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

Abstract

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

Production and Properties of Soft Magnetic Cores Made From Fe-Rich FeSiBPCu Powders

“…Traditionally, W is composed of classical eddy current loss (W e ) and hysteresis loss (W h ), and is defined as; W = K h fB n + K e f 2 B 2 . Here, f is the frequency, B is the peak flux density, and K h and K e are hysteresis and eddy current loss coefficients, respectively [13]. The K e is inversely proportional to electrical resistivity of the core.…”

Static and dynamic behavior of domain walls in highBSsoft magnetic ribbons tuned by the annealing temperature

“…The soft magnetic ribbons have important applications in the creation and distribution of efficient electrical power because of their unique advantage in generation of high magnetic flux density (B) and low magnetic core loss [1][2][3][4][5][6]. Demand in real life applications over the years led to Co substitution by a small proportion in place of Fe to form wide ribbons of Fe-Si-B-P-Cu (NANOMET) without losing the high value of B S [7][8][9].…”

Enhanced anisotropy and study of magnetization reversal in Co/C60 bilayer thin film

“…Spinterface is the gateway between two layers through which polarized spins can be transferred. It is a special type of interface having properties which are significantly different from their constituent layers [4][5][6] . The coupling between a FM and OSC molecule at the interface may promote FM state in the OSC layer [7][8][9][10][11] .…”