The influence of pressing conditions on SrFe12O19 nano-particles

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The influence of pressing conditions on SrFe12O19 nano-particles

Anna Zink Mortensen, Marian Stingaciu, Mogens Christensen
Aarhus University

Permanent magnets have great importance for many technological applications. Today researchers try making new and cheap magnets without rare earth elements. Strontium hexaferrite, SrFe12O19, is an important permanent magnet because of its large anisotropy, good performance/cost ratio, and high stability.
By hydrothermal synthesis platelet-like single-domain nanoparticles can be made. It is possible to control the particle sizes varying time, temperature, and pressure which highly influence the magnetic properties.
The platelet-like particles makes it possible to align the powder in the same direction giving a higher net magnetization. One challenge is to optimize the pressing conditions in order to maximize the remanence and thus the energy product.
In present work the SrFe12O19 powder was made in an autoclave and was analysed by X-ray diffraction and Rietveld Refinement to determine particle size.
The powder was pressed using Spark Plasma Syntering system at different conditions in order to investigate how the pressing conditions influence the magnetic properties. It was found, that pressing at 950oC leads to a much better alignment than pellets pressed at room temperature. Furthermore, ball milling seems to decrease the degree of alignment and thereby the magnetic remanence which leads to a lower energy product. The magnetization was characterized using Vibrating Sample Magnetometer. By applying an external magnetic field before pressing, the alignment is heightened and an increase in energy product at more than 20% can be reported.
Original languageEnglish
Publication year7 Jun 2015
Number of pages1
Publication statusPublished - 7 Jun 2015

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