Influence of magnetic field-aided filler orientation on structure and transport properties of ferrite filled composites
| Autor: | Grzegorz Kmita, A. Wujek, Cz. Kapusta, Andrzej Rybak, Karolina Gaska, Kamil Goc, K. Klimczyk, Witold Prendota, Lukasz Jarosinski |
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| Rok vydání: | 2016 |
| Předmět: |
Materials science
Percolation threshold 02 engineering and technology Dielectric Epoxy 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Electronic Optical and Magnetic Materials Thermal conductivity visual_art 0103 physical sciences Heat transfer visual_art.visual_art_medium Ferrite (magnet) Composite material 010306 general physics 0210 nano-technology Anisotropy Curing (chemistry) |
| Zdroj: | Journal of Magnetism and Magnetic Materials. 419:345-353 |
| ISSN: | 0304-8853 |
| Popis: | Epoxy resins are materials commonly used for insulations and encapsulations due to their easy processing process and mechanical strength. For their applications in power industry and electronics the effective heat dissipation is essential, thus their thermal conductivity is one of the most important properties. Introduction of appropriate dielectric powders, preferably in an ordered way, can increase the thermal conductivity of the polymer while keeping its good electrical insulation properties. In this work we used strontium ferrite as a filler to study the evolution of the filler particles distribution in the fluid before curing. Magnetic ferrite particles were dispersed in liquid epoxy resin and formation of chain-like or more complex structures under applied external magnetic field was observed and investigated. Computer simulations made show that with increasing magnetic field these structures are characterized by longer chains, higher speed of particles displacement and stronger structural anisotropy. However, for highly-filled systems, stronger inter-particle interactions make the alignment process less effective. The effective thermal conductivity simulated with FEM methods increases with increasing filler content and the percolation threshold in aligned systems is achieved at lower filler concentrations than for reference isotropic samples. The results are compared with the experimental data and a good qualitative agreement is obtained. |
| Databáze: | OpenAIRE |
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