Improvement of thermal and electrical properties of Silicone–Ni composites using magnetic field

• Silicone rubber filled with several Ni filler concentrations were prepared.
• A magnetic field was applied to obtain three different spatial distributions of fillers.
• A higher heat transport ability was obtained for composites with parallel distribution fillers to the heat flux.
• A low electrical percolation threshold was obtained using with parallel distribution fillers.
• Thermal and electrical models were applied and compared with experimental data.

Thermally and electrically conductive silicone–rubber composites filled with nickel particles have been prepared for several filler concentrations and for three different spatial distributions using various magnetic field orientations. The alignment of metallic particles in the polymeric matrix was confirmed by SEM and optical observation of the microstructure of composites. The spatial distribution of the particles does not affect the specific heat behavior of composites; while higher heat and electric transport ability was reached for composites filled with alignment of particles along the main heat flux due to creation of 1D structure of Ni particles. This filler configuration allows enhancement of the thermal conductivity of about 100% compared to the transverse and random distribution of particles; and contributes also to reducing the percolation threshold from 25 to 2 vol.% of nickel particles. Thus a great improvement of both thermal and electrical behavior is obtained by using a magnetic field for the preparation of silicone–nickel composite.

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