L. Potocký

Crystallization of Fe-RE-B quasi-binary glassy alloys

Abstract A small percentage of rare-earth additives in iron-boron amorphous alloys has a big stabilization effect on the amorphous state. Simultaneous magnetization and electrical resistivity measurements were made to determine the crystallization temperatures. The crystalline products after various isothermal heat treatments were identified by X-ray phase analysis in order to clarify the sequence of the appearance of the products.

Magnetic and stress annealing of Fe80T3B17 amorphous alloys

Abstract The influence of transition metal additives to eutectic Fe-B on the magnetic and stress induced anisotropy was investigated. The results are compared with the same properties of binary Fe-B amorphous alloys and treated by taking into account the chemical and physical properties of the transition metal in question.

Magnetic properties of Fe-B amorphous alloys containing rare earth additives

Abstract The influence of a few per cent rare earth additives to iron-boron amorphous alloy was investigated. Compared with binary Fe-B, changes in Curie temperature, magnetization, coercive force and amorphous-crystalline transition were observed. The role of the atomic size effect and the chemical properties of rare earth in these changes are discussed.

The electronic structure of some Fe-based metallic glasses

Abstract The changes in the valence band spectra and core-level energy shifts due to the transition metal, T( = Cr, W, Co and Pt) are studied in amorphous Fe 80 T 3 B 17 alloys by X-ray photoelectron spectroscopy. The effect of heating on Fe-Cr-B alloys is investigated and the problem of the stability of these alloys is discussed.

Influence of heating on magnetic properties of Fe60Ni20B20 amorphous alloys

Abstract The coercive force and the initial magnetic permeability of amorphous Fe60Ni20B20 ribbons heated at temperatures too low to cause any crystallization have been investigated. The observed variations of magnetic quantities are discussed in the relationship to the changes of the internal stresses and to the topological reorganization of the amorphous structure.

Influence of coatings on the magnetic properties of Fe-B metallic glasses

Abstract Electroinsulating coatings based on boric acid and its salts as well as on orthophosphoric acid were developed and applied to Fe-B metallic glasses. Investigations were performed to study the influence of such coatings on the magnetic properties, especially the magnetization curve and magnetization losses.

Rapid annealing of metallic glasses under tension

Abstract Pulse heat treatment using 0.4 s current pulses was applied to Fe 80 B 14 Si 6 amorphous ribbons above its Curie temperature in order to avoid magnetically induced anisotropy. After relaxation the pulse heat treatment was continued while applying 128 MPa mechanical stress to obtain induced anisotropy. The results of pulse annealing were monitored by coercive force and effective anisotropy measurements carried out between the pulses at room temperature. It is shown that pulse annealing enables a magnetically soft relaxed state to be achieved and if mechanical stress is applied during the process, induced anisotropy can be developed.

Magnetic after-effect in quasi-eutectic Fe80TM3B17 metallic glasses

Abstract The influence of a small amount of transition metal additives on iron-boron was investigated by magnetic after-effect measurements. Following stress relaxation, an increase was sometimes found in the amplitude of the after-effect; this is in contradiction with the free-volume concept.

Influence of heat treatment on magnetic properties of amorphous Fe-Ni-B-Si alloys

Abstract The thermomagnetic curves and temperature dependence of the coercive force of amorphous Fe 47 Ni 25 B 18 Si 10 ribbons has been investigated. A relatively high Curie temperature and a good temperature stability of the amorphous state was observed. The mechanism of the amorphous-crystalline transformation is discussed.

Induced magnetic anisotropy of Fe-X-B glassy alloys☆

Abstract The anisotropic properties of Fe-Ho-B and Fe-W-B metallic glasses were investigated. Anisotropy was determined from the energy required to obtain magnetic saturation on the samples as-quenched and annealed without and with external magnetic field. The anisotropy of magnetically annealed Fe-W-B decreases with increasing tungsten concentration whereas this tendency was found in Fe-Ho-B amorphous alloys for higher holmium content only.