filler. However,
a disadvantage of such a filler is the high rate of its
sedimentation in the composite, which causes segrega-
tion of the material and leads to inhomogeneity of
the coatings obtained. In addition, a good conductivity
of coatings can be only achieved at a high metal
content (wt %) of the composite . This impairs
physicomechanical parameters of the coatings ob-
tained and makes higher their density.
At present, the so-called core-pigments, combined
particles with a metal-plated surface, find steadily
increasing use as fillers [3, 4]. Core-pigments make it
possible to diminish the density of a conducting poly-
meric coating and its cost, without making lower its
electrical conductivity. Of particular interest are core-
pigments produced by metallization of inorganic
materials and, in particular, mica, glass spheres, and
silica. Polymeric composites containing pigments of
this kind show high spreading capacity and slower
filler settling, and coatings produced on their basis
have low electrical resistance and good heat-insulating
properties . In addition, metallized silica particles
can be used as a starting stock for the subsequent
sintering of ceramics, by analogy with the processes
described in .
The electroless method for deposition of metallic
coatings onto nonmetallic surfaces is well understood
[7, 8], and, therefore, its application to metal plating
of various insulators poses no difficulties. However,
the deposition conditions should be adjusted to each
particular kind of a substrate.
The aim of this study was to obtain copper-plated
silica and analyze the possibility of its use as an elec-
trically conducting filler in deposition of polymeric
and paint-and-varnish coatings.
Sieved silica of the OVS-15 brand from the Novo-
selkovskoe deposit (Ukraine) was used in the study.