Influence of a quantity and dielectric type on dielectromagnetics properties
Dominika Gaworska*, Bogumił Węgliński*, Mikołaj Szafran**, Paweł Wiśniewski** *Politechnika Wrocławska, Instytut Maszyn, Napędów i Pomiarów Elektrycznych, ul. Smoluchowskiego 19, 50-372 Wrocław **Politechnika Warszawska, Wydział Chemiczny, Zakład Technologii Nieorganicznej i Ceramiki, ul. Noakowskiego 3, 00-664 Warszawa
Quarterly No. 1, 2005 pages 46-50
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abstract Dielectromagnetics are powder composites which are more and more widely used as magnetic cores for electric devices. The paper present basic parameters of dielectromagnetics obtained by employment of new kinds of dielectrics i.e. compositions: water-glass-NaOH, Glifos-NaH2PO4, water-glass-NaH2PO4; and binders: „Tarflen” dispersion, poly(acrylic-styrene) dispersion, poly(vinyl-buthyral) emulsion and Flumix C, obtained as the result of die pressing under high value pressure values. Studies on parameters of the composites were conducted in two stages: initial tests and core tests. In initial tests the binder content was equal 5 wt.%. In core tests, binder content was decreased to 1 wt.% in relation to the iron powder in order to investigate the influence of the components’ amount on the properties of magnetic cores. Magnetic tests were conducted on ring samples with dimensions φ60φ50x5 mm, which were obtained using die pressing method under 800 MPa. In initial tests the samples were heated in temperature of 200ºC/0.5 h (samples PUB-5%, DT-5%, PAS- 5%), 600ºC/0.5 h (samples SWNa-5%, PF-5%, Glifos-5%, FLC-5%, SP-Glifos-5%, SPNa-5%), depending on the kind of binder used. The initial magnetic tests of composites (Figs 1, 2) resulted in a selection of only the SWNa, Glifos and SPNa samples for further research. Subsequently, samples were heated in 800ºC/1 h in order to check thermal strength of the binder and of the dielectric. Unfortunatelly, high increase of total energy loss was observed, what indicated that insulating properties of the binder had been annihilated because of the influence of high temperature (Fig. 2). In core tests, samples were heated at 500ºC/0.5 h (SWNa-1%, Glifos-1%, SPNa-1%) and they later underwent magnetic tests. Reduction the binder’s amount results in better magnetic parameters (Figs 5, 6). The research shows that the kind of the binder used and its amount has an effect on dielectromagnetics’ parameters and the most beneficial properties were indicated for SPNa-1% composite, which was characterized by the lowest total energy lost (Fig. 7). Key words: dielectromagnetics, dielectrics, soft magnetic powders, binders, magnetic properties