Directly obtained tau-phase MnAl, a high performance magnetic material for permanent magnets
2016 (English)In: Journal of Solid State Chemistry, ISSN 0022-4596, E-ISSN 1095-726X, Vol. 237, 300-306 p.Article in journal (Refereed) PublishedText
The metastable tetragonal iota-phase has been directly obtained from casting Mn0.54Al0.46 and (Mn0.55Al0.45)(100)C-2 using the drop synthesis method. The as-casted samples were ball milled to decrease the particle size and relaxed at 500 degrees C for 1 h. The phase composition, crystallographic parameters, magnetic properties and microstructure were systematically studied. The results reveal that the iota-phase could be directly obtained from drop synthesis. The highest M-s of 117 emu/g was achieved in the (Mn0.55Al0.45)(100)C-2 where the iota-phase was stabilized by doping with carbon. Carbon doping increased the c/a ratio of the tau-phase as it occupies specific interstitial positions (1/2, 1/2, 0) in the structure. Furthermore, ball milling increases the coercivity (H-c) at the expense of a decrease in magnetic saturation (M-s). The increase in coercivity is explained by a decrease of grain size in conjunction with domain wall pinning due to defects introduced during the ball milling process.
Place, publisher, year, edition, pages
2016. Vol. 237, 300-306 p.
Permanent magnets, Rare-earth free, High temperature synthesis, Diffraction, Magnetic measurements
Chemical Sciences Physical Sciences Engineering and Technology
IdentifiersURN: urn:nbn:se:uu:diva-294651DOI: 10.1016/j.jssc.2016.02.031ISI: 000373661100041OAI: oai:DiVA.org:uu-294651DiVA: diva2:932655
FunderSwedish Energy AgencySweGRIDS - Swedish Centre for Smart Grids and Energy Storage