Amorphous Alloy Ribbons Research Articles

Impact of Ion Bombardment on the Structure and Magnetic Properties of Fe78Si13B9 Amorphous Alloy

Amorphous Fe78Si13B9 alloy ribbons were bombarded by ion beams with different incident angles ( $$ \theta $$ ). The evolution of the microstructure and magnetic properties of ribbons caused by ion beam bombardment was investigated by x-ray diffraction, transmission electron microscope and vibrating sample magnetometer analysis. Low-incident-angle bombardment led to atomic migration in the short range, and high-incident-angle bombardment resulted in the crystallization of amorphous alloys. Ion bombardment induces magnetic anisotropy and affects magnetic properties. The effective magnetic anisotropy was determined by applying the law of approach to saturation, and it increased with the increase of the ion bombardment angle. The introduction of effective magnetic anisotropy will reduce the permeability and increase the relaxation frequency. Excellent high-frequency magnetic properties can be obtained by selecting suitable ion bombardment parameters.

Magnetization Processes in Ribbons of Soft Magnetic Amorphous Alloys

Using iron-based (Fe–B–Si–C; Fe–Ni–Si–B) and cobalt-based (Co–Fe–Ni–Cr–Mn–Si–B) soft magnetic alloys as examples, we have studied the dependences of the remanence measured using minor hysteresis loops on the maximum induction. The different degrees of stabilization of the 180° and 90° domain walls allows these dependences to be used to analyze the magnetization processes that occur in the rapidly quenched soft magnetic alloys. It has been established from the Br(Bm) dependences that, in the ribbons of soft magnetic amorphous alloys, the processes of the rotation of the magnetization oriented perpendicular to the ribbon plane start before the end of the processes of the displacement of the walls of domains with planar magnetization. After the end of the magnetization rotation processes, the magnetization processes can be interpreted as the displacement of the domain walls with a planar magnetization accompanied by a decrease in their number and a transition to a bistable state.

Iron-Based Amorphous Magnetic Properties by Ni Content Tuning and Isothermal Treatment

In this work, we have developed a series of amorphous alloy ribbons of Fe75Co4B13Y4Nb4-xNix(x=0, 0.5, 1, 2, 3 and 4) which were prepared by industrial purity alloy. Besides, the effects of Ni substitution and isothermal annealing on the saturation magnetization (Ms) and intrinsic coercive force (jHc) were systematically investigated. The SQUID-VSM data pointed out the Mshas been increased by Ni content addition with largest enhanced by 57 % from 114 emu/g to 180 emu/g. After quickly annealing at the optimal temperature, the Msreached 199 emu/g and jHcdecreased from 50 Oe to 33 Oe. DSC measurements displayed that this system has a multi-step crystallization in the heating process. Under the premise of maintaining the excellent amorphous forming ability (AFA), the gap between the two crystallization peaks was broadened with Ni addition, which is good to the forming of α-Fe phase at the annealing treatment. And this was also consistent with the X-ray diffractometer (XRD) results. The Scherrer formula calculated results suggested that isothermal annealing has significant effect on size of α-Fe nanocrystals in annealing process, which obvious affect the Msand jHc. The annealing temperature and time can not only affect the precipitation of nano-crystalline, but also control the grain size. Hence, an appropriate annealing process is very important to improve the properties of these iron-based nanocrystalline magnetic materials. In conclusion, the results will help us to understand the influence of Ni elements and isothermal annealing on the microstructure and magnetic of Fe75Co4B13Y4Nb4-xNixamorphous alloys.

New methods for probing and exploring magnetoelastic properties of amorphous ferromagnetic alloys

We describe two new methods for investigating and exploring magnetoelastic properties of ribbons of amorphous magnetic alloys. One consists of exciting the ribbon mechanically while detecting the electromagnetic response, and the second method involves the use of a radiofrequency resonator as a contactless technique for measuring magneto-impedance [C. A. Grimes, S. C. Roy, S. Rani, and Q. Cai, Sensors 11, 2809–2844 (2011)]. The electromagnetic response to mechanical vibration is discussed in connection with the possibility of observing Fano resonance in a classical system, and the magneto-impedance is found to be highly sensitive to magnetic domains formation and their dynamics.

