The Structure and Magnetic Properties of Rapidly Quenched Fe72Ni8Nb4Si2B14 Alloy

Abstract

The complex structural and magnetic studies of the annealed rapidly quenched Cu-free Fe72Ni8Nb4Si2B14 alloy (metallic ribbons form) are reported here. Based on the calorimetric results, the conventional heat treatment process (with heating rate 10 °C/min and subsequent isothermal annealing for 20 min) for wound toroidal cores has been optimized to obtain the least lossy magnetic properties (for the minimum value of coercivity and magnetic core losses at 50 Hz). For optimal conditions, the complex permeability in the 104–108 Hz frequency range together with core power losses obtained from magnetic induction dependence up to the frequency of 400 kHz was successfully measured. The average and local crystal structure was investigated by the use of the X-ray diffraction method and the transmission electron microscopy observations and proved its fully glassy state. Additionally, for the three temperature values, i.e., 310, 340 and 370 °C, the glass relaxation process study in the function of annealing time was carried out to obtain a deeper insight into the soft magnetic properties: magnetic permeability and cut-off frequency. For this type of Cu-free soft magnetic materials, the control of glass relaxation process (time and temperature) is extremely important to obtain proper magnetic properties.

Influence of Cu Content on Structure, Thermal Stability and Magnetic Properties in Fe72−xNi8Nb4CuxSi2B14 Alloys

“…It is interesting to note that the highest values of µ correspond to materials with 1.6 at.% and 0.6 at.% Cu content (minimum of Gibbs free energy). It is also worth paying attention to the positive effect of the Cu addition on the magnetic properties in comparison with Cu-free counterpart (Fe 72 Ni 8 Nb 4 Si 2 B 14 alloy) studied in our previous work [33]. The materials obtained in this work have higher Bs values and lower Ps values in the entire tested frequency and magnetic induction range.…”

“…It was noticed that with increasing temperature, reflections corresponding to the α-Fe phase begin to appear and at 560 °C the α-Fe peaks have higher intensities and become narrower. [33] 370 3100 5.07 × 10 5…”

“…The present study describes the effect of Cu substitution in Fe 72−x Ni 8 Nb 4 Cu x Si 2 B 14 alloys on thermodynamic parameters, crystallization kinetics, crystal structure, and magnetic properties. Our initial chemical composition is based on the multi-component alloy Fe 72 Ni 8 Nb 4 Si 2 B 14 , which was described in the previous work [33]. The heat treatment of this material has been optimized in order to obtain the lowest possible core power losses.…”

TEM, HREM, L-TEM Studies of Fe-Based Soft Magnetic Melt-Spun Ribbons Subjected to Ultra-Rapid Annealing Process

“…they are also known to have low eddy current losses, due to high electric resistance and formability to a thickness of approximately 25 μm. thus, many efforts have been made to improve the magnetic properties of different groups of soft magnetic materials like Fe-si-B-nb-Cu (FineMet) [1], Fe-M-B (nAnOPeRM) [2][3][4][5][6], Fe-Co-M-B (hitPeRM; M = nb, zr, hf) [7], Fe-Co-nb-B-P (PyROPeRM) [8] and Feni-based [9][10][11][12]. soft magnetic nanocrystalline alloys are often obtained by thermal annealing of amorphous alloys, however, their magnetic properties are sensitive to chemical composition as well as microstructure.…”