Nanocrystallisation mechanisms in FeCuNbSiB-type alloys from comparative HREM, STM, TGM and calorimetric studies

Tonejc, Antun; Ramšak, N.; Prodan, A.; Suriñach, Santiago; Baró, María Dolors

doi:10.1016/s0921-5107(99)00140-3

Cited by 5 publications

(1 citation statement)

References 14 publications

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“…Nano-crystalline alloys have a moderately high B s and low W t . [5][6][7][8][9][10][11][12][13] Among the nano-crystalline alloys, recently developed Fe-rich Fe-Si-B-P-Cu nano-crystalline alloys [14][15][16] exhibit B s (∼1.85 T) close to steels and the W t is also significantly lower than the best known oriented steels. The excellent magnetic properties of nanocrystalline alloys are only known for the material in the form of thin ribbons.…”

Section: Introductionmentioning

confidence: 99%

Sintered powder cores of high B s and low coreloss Fe84.3Si4B8P3Cu0.7 nano-crystalline alloy

2013

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Nano-crystalline Fe-rich Fe84.3Si4B8P3Cu0.7 alloy ribbon with saturation magnetic flux density (Bs) close to Si-steel exhibits much lower core loss (Wt) than Si-Steels. Low glass forming ability of this alloy limits fabrication of magnetic cores only to stack/wound types. Here, we report on fabrication, structural, thermal and magnetic properties of bulk Fe84.3Si4B8P3Cu0.7 cores. Partially crystallized ribbons (obtained after salt-bath annealing treatment) were crushed into powdered form (by ball milling), and were compacted to high-density (∼88%) bulk cores by spark plasma sintering (SPS). Nano-crystalline structure (consisting of α-Fe grain in remaining amorphous matrix) similar to wound ribbon cores is preserved in the compacted cores. At 50 Hz, cores sintered at Ts = 680 K show Wt < 10 W/kg (f = 50 Hz, Bm ∼1 T). Coating/mixing of powders with an insulating agent like SiO2 is shown to be effective in further reduction of Wt at f > 1 kHz. A trade-off between porosity and electrical resistivity is necessary to get low Wt at higher f. In the f range of ∼1 to 100 kHz, we have shown that the cores mixed with SiO2 exhibit much lower Wt than Fe-powder cores, non-oriented Si-steel sheets and commercially available sintered cores. We believe our core material is very promising to make power electronics/electrical devices much more energy-efficient

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