Anantharaman, M R; Sindhu, S; Bindu, Thampi R; Malini, K A; Philip, Kurian(Springer, April 19, 2002)
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Abstract:
The effect of frequency, composition and temperature on the a.c. electrical conductivity were
studied for the ceramic, Ni1–xZnxFe2O4, as well as the filler (Ni1–xZnxFe2O4) incorporated rubber ferrite
composites (RFCs). Ni1–xZnxFe2O4 (where x varies from 0 to 1 in steps of 0×2) were prepared by usual ceramic
techniques. They were then incorporated into a butyl rubber matrix according to a specific recipe. The a.c.
electrical conductivity (sa.c.) calculations were carried out by using the data available from dielectric
measurements and by employing a simple relationship. The a.c. conductivity values were found to be of the
order of 10–3 S/m. Analysis of the results shows that sa.c. increases with increase of frequency and the change is
same for both ceramic Ni1–xZnxFe2O4 and RFCs. sa.c. increases initially with the increase of zinc content and
then decreases with increase of zinc. Same behaviour is observed for RFCs too. The dependence of sa.c. on the
volume fraction of the magnetic filler was also studied and it was found that the a.c. conductivity of RFCs
increases with increase of volume fraction of the magnetic filler. Temperature dependence of conductivity was
studied for both ceramic and rubber ferrite composites. Conductivity shows a linear dependence with
temperature in the case of ceramic samples
Description:
Bull. Mater. Sci., Vol. 25, No. 7, December 2002, pp. 599–607
Anantharaman, M R; Solomon, M A; Joy, P A; Philip, Kurian(Taylor & Francis, August 16, 2010)
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Abstract:
Rubber ferrite composites (RFC) are magnetic polymer composites and have a
variety of applications as flexible magnets, pressure=photo sensors, and microwave
absorbers. The mouldability into complex shapes is one of the advantages of these
magnetic elastomers. They have the potential of replacing the conventional ceramic
materials, due to theire flexible nature. In the present study, the incorporation
of pre-characterized hexagonal ferrites, namely barium ferrite (BaFe12O19), into
natural rubber matrix is carried out according to a suitable recipe for various
loadings of the filler. The processability of these compounds was determined by
evaluating the cure characteristics: scorch time, cure time, and minimum and
maximum torque. It has been found that the addition of magnetic fillers does not
affect the processability of the composites, whereas the physical properties are
modified. The magnetic properties of these composites containing various loadings
of the magnetic filler were also investigated. The magnetic properties of RFC can
be controlled by the addition of appropriate amount of the ferrite filler.
Description:
International Journal of Polymeric Materials, 53:565–575, 2004
Anantharaman, M R; Malini, K A; Sindhu, S; Mohamed, E M; Date, S K; Kulkarni, S D; Joy, P A; Philip, Kurian(Springer, May 14, 2001)
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Abstract:
Rubber ferrite composites containing various mixed ferrites were prepared for different
compositions and various loadings. The magnetic and dielectric properties of the fillers as well as the ferrite
filled matrixes were evaluated separately. The results are correlated. Simple equations are proposed to
predetermine the magnetic and dielectric properties. The validity of these equations is verified and they are
found to be in good agreement. These equations are useful in tailoring the magnetic and dielectric properties of
these composites with predetermined properties
Description:
Bull. Mater. Sci., Vol. 24, No. 6, December 2001, pp. 623–631