ISSN 10637397, Russian Microelectronics, 2011, Vol. 40, No. 7, pp. 463–468. © Pleiades Publishing, Ltd., 2011.
Original Russian Text © D.A. Usanov, A.V. Skripal’, A.V. Romanov, 2010, published in Izvestiya Vysshikh Uchebnykh Zavedenii. Elektronika, 2010, No. 5, pp. 28–35.
Adding various microinclusions for creating artifi
cial dielectrics allows deliberate changes to the the
electrophysical properties of composite materials.
These properties of the artificial insulators were stud
ied by the authors of [1, 2]. There are various ways to
create them, based on the introduction in a dielectric
medium, for instance, of paraffin  or polyethylene
, created by high pressure, and conducting inclu
sions, such as metal particles  or graphite . Fer
rite microparticles as additives for composite materials
are used to create absorbers, valves, and phase shifters.
The purpose of the study is to investigate the electro
physical properties of composites based on a poxy adhe
sive with inclusions in the form of carbon nanotubes,
particles of finedispersed graphite, and ferrite micro
particles in the frequency range from 0.1 up to 6 GHz.
In the study of composite materials with ferrite inclu
sions, we determined the influence of the vector orien
tation of the magnetic induction on the composite elec
trophysical properties during epoxy binder curing.
Composites based on epoxy adhesive with conduc
The tested samples were made of a
composite material, fabricated using doublecompo
nent epoxy adhesive (ED 20 plus polyethylenep
olyamine) as a matrix with a filler of a different volume
concentration. As a filler, we used carbon nanotubes,
microscopic particles of graphite, and M1000NM
grade ferrite powder (manganesezinc ferrite (Mn
Carbon nanotubes were made by means of chemi
cal vapor deposition of a propanebutane mixture on a
metal catalyst, with the following sizes: a diameter of
~20–30 nm, and length of ~1
m . Graphite pow
der was dispersed ultrasonically in ethanol for 1 h and
then dried in an oven at 120
C for 2 h. In order to
obtain a fine magnetic fraction, the ferrite powder was
subjected to grinding in a ball mill for 6 h and to sieving
through a sieve with a cell size of ~10
m. By using
particle size analysis technique , the average size of
the ferrite and graphite of 3.6
m and 8.5
m, respectively, were obtained. Filler was added
to the epoxy adhesive and thoroughly mixed until
smooth. We poured the mixture into cuvettes measur
1 mm and subjected to additional ultra
sonic treatment (frequency 44 kHz) for 40 min. Dur
ing the curing of composites with ferrite inclusions,
the cuvettes were placed between the poles of an elec
tromagnet with the magnetic induction
= 0.1 T, and
kept at ambient temperature for 6 h.
The samples containing carbon nanotubes and fine
graphite that were prepared by the above method have
a homogeneous structure.
The composite samples with ferrite inclusions,
which were formed in the process of curing in the mag
netic field with different orientations of induction vec
, had a structure that exhibited the different spa
tial arrangement of ferrite inclusions (ferrite fibers) in
the volume of the composite, which is schematically
shown in Fig. 1.
With the help of an optical microscope, we
obtained an image of a sample cut with ferrite inclu
sions (see Fig. 2). Here, the tested samples have a
structure characterized by the spatial arrangement of
ferrite inclusions in the composite volume in the form
of ferrite filaments of 12
m in diameter, spaced at a
m. The ferrite filaments are
directed along the magnetic induction vector.
Electrophysical Properties of Composites with Carbon Nanotubes,
Fine Graphite, and Feritte Microparticles as Inclusions
D. A. Usanov, A. V. Skripal’, and A. V. Romanov
Saratov State University, Saratov, Russia
—The electrophysical properties of composites based on epoxy adhesive with inclusions in the form
of carbon nanotubes, particles of finedispersed graphite, and ferrite microparticles have been investigated in
the frequency range from 0.1 up to 6 GHz. The effect of the spatial arrangement of ferrite inclusions in the
composite volume on the frequency of the transmission coefficient of microstrip photonic crystals has been
shown. Magnitudes of transmittance and reflection in the window of transparency of a photonic crystal has
been established to be determined by the spatial arrangement of the ordered ferrite inclusions (ferrite fila
ments) relative to the direction of an electric field vector of an electromagnetic wave and its direction of prop
agation the photonic crystal. It has been found that with an increase in the induction value of the orienting
magnetic field acting during an epoxy cure, the distance between the regularly arranged inclusions of ferrite
(ferrite filaments) decreases.