Magnetoelectric effect in ferromagnetic-semiconductor layered composite structures

The results of magnetoelectric effect experimental studies in two different structures based on piezoelectric semiconductor gallium arsenide are presented. The monolithic structure consisted of a gallium arsenide substrate with deposited nickel layer (GaAs-Ni), and the composite structure contained a semiconductor substrate with an amorphous magnetic alloy (GaAs-Metglas) ribbon glued on one side. A quality factor Q ≈ 23500 and magnetoelectric coefficient of 316 V/Oe.cm were achieved at the frequency of planar acoustic oscillations for GaAs-Ni structure at room temperature.

Magnetoelectric coupling of a magnetoelectric flux gate sensor in vibration noise circumstance

A magnetoelectric (ME) flux gate sensor (MEFGS) consisting of piezoelectric PMN-PT single crystals and ferromagnetic amorphous alloy ribbon in a self-differential configuration is featured with the ability of weak magnetic anomaly detection. Here, we further investigated its ME coupling and magnetic field detection performance in vibration noise circumstance, including constant frequency, impact, and random vibration noise. Experimental results show that the ME coupling coefficient of MEFGS is as high as 5700 V/cm*Oe at resonant frequency, which is several orders magnitude higher than previously reported differential ME sensors. It was also found that under constant and impact vibration noise circumstance, the noise reduction and attenuation factor of MEFGS are over 17 and 85.7%, respectively. This work is important for practical application of MEFGS in real environment.

Change of magnetic properties of (Fe1−x Mn x )75P15C10 amorphous alloys ribbon

Change of magnetic properties of (Fe1−x Mn x )75P15C10 amorphous alloys ribbon

Effects of ozone nanobubles on superior electric storage for anodically oxidized films of Ti-Ni-Si amorphous alloy ribbons

The effects of nanometer-sized bubbles (NBs) of ozone on a superior electric storage capacitor for anodically oxidized films of Ti-15at.% Ni-15at.% Si amorphous alloys were determined in 0.4M H2SO4 solutions with NBs of oxygen and ozone. The Use of ozone NBs accelerates the formation of oxide films at lower than 10V, resulting in uneven surfaces with cavities of 2–10nm in size. The resulting film shows a nearly vertical line in a Nyquist diagram, rapid increases in the imaginary impedance, and a horizontal line near the −90° phase angle in a Bode diagram, demonstrating evidence for use in an electric distributed constant circuit. Further enhancement of the imaginary impedance for the realization of a superior electric storage capacitor is needed.

Cycle rapid cooling treatment effect on the magnetic properties and giant magnetoimpedance properties of Co-based amorphous alloy ribbons

The influence of cycle rapid cooling treatment on the giant magnetoimpedance (GMI) properties in Co-based amorphous alloys was investigated. Hysteresis loops show that the saturation magnetization of ribbons has been improved by cycle treatment. It can be found that the GMI ratio was increased from 89% to 130% at 1MHz by the thermal cycle (TC) treatment. Moreover, GMI ratio of TC treatment sample increased up to 321% at 5MHz. It is considered that internal thermoelastic stress leads to surface roughness, magnetic domain structures and saturation magnetization changes of the ribbons during different cycle processes. It was also found that the asymmetric GMI (AGMI) phenomenon occurred in the Co-based alloys with TC treatment after annealing, which can be regarded as a new method to get GMI-valve to improve GMI sensitivity.

Transition to long period stacking ordered structures in Mg85Gd9Zn6 alloys from amorphous ribbons examined by synchrotron radiation scattering: Comparison with Mg85Y9Zn6 alloys

Transition from supersaturated hcp crystals containing solute clusters into long-period stacking ordered structure has been examined by in-situ synchrotron radiation measurements. Amorphous Mg85Gd9Zn6 alloy ribbons were heated at a constant speed of 10K/s, and small-angle scattering and wide angle diffraction profiles were compared with those obtained for Mg85Y9Zn6 amorphous ribbons. Comparison of the developments of microstructures in the two alloys suggested that the key factor that triggers the structural phase transition from hcp to LPSO structure is temperature.

