Z. Stokłosa

Influence of Alloying Additions on Enhancement of Soft Magnetic Properties Effect and Crystallization in FeXSiB (X=Cu, V, Co, Zr, Nb) Amorphous Alloys

The crystallization and optimization of magnetic properties effects in FeXSiB (X=Cu, V, Co, Zr, Nb) amorphous alloys were studied by applying X-ray diffraction methods, high resolution transmission electron microscopy (HRTEM), resistometric and magnetic measurements. The temperatures of the first and the second stage of crystallization, the 1h optimization annealing temperature and the Curie temperature were determined for different amorphous alloys. Activation energies of crystallization process were obtained by applying the Kissinger method. The influence of alloy additions on optimization effect and crystallization processes was carefully examined.

Crystallization and Optimization of Soft Magnetic Properties Effect in FeSiB, FeNbSiB, FeCuNbSiB, FeCuZrCoSiB Amorphous Alloys

The aim of the present paper is to find correlations between structural changes and electrical, mechanical and magnetic properties in Fe78Si13B9, Fe76Nb2Si13B9, Fe75Cu1Nb2Si13B9, Fe75Cu1Zr1Co1Si13B9, amorphous and nanocrystalline alloys obtained by melt spinning technique. The influence of annealing on material brittleness, magnetic and electric properties was examined. It was found that the optimization of soft magnetic properties effect is a thermally activated process and its diffusion parameters were determined. It was shown that for the alloys containing Cu, Nb and Zr as alloying additions, the optimization process can be attributed to formation of a nanocrystalline phase. In contrast to this for the FeSiB and FeNbSiB alloys the optimization process should be related to the relaxed amorphous phase.

Influence of free volume on magnetoelastic coupling in iron-based amorphous alloys

In this paper, the influence of structural relaxation on magnetoelastic coupling in iron-based amorphous alloys is carefully examined. In order to change free volume content, the as-quenched samples were annealed for 1 h at temperatures corresponding to the structural relaxation. Magnetostriction measurements were carried out at room temperature using the infrared magnetodilatometer. It was shown that both the parallel magnetostriction coefficient λ∥ and the perpendicular magnetostriction coefficient λ⊥ decrease with decreasing free volume content, whereas the saturation magnetostriction λS (proportional to λ∥−λ⊥) remains constant. In contrast, the volume magnetostriction ω strongly depends on free volume content and follows the relation ω∝ m2 (where m is the reduced magnetization). Moreover, it was confirmed that λS can be attributed to one-ion spin correlations, short range in nature.

Magnetic and Electric Properties of FeNbB Melt Spun Ribbons

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.