Soft magnetic properties of the Fe72Co10Nb6B12 amorphous alloy

Artur Chrobak 1Grzegorz Haneczok 2Piotr Kwapuliński 2Dariusz Chrobak 2Zbigniew Stokłosa 2Józef Rasek 2

1. University of Silesia, Institute of Physics, Uniwersytecka 4, Katowice 40-007, Poland
2. University of Silesia, Institute of Material Science, Bankowa 12, Katowice 40-007, Poland

Abstract

It was shown [1] that soft magnetic properties of the Fe86-xNbxB14 (x=2-8) amorphous alloys can be improve by 1 h annealing at temperatures close to the crystallization temperature. Such an optimization annealing causes an increase of initial magnetic permeability μ (for the best alloy x=6, μ=3x 104), and a reduction of coercive field (1-3 A/m). The observed effect was attributed to annealing out of free volume leading to formation of small iron clusters. An unfavorable effect of the high Nb content is a relatively low Curie temperature (390 K) which can be improved by a partial replacing of Fe by Co.

The aim of the paper is to study magnetic properties, crystallization and the optimization effect of the Fe72Co10Nb6B12 amorphous alloy for which the Curie temperature was determined as 515 K. Magnetic properties were studied by making use of: permeability measurements (Maxwell-Wien bridge, f=1 kHz, H=0.5 A/m), magnetic after-effect Δμ/μ (Δμ=μ(t1=30s)-μ(t2=1800s), t1, t2 times after demagnetization), coercive field Hc (permalloy probe) and magnetization curves (fluxmeter).

It was shown that soft magnetic properties can be optimized by 1 h annealing at 675 K. For optimized samples μ=104 and Hc=15 A/m. The crystallization was examined by applying measurements of magnetization (magnetic balance) with heating rates 3-10 K/min and derivation scanning calorymetry (5-20 K/min). The activation enthalpy of the nanocrystallization was determined as 3.8 eV.

[1] G.Haneczok, A.Chrobak, P.Kwapuliński, Z.Stokłosa, J.Rasek, N.Wójcik, Proceedings of International Conference on Soft Magnetic Materials, SMM'16, Düsseldorf September 2003, Verlag Stahleisen GmbH 2004, p.603.

 

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Presentation: poster at E-MRS Fall Meeting 2005, Symposium B, by Grzegorz Haneczok
See On-line Journal of E-MRS Fall Meeting 2005

Submitted: 2005-05-20 06:47
Revised:   2009-06-07 00:44