Soft magnetic Fe-Co-based amorphous alloys with extremely high saturation magnetization exceeding 1.9 T and low coercivity of 2 A/m

Extremely high saturated magnetization (Bs) of 1.92 T in conjunction with low coercivity (Hc) of 2 A/m was found to be achieved for (Fe0.8Co0.2)85B14Si1 amorphous alloy. The high Bs above 1.9 T was the first evidence for amorphous alloys. The slight increase of B to 15%B reduces Bs to 1.88 T. The high Bs of 1.92 T is much higher than that (1.63 T) for the new commercial Fe-B-Si-C amorphous alloy and comparable to commercial Fe-Si steels. The excellent soft magnetic properties, which cannot be obtained for all soft magnetic alloys including amorphous, nanocrystalline and crystalline alloys reported to date, were obtained by annealing the as-spun amorphous alloy ribbon for 600 s at 593 K in a magnetic field of 15.9 kA/m. The high Bs above 1.9 T was obtained in a rather wide annealing conditions of 543–603 K and 300–1200 s, indicating the ease of achieving the excellent soft magnetic properties. No appreciable crystalline phase is recognized in the annealed ribbon even by HRTEM and electron diffraction pattern. The effective permeability at 1 kHz also exhibits high values above 20000 and the Curie temperature also shows high values above the onset temperature of crystallization corresponding to high thermal stability of soft magnetic properties. Besides, the (Fe0.8Co0.2)84B15Si1 and (Fe0.8Co0.2)85B14Si1 amorphous alloys exhibit good bending ductility even in the optimal annealed state. The corrosion resistance in 3.5 mass% NaCl aqueous solution is better than that for the commercial Fe-Si-B-C amorphous alloy. The first synthesis of the Fe-based amorphous alloy having simultaneously high Bs above 1.9 T, low Hc of about 2 A/m, high effective permeability, high Tc and good bending ductility is promising for future extension of amorphous alloys as engineering soft magnetic materials.

The Influence of Annealing Temperature on Microstructure and Magnetic Properties of Fe74Co3Si8B10Al1Nb4 Amorphous Alloy Ribbons

Multi-component alloy ribbons with a composition of Fe74Co3Si8B10Al1Nb4 were prepared by a single roller melt-spinning method. The alloy had a fully amorphous structure, as determined by X-ray diffraction. The alloy ribbons were annealed for 10 min at temperatures of 350, 400, 450, 500, 550 and 600 oC, respectively. Differential scanning calorimetry curves indicated that the glass transition temperature (Tg) and the supercooled liquid range (ΔTx) of the amorphous alloy ribbon were about 494 oC and 43 oC, respectively. The ribbons showed soft magnetic properties, with a Curie temperature (Tc) at 284 oC, high saturation magnetization (Ms) of 1.18 T, and coercive force (Hc) of 33.66 A/m. In the present study, both saturation magnetization and coercive force of amorphous alloy ribbons increased with increasing the annealing temperature, due to precipitations and growth of α–Fe phase nanocrystals in the amorphous matrix. On the other hand, it was found that the coercive force of alloy ribbons reduced as a consequence of precipitations of Nb3Si phase if the annealing temperature reached 600 oC.

Fe(Co)SiBPCCu nanocrystalline alloys with high Bs above 1.83 T

Fe84.75-xCoxSi2B9P3C0.5Cu0.75 (x=0, 2.5 and 10) nanocrystalline alloys with excellent magnetic properties were successfully developed. The fully amorphous alloy ribbons exhibit wide temperature interval of 145–156°C between the two crystallization events. It is found that the excessive substitution of Co for Fe greatly deteriorates the magnetic properties due to the non-uniform microstructure with coarse grains. The alloys with x=0 and 2.5 exhibit high saturation magnetization (above 1.83T), low core loss and relatively low coercivity (below 5.4A/m) after annealing. In addition, the Fe84.75Si2B9P3C0.5Cu0.75 nanocrystalline alloy also exhibits good frequency properties and temperature stability. The excellent magnetic properties were explained by the uniform microstructure with small grain size and the wide magnetic domains of the alloy. Low raw material cost, good manufacturability and excellent magnetic properties will make these nanocrystalline alloys prospective candidates for transformer and motor cores.

