A. Grabias

Phase transformations in the Fe(Co, Ni)ZrB alloys induced by ball milling

Abstract Phase transformations in the FeZrB-based powders induced by high- and low-energy ball milling are investigated by X-ray diffraction and transmission Mossbauer spectroscopy. The structural and magnetic properties of the processed powders are studied as a function of milling time. The influence of Co and Ni additions on the phase transformations is also investigated. X-ray diffraction measurements of the high-energy ball milled powders indicate the formation of the b.c.c. Fe solid solution. Mossbauer results, however, reveal more complex structure of the milled powders, in particular, the formation of an FeZr amorphous phase at the early stages of milling as well as formation of Fe–B phases. The low-energy ball milling is found to be poorly effective in the alloying of the elemental FeZrB-based powders.

Mössbauer study of the nanocrystalline Fe80Ti7B2Cu1 alloy

A combined conversion electron and γ-transmission Mossbauer spectroscopy is applied to investigate the differences in the surface and bulk crystallization of the amorphous Fe8oTi7B12Cu1 alloy. The radio-frequency (rf) induced effects (rf collapse and sidebands) are used to study the magnetic properties (anisotropy fields, magnetostriction) of the amorphous and nanocrystalline phases. Rf-Mossbauer experiment allowed us to distinguish soft magnetic nanocrystalline bcc-Fe phase from the microcrystalline α-Fe.

Magnetic properties of nanocrystalline Fe80Ti7B12Cu1 alloy investigated by the RF-Mössbauer technique

Abstract Magnetic properties of the Fe 80 Ti 7 B 12 Cu 1 alloy in the amorphous and nanocrystalline state are studied by RF collapse and sideband effects. The magnetic anisotropy fields in the amorphous and nanocrystalline phases can be estimated by the RF-Mossbauer technique. The decrease of magnetostriction due to the formation of the nanocrystalline phase is clearly followed from the RF sidebands effect.

Mössbauer and magnetic studies of FeCoNiCuNbSiB nanocrystalline alloys

Abstract Nanocrystalline Fe80-x-yCoxNiyCu1Nb3Si4B12 alloys were prepared by the annealing of amorphous ribbons. Primary crystallization of the alloys annealed at temperatures of between 500 and 550°C was studied by X-ray diffraction and Mössbauer spectroscopy. Magnetic properties of the alloys were investigated using a hysteresis loop tracer and vibrating sample magnetometer. The annealed ribbons are composed of a two-phase nanostructure consisting of bcc Fe-based grains embedded in an amorphous matrix. Conversion electron Mössbauer spectroscopy (CEMS) measurements reveal a more advanced crystallization process in the surface layers when compared with the volume of the ribbons. The degree of saturation magnetization of the nanocrystalline alloys is of about 1.5 T. The coercive field varies from 1.0 to 6.5 A/m and peaks at an annealing temperature of 525°C. Magnetic softening of the nanocrystalline alloys observed after annealing at 550°C is correlated with a volume fraction of the nanocrystalline bcc phase.