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Microstructure and magnetic properties of nanocrystalline Fe-based alloys

Hasiak M., Miglierin M., Kaleta J., Zbroszczyk J., Fukunaga H.

Materials Science Poland

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2008

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Vol. 26, No. 1

168--172

EN

Microstructure and magnetic properties of nanocrystalline Fe82(Zr4Nb3)B10Cu1 and Fe80(Zr4Mn3)B12Cu1 alloys with different content of the crystalline phase have been investigated. Changes in the microstructure with progressing crystallization were observed by the room temperature Mössbauer spectroscopy. Good soft magnetic properties and frequency characteristics were found in the nanocrystalline Fe82(Zr4Nb3)B10Cu1 and Fe80(Zr4Mn3)B12Cu1 samples with 50-60% of the crystalline alfa-Fe phase.

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Microstructure studies of amorphous and nanocrystalline (Fe1-xCox)85.4Zr6.8-yMyB6.8Cu1 (x = 0 or 0.1, y = 0 or 1, M = Mo, Nb or Nd) alloys

Olszewski J., Zbroszczyk J., Fukunaga H., Ciurzyńska W., Świerczek J., Hasiak M., Perduta K., Łukiewska A., Młyńczyk A.

Nukleonika

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2004

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Vol. 49,suppl.3

79-83

EN

The amorphous and nanocrystalline (Fe1 xCox)85.4Zr6.8 yMyB6.8Cu1 (x = 0 or 0.1, y = 0 or 1, M = Mo, Nb or Nd) alloys were studied using Mössbauer spectroscopy. We have stated that after the low temperature annealing of the samples the decrease of the average hyperfine field due to the Invar effect was observed. This effect is associated with the increase of atom packing density after the annealing of the samples, which may lead to the noncolinear spin state in some regions. This phenomenon was completely suppressed after substitution of 10% of Fe atoms by Co atoms. At early stages of crystallization of the Fe85.4Zr6.8 yMyB6.8Cu1 (y = 0 or 1, M = Mo, Nb or Nd) alloys, the interfacial zone is poor in iron due to diffusion of Zr, B, Nb, Mo and Nd atoms outside regions where á-Fe fine grains are created. However, the iron content in the amorphous matrix is the same as in the as-quenched state. The iron concentration in the interfacial zone of the nanocrystalline alloys obtained by the accumulative annealing depends on the chemical composition of the as-quenched samples. In the nanocrystalline samples obtained by two-step annealing, the iron content in the interfacial layer is higher than in the amorphous matrix.

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Nanocrystallization studies of rapidly quenched Fe85.4-xCoxZr6.8-yNbyB6.8Cu1 (x = 0 or 42.7, y = 0 or 1) alloys

Olszewski J., Zbroszczyk J., Ciurzyńska W., Fukunaga H., Wysłocki B., Perduta K., Łukiewska A., Młyńczyk A., Lelątko J., Świerczek J.

Nukleonika

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2003

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Vol. 48,suppl.1

49-52

EN

The microstructure of amorphous and nanocrystalline Fe42.7Co42.7Zr6.8-xNbxB6.8Cu1 (x = 0 or 1) alloys was investigated. We have stated that the nanocrystalline samples consist of the crystalline alfa-FeCo grains about 8 nm in diameter embedded in an amorphous matrix which is rich in cobalt. From Mössbauer spectroscopy studies we have found that the crystalline alfa-FeCo phase in the nanocrystalline samples obtained by the conventional annealing is atomically ordered. Moreover, the order degree depends on the annealing time. As for the samples partially crystallized during rapid quenching, the crystalline alfa-FeCo phase is atomically disordered.

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Mikrostruktura i właściwości magnetyczne amorficznych i nanokrystalicznych stopów Fe85,4Zr6,8-xMexB6,8Cu1 (x=0,1; Me=Nb, Mo, Nd).

Zbroszczyk J., Olszewski J., Ciurzyńska W., Fukunaga H., Hasiak M., Wysłocki B., Łukiewska A., Lelątko J.

Archiwum Nauki o Materiałach

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2003

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T. 24, nr 4

297-309

PL

W pracy przeprowadzono badania nanokrystalizacji oraz własności magnetycznych, takich jak podatność i jej dezakomodacja stopów: Fe85,4Zr6,8-xMexB6,8Cu1 (Me=Nb, Mo, Nd, x=0 lub 1). Stwierdzono, że w początkowym stadium krystalizacji stopów Fe85,4Zr6,8-xMexB6,8Cu1 (Me=Nb, Mo, Nd, x=0 lub 1) zawartość żelaza w osnowie amorficznej nie ulega zmianie, obserwuje się natomiast zmniejszenie koncentracji żelaza w fazie przejściowej, co spowodowane jest dyfuzją atomów boru i cyrkonu na zewnątrz obszarów, w których fomują się ziarna fazy krystalicznej. Pomimo tego, część atomów boru i cyrkonu pozostaje w fazie krystalicznej i dlatego koncentracja żelaza w fazie alfa-Fe zależy od warunków obróbki cieplnej i rośnie z temperaturą wygrzewania. Stopy Fe85,4Zr6,8-xMexB6,8Cu1 w stanie amorficznym charakteryzują się małą wartością podatności magnetycznej i dużym natężeniem dezakomodacji. Największą wartość początkowej podatności magnetycznej (8500 w temperaturze pokojowej) wykazuje typ nanokrystaliczny Fe85,4Zr5,8Nb1B6,8Cu1.

EN

In this paper, investigations of nanocrystallization and magnetic properties, i.e. the initial magnetic susceptibility and its disaccommodation of the Fe85,4Zr6,8-xMexB6,8Cu1 (Me=Nb, Mo, Nd, x=0 or 1) alloys were performed. It has been stated that in the early stages of crystallization of the Fe85,4Zr6,8-xMexB6,8Cu1 (Me=Nb, Mo, Nd, x=0 or 1) the iron concentration in the amorphous matrix is the same as in the as-quenched state. However, the decrease of iron concentration in the interfacial zone is observed, which is connected with diffusion of B and Zr atoms out of regions where grains are created. In spite of it, part of these atoms remains in alpha-Fe phase. Therefore, the iron concentration in alpha-Fe phase depends on heat treatment conditions and increases with annealing temperature. The Fe85,4Zr6,8-xMexB6,8Cu1 (Me=Nb, Mo, Nd, x=0 or 1) alloys in the amorphous state exhibit the low initial magnetic susceptibility and high intensity of disaccomodation. After partial crystallization of those alloys the largest initial magnetic susceptibility (8500 at room temperature) was found for the nanocrystalline Fe85,4Zr5,8Nb1B6,8Cu1 alloy.