Magnetic properties of soft magnetic composites
The influence of the amount of soft magnetic particles and their specific properties on the total soft magnetic properties of polymer based composites have been studied.
The filler fraction depending loss dissipation raises by lowering the content of soft magnetic particles in the polymer. For filler fractions x ≤ 0.5 and a frequency f ≥ 50Hz an incline of anomalous losses could be observed, evoked by a lowered effective number of active domain walls. It has also been shown that the polarization J is depending directly proportional on the filler fraction x and the magnetic field strength is proportional to 1/x. The permeability of the soft magnetic composites was determined experimentally and compared to existing mathematical models. Results show that the permeability can not be predicted by conventional models. A reason for the bad predictability of the permeability of soft magnetic composites are demagnetizing fields within the magnet core which reduce the permeability dramatically. By use of the experimental data of polarization, coercivity and inner demagnetization factor a new model for calculating the permeability of soft magnetic composites has been proposed which shows a good congruence with experimental data. Hence, a prediction of the expectable permeability values is possible from now on.
Additional optimizations of the composites by mixing different soft magnetic particles, by using varying mean particle sizes and by specific alignment of the particles have been studied and found to have potential for applying.Lesen Sie die deutsche Zusammenfassung auf Kunststoffe.de
Soft magnetic composites; polymer-particle composites; highly filled polymers; functional polymers; magnetic properties; permeability; loss dissipation; coercivity; polarization
Institute / chair: Fakultät für Natur- und Materialwissenschaften der Technischen Universität Clausthal
Technical consultant for expert services: Dr.-Ing. B. Weidenfeller (Betreuer, Prof. Dr. rer. nat. Dr.-Ing. habil. W. Riehemann
Publication year: 2008
Provider: Wissenschaftlicher Arbeitskreis Kunststofftechnik (WAK) / Kunststoffe.de
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