Magnetic and Electric Properties of FeNbB Melt Spun Ribbons

Abstract

In the paper Fe82Nb2B16, Fe80Nb2B18 and Fe78Nb2B20 amorphous alloys, obtained by melt spinning, were examined. It was shown that the alloys studied in the as quenched state and in the relaxed amorphous state or in nanocrystalline state (after a suitable annealing) belong to very good soft magnetic materials with relatively high resistivity. The influence of annealing on brittleness as well as magnetic and electric properties measured at room temperature was examined. A correlation between sample microstructure (in the as quenched state and after annealing) and different physical properties is discussed. It was shown that the observed changes of relative magnetic permeability can be explained by changes of magnetoelastic energy, concentration of microvoids frozen during production process, effective anisotropy constant and magnetic polarisation.

Optimization of soft magnetic properties and crystallization in FeAgNbSiB, FeAgNbB and FeAgCoNbB amorphous alloys

“…In the system Fe-Si-B-Nb 2 the addition of Ag 0.25 causes an increase of the temperature T op in relation to the system Fe-Nb 2 -Si-B [38]. On the contrary, for the FeNb 2 B 22 and FeNb 2 Co 5 B 18 alloys such increase is not observed.…”

“…Comparing the Curie temperature for the Fe 75.75 Ag 0.25 Nb 2 Si 13 B 9 , Fe 75.75 Ag 0.25 Nb 2 B 22 amorphous alloys with T c of the Fe 76 Nb 2 Si 13 B 9 and Fe 76 Nb 2 B 22 amorphous alloys studied in [23,30] one can conclude that the presence of silver causes a decrease of T c by about 10 and 14 K, respectively. Taking into account the alloys Fe 80 Nb 2 B 18 studied in [30] and the Fe 74.75 Ag 0.25 Co 5 Nb 2 B 18 alloy one can conclude that Co atoms causes an increase of the Curie temperature. It is proper to add that boron atoms play similar role on value of T c as it was discussed in [30], i.e.…”

“…Taking into account the alloys Fe 80 Nb 2 B 18 studied in [30] and the Fe 74.75 Ag 0.25 Co 5 Nb 2 B 18 alloy one can conclude that Co atoms causes an increase of the Curie temperature. It is proper to add that boron atoms play similar role on value of T c as it was discussed in [30], i.e. increase of T c with increase of B concentration.…”

Structural Relaxation in Fe78Nb2B20Amorphous Alloy Studied by Mössbauer Spectroscopy

“…2 allow concluding that the observed optimization effect cannot be attributed to iron nanostructure. The significant increase of permeability is due to annealing out of free volume and a reduction of internal stresses, as it was discussed in [6][7][8][9][10][11][12].…”

“…Such a microstructure averages out magnetic anisotropy and gives an enhancement of magnetic permeability. However, as it was shown at first time in [6] in some alloys the optimization effect can be observed without formation of iron nanograins and can be attributed to annealing out of free volume (frozen into material during fabrication) and a reduction of internal stresses [6][7][8][9][10][11][12]. This effect is especially interesting because it allows obtaining very good soft magnets free of embrittlement -the main disadvantage -of nanostructured magnets.…”