Magnetic Flux Valve: A Magnetoelectric Materials-Based Device for Conversion and Control of Electric Power

This paper introduces a voltage-controlled static magnetic device called magnetic flux valve. It is mainly used in a magnetic circuit to actively control the magnetic flux through the magnetic circuit. The magnetic flux valve has a laminated structure of two different types of layers made of a magnetostrictive material, e.g., amorphous alloy ribbon, and a piezoelectric material, e.g., piezoelectric sheet. The permeability of the magnetostrictive layers changes when an external control voltage applied to the piezoelectric layers changes, which is known as the converse magnetoelectric effect. A permeability change of the magnetic flux valve will lead to a change of the reluctance of the magnetic flux valve and the reluctance of the magnetic circuit containing the magnetic flux valve. As a consequence, the magnetic flux and/or its distribution in the magnetic circuit will change. There is a great potential to use the proposed magnetic flux valve to develop new equipment, such as tunable inductor and adjustable-voltage-ratio transformer for more flexible conversion and control of electric power in many applications. This paper presents the concept, magnetic properties, working principles, and applications of the magnetic flux valve.

Effect of Mo addition on the thermal stability, microstructure and magnetic property of FeCoZrBCu alloys

Fe80-xCoxZr10-yMoyB9Cu1(x = 10, 20, 30; y = 0, 2) amorphous alloy ribbons prepared by a single roller melt spinning were annealed at different temperatures. The thermal stability, microstructure and magnetic property of FeCoZr(Mo)BCu alloys were investigated by differential thermal analysis (DTA), X-ray diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). Mo additions have a large effect on the thermal stability, microstructure and magnetic property of alloys. Mo additions decrease crystallization activation energies of FeCoZrBCu alloys. Mo additions affect the distribution of Co element, simplify the crystallization process and improve the thermal stability of coercivity (Hc).

Crystallization Kinetics in Cu<sub>64.5</sub>Zr<sub>35.5</sub> Binary Metallic Glass

The crystallization kinetics of melt-spun Cu64.5Zr35.5 amorphous alloy ribbons was investigated using differential scanning calorimetry (DSC) at different heating rates. Besides, the Kissinger and isoconversional approaches were used to obtain the crystallization kinetic parameters. As shown in the results, the activation energies for glass transition and crystallization process at the onset, peak and end crystallization temperatures were obtained by means of Kissinger equation to be 577.65 ± 34, 539.86 ± 54, 518.25 ± 20 and 224.84 ± 2 kJ/mol, respectively. The nucleation activation energy Enucleation is greater than grain growth activation energy Egrowth, indicating that the nucleation process is harder than grain growth. The local activation energy Eα decreases in the whole crystallization process, which suggests that crystallization process is increasingly easy.

ВЛИЯНИЕ УЛЬТРАЗВУКОВОЙ МЕХАНОАКТИВАЦИИ НА КИНЕТИКУ КРИСТАЛЛИЗАЦИИ И МАРТЕНСИТНЫЕ ПРЕВРАЩЕНИЯ АМОРФНОГО СПЛАВА НА ОСНОВЕ TiNi

