Papers by Keyword: Amorphous Ribbon

Abstract: The scientific as well as applied approach to addressing the problem of the particle’s liquid state structure should rely on experimental data related to the particular liquid; take into account the temperature interval of its existence, the history and the main aims of the investigation. Taking into account the concept of the quasi-chemical model of the liquid micro-non-uniform composition and the research made on the physical properties of the Fe-based melts being crystallized, the unique technology of the melt time-temperature treatment has been developed. Amorphous ribbons produced using this technology require optimal annealing temperatures to be specifically selected. The results of studying nanocrystalline magnetic core’ properties and their structure in the course of annealing at temperatures below and above the optimal ones are presented. In the amorphous ribbon obtained in the mode of preparation of the melt with overheating above the critical temperature, an enhanced value of the enthalpy of crystallization is found. After the heat treatments of the cores, the mode with overheating the melt above the critical temperature results in higher magnetic properties.

Abstract: This paper presents experiments regarding the welding with electron beam of Ni based amorphous ribbons produced by "Planar flow casting" method with the aid of "Politehnica" University of Timisoara equipment. Welded samples were performed in partnership with Graz University of Technology, Institute of Materials Science, Joining and Forming, using the electron beam welding equipment “Chamber Machine EBG 45-150 K14”. The welded joints were analyzed by SEM, EDX, XRD in order to optimize some technological parameters to avoid deterioration of the amorphous ribbons during the welding process.

Abstract: Taking into account the concept of the quasi-chemical model of the liquid micro-non-uniform composition and the research made on the physical properties of the Fe-and Co-based melts being crystallized, the unique technology of the melt time-temperature treatment has been developed. Amorphous ribbons produced using this technology require optimal annealing temperatures to be specifically selected. The results of studying nanocrystalline magnetic core’ properties and their structure in the course of annealing at temperatures below and above the optimal ones are presented.

Abstract: The HTS-42 (High Temperature Solder) properties in the liquid state have been studied. The optimal operating conditions for the solder melt time-temperature treatment, used for producing amorphous ribbons having the specified service properties, are recommended based on the analysis of the anomalies properties and temperature polytherms shape. The subsequent thermal treatment of soldered joints is not shown appropriate for soldering homogeneous melts not hardened by age (precipitation) hardening. The strength of such products can be improved by increasing the contact joint area. The HTS-42 solder amorphous ribbons enable, as compared to the powder semi-finished product, reducing its consumption by 2-3 times, improving the carrying capacity of soldered constructions by 20-40 %, which makes the soldering practice resource saving and significantly improves the product reliability.

Abstract: Cooling copper roller is the key technology and equipment to amorphous ribbon forming. Rolling bearing support is difficult to obtain high rotation accuracy. A new inner pressure feedback hydrostatic journal bearing is proposed with different recess area. The load capacity and film stiffness mathematical model of hydrostatic journal bearing are established. The Inner pressure feedback hydrostatic journal bearing with different recess area at the diameter of 200mm is designed and manufactured for amorphous ribbon cooling copper roller support structure. The operation tests demonstrate that the rotation accuracy of the cooling copper roller shaft is less than 2μm, which in accordance with the requirements of amorphous ribbon production process.

Abstract: In this study, the coil-less fluxgate effect in Co₇₁Fe₁Mo₁Mn₄Si₁₄B₉ amorphous ribbon was investigated. The coil-less fluxgate is a new type of fluxgate sensor without a coil. It is based on helical anisotropy and deep circumferential magnetic saturation in the ferromagnetic fluxgate core. Coil-less fluxgate measurements were performed in as-cast and annealed ribbons at 480 mA current with 3, 12.5 and 25 rad/m torsion. The second harmonic of the output voltage detected from the ends of the wire show a linear variation in the low magnetic field region. The sensitivity of the current annealed ribbons in the presence of 25 rad/m torsion is about 570 V/T, which is comparable with previously reported fluxgate sensitivity values. The presented sensor has no coil so it is much easier to reduce the size of the sensor and easy to fabricate it.

Abstract: Investigated AC frequency and the number of coil turns as well as their influence on the magnetic induction effect of rare-earth La modified FeSiB amorphous ribbon. The results show that the magnetic induction effect is increased with the increase of AC frequency and the number of coil turns, and changing amplitude of magnetic induction effect shows first increased and then decreased with increasing frequency and coil turns.

Abstract: Prepared rare-earth La modified amorphous ribbon by doping Rare-earth La in Fe₇₈Si₉B₁₃ amorphous alloy. Investigated rare-earth content and annealing temperature as well as their influence on the magnetic induction effect and its amplitude. The results show that, when magnetic field is less than 1356 A/m, with the increase of Rare-earth content,the magnetic induction effect first increased and then decreased, when the magnetic field strength greater than 1356 A/m, the Rare-earth content influence little on magnetic induction effect, changing amplitude of magnetic induction effect shows first increased and then decreased with increasing Rare-earth content.

Abstract: We present the magnetic characterization of nanocrystalline amorphous ribbons with nominal composition Fe_73.5B₉Si_13.5Mo₃Cu₁, obtained by melt spinning. An annealing treatment was made on the alloys during 10, 20, 40, 50, 60 and 70 minutes at 400°C, in order to induce a nanocrystalline phase. Measurements of magnetization were made to evaluate the coercive field (H_C) as a function of annealing time. Results of vibrating sample magnetometry (VSM) show two important changes: a decrease in H_C value as annealing time increases, until reaching a minimum value of 31 Oe, corresponding to the amorphous ribbon with annealing time of 20 minutes. This behavior indicates a soft magnetic state suggesting a structural relaxation. At this time, it is observed the best magnetic properties. In the second change, H_C increases until reaching a maximum value of 34 Oe, corresponding to 60 minutes. This increase indicates the onset of nanocrystallization state for the FeMo phase. In order to evaluate the magnetic anisotropy field (H_K), measurements of low field absorption (LFA) were carried up by means of an electronic paramagnetic resonance (EPR) spectrometer modified. The peak-to-peak linewidth (ΔH_PP-LFA) of LFA signal is associated with H_K, therefore H_K can be evaluated during the different annealing times.

Abstract: Properly annealed Ti₅₀Ni₂₅Cu₂₅ amorphous ribbons have excellent shape memory founction, superelastic and internal friction. In this article, recent progress in research on the amorphous alloy ribbons of Ti₅₀Ni₂₅Cu₂₅ preparation method, phase composition, microstructure of the research status were reviewed. The review mainly includes the phase composition, microstructure evolution, supporting the process of structure change and phase change after heat treatment on Ti₅₀Ni₂₅Cu₂₅ crystallized amorphous ribbons.Shortcomings and future researching fields were also pointed out.