The influence of ultrasonic mechanical activation on the amorphous alloys is practically unstudied. The influence of ultrasound on crystallization of TiNi-based amorphous alloy ribbons, their structure and properties formation has not been investigated up to the present moment. Being in the crystalline state, TiNi-based amorphous alloys experience the thermoelastic martensitic transformations, which are the basis for manifestation of unusual mechanical properties – shape memory effect. Amorphous shape memory alloys are the advanced materials that experience thermoelastic martensitic transformations after crystallization. Such materials are used as the basis for the creation of crystalline materials with the specified parameters of crystalline structure or for producing the amorphous and crystalline composites. The goal of this work is the study of ultrasonic mechanical activation influence on the crystallization kinetics and martensitic transformations of an amorphous shape memory alloy using the differential scanning calorimetry (DSC) method. The ultrasonic mechanical activation was carried out using two methods: in the waveguide of longitudinal ultrasonic vibrations and in the ultrasonic anvil. During the first method of the ultrasound mechanical activation, the amorphous ribbon was fixed in the waveguide of longitudinal vibrations and experienced ultrasonic irradiation of various durations. To initiate ultrasonic vibrations, the authors used the UZDN-2T ultrasonic low-frequency dispergator with the frequency of 22 kHz. During the second method, the amorphous ribbon is placed horizontally and the vertically placed waveguide is applied using contact process. Such method is used for the surface strengthening of metals and alloys. To initiate the ultrasonic vibrations, the authors used the UZG 1-1 ultrasonic generator. Ti 50 Ni 25 Cu 25 amorphous ribbons were selected as a subject of the study. Calorimetric measurements were carried out using the Mettler Toledo 822e differential scanning calorimeter. The obtained data showed that in the result of ultrasonic mechanical activation, temperatures and energies of crystallization and martensitic transformations change that can be the evidence of size reduction of a crystalline phase grain.

Numerical Investigation of the Air Flow Effects on Amorphous Alloy Ribbon Formation

During the amorphous ribbon production process, the mechanisms that cause uneven thickness and herringbone on two surfaces of the ribbon are very complicated. The high velocity rotating roller causes periodic air eddies near the surface and air flow around the contact zone. The air flow might be the major reason that causes the non-uniformity thickness and the ripples. In this paper, a two-dimension model was developed to simulate the air flow eddies and a three-dimensional simulation was performed for the air flow field around the puddle zone. Simulation results show that the higher velocity of air flow around the puddle edges is closely related to thicker ribbon rim. The continuous air eddies along the roller surface and the air flow fluctuations along the roller width are the major reasons causing non-uniform convective heat transfer during ribbon solidification. The frequency of air eddy matches well with the nominal ripple frequency along the ribbon length, and the air flow fluctuation coincides with the herringbone wavelength along the ribbon width. The influences of the air flow on cooling, ribbon thickness, and herringbone phenomena are all discussed here.

Effects of Crystallization on the Corrosion and Passivity of Amorphous Pd-Fe-Co-Si-B Alloys

Corrosion behavior of Pd48.2Fe17Co16.7Si13.4B4.7 and Pd51.4Fe18Co18Si11.1B1.5 alloys was examined by potentiodynamic polarization tests in pH 8.5 buffer solution. The amorphous alloy ribbons showed passivity with the passive current densities of 2 × 10−6 A/cm2~4 × 10−6 A/cm2. The crystalline alloys showed a higher corrosion rate in pH 8.5 buffer solution with the degree of variation depending on the alloy composition. It is suggested from the Mott-Schottky analysis that the donor density was lower for the amorphous alloy than the crystalline alloy.

A flexible, wave-shaped P(VDF-TrFE)/metglas piezoelectric composite for wearable applications

In this work, a wave-shaped piezoelectric composite (WSPC) made of fine β-phase vinylidene fluoride trifluoroethylene copolymer (P(VDF-TrFE)) polymer and high-elastic FeSiB amorphous alloy (metglas) ribbon has been successfully fabricated for wearable device applications. X-ray diffraction and the Fourier Transform Infrared Spectrum studies reveal P(VDF-TrFE) exhibiting the fine β-phase. Both theoretical analysis and experimental results show that unique wave-shaped structure enhances the electromechanical coupling significantly, because of the combination piezoelectric effects of d33 and d31 modes in P(VDF-TrFE) polymer, as well as the enhanced effective piezoelectric coefficient caused by the pre-stretch in P(VDF-TrFE) film. Two application examples of WSPC, (i) mechanical force sensor or energy harvester, and (ii) the medical blood-pressure pulse sensor, have been investigated, which show that the WSPC is a promising candidate for future wearable device applications.