Ferrite Technology Research Articles

Review on Ferrites and its Application for Environmental Remediation

During the recent couple of years, there has been an increased level of interest in ferrites. The attractive electrical, optical and different properties of ferrites made them center of attraction because of their utilization in different day to day applications, for example, energy devices like supercapacitors and batteries, water treatment, sun based energy gadgets and attractive liquids. This is the review paper about the ferrites, their current status and development of ferrite technology which is used in various day to day applications.

INTEGRATED USE OF MAGNETITE IN ENVIRONMENTAL PROTECTION MEASURES

The object of research: magnetite obtained by using the ferritic method for the purification of iron-containing solutions. Problem to be solved: a comprehensive solution to the problem of using magnetite, obtained as a result of using the ferrite method for purifying iron-containing solutions, as a catalyst for the oxidation of carbon monoxide and its further utilization in the production of building materials. The main scientific results: it has been shown that the magnetite precipitate formed during the processing of pickling solutions by the ferrite method can be used as a cheap, affordable and effective catalyst for the oxidation of carbon monoxide from flue gases of industrial enterprises, the disposal of which after long-term use does not create problems due to its stability and inertness. Field of practical use of research results: the use of the ferrite method in the purification of pickling solutions of metallurgical enterprises provides not only an increase in the efficiency of water purification, but also leads to the introduction of waste-free technology. The decisive factor will be the use of magnetite as sludge of the use of ferrite technology to solve the problem of reducing flue gas emissions from the production of electrodes for the metallurgical industry, which include toxic carbon monoxide. Innovative technology product: waste-free technology for the processing of pickling solutions by the ferrite method with the formation of a product with magnetic and catalytic properties, further processing of which consists in using red lead iron as a pigment in the production of building materials. Scope of the innovative technology product: oxidation of carbon monoxide from industrial flue gases, followed by the use of red lead as a pigment.

The removal of Cu(II)–EDTA chelates using green rust adsorption combined with ferrite formation process

Classical adsorbents such as activated carbon are inefficient to remove Cu(II)-EDTA in solution. Moreover, the heavy metals in the generated sludge can easily be dissolved back into solution. In this research, a novel strategy developed by coupling green rust adsorption and ferrite formation technology was proposed for Cu(II)-EDTA chelate removal. At the adsorption stage, green rust sulfate (GRME(SO42−)) showed a high adsorption efficiency of chelated copper, with a capacity of 126.41 mg g−1, compared to other classical adsorbents. During the ferrite formation stage, GRME(SO42−)-based precipitate with high moisture content and slow settling rate could be transformed into ferrite-based precipitate with low moisture content and rapid settling rate. The volume and moisture content of ferrite were 2.20 and 1.45 times lower than those of GRME(SO42−) and the sedimentation velocity of ferrite was also 1.23 times higher than that of GRME(SO42−), which strongly demonstrated the necessity of the ferrite formation process. Toxicity characteristic leaching procedure (TCLP) test results showed that the metallic copper of GRME(SO42−) sludge could be more easily dissolved back into solution than that of ferrite precipitate under weak-acid conditions, indicating the stability of ferrite. In addition, after the ferrite process, the generated sludge exhibited soft magnetism and could be quickly separated within few seconds using an external magnetic field. All these results showed that the combined green rust adsorption with ferrite formation method was an efficient, recyclable and eco-friendly method for the treatment of wastewater containing Cu(II)-EDTA.

Simulation Experimental Study on Ferrite Rolling Process of Low-Carbon Steels

In this paper, the Steel Plate Heat Commercial (SPHC) that produced by RiZhao Steel’s Endless Strip Production (ESP) line was taken as the research object. The phase transition points under different cooling rates were measured by DIL805A thermal expansion instrument and then the static Continuous Cooling Transformation (CCT) curve was plotted. The rolling process of ferritic zone was simulated by Gleeble-3800 hot compression tester. The microstructure evolution of SPHC under different temperatures and different strain rates were analyzed, and the hot compression deformation behavior was studied. The experimental result has shown that when the cooling rate of low carbon steel is lower than 15 °C·s-1, the microstructure is mainly composed of ferrite and a small amount of pearlite and tertiary cementite. The experimental material showed a mixed crystal phenomenon when the deformation reached 50% at 780 °C. The fitting calculation has shown that the deformation activation energy of the ferrite zone rolling is 112 kJ·mol-1, and the relationship between the deformation energy storage and the temperature compensation strain rate factor was established. Subsequently, the above experimental results were verified in the RiZhao Steel’s ESP line, which laid the experimental foundation for the use of ferrite rolling technology for endless strip production.

Cobalt-Based Ferrites Characterization Using Two Different Terahertz Time-Domain Spectrometers

We report an experimental study of the electrical properties of manganese cobalt (MnCo) and nickel cobalt (NiCo) ferrites in the terahertz (THz) frequency band. The study is motivated by the potential of MnCo, NiCo, and other magnetic ceramics for the fabrication of active and passive devices for THz wave communications. Using two different terahertz (THz) time-domain spectroscopy systems, we characterized the optical constants of cobalt ferrites doped with manganese and nickel in the technologically important 0.2–1 THz frequency band. The MnCo and NiCo ferrites investigated in our study exhibit a lower refractive index and absorption coefficient in the 0.2–1 THz frequency band than commercial strontium ferrite. We observed that using different valency ion oxide leads to a sudden change of the refractive index as a function of sample stoichiometries. Our experimental results provide evidence that microwave ferrite technology can be extended to the THz frequency band.

PWM power supply for ICRF ferrite tuner in EAST

Ion cyclotron resonance frequency (ICRF) heating is a traditional auxiliary heating method applied to EAST. However, the antenna load will oscillate violently with the change of plasma parameters in the ICRF heating. But fast ferrite branch technology (FFT) can be used to achieve real-time impedance matching by controlling the bias magnetic field of FFT to adjust its equivalent electric length. So an excitation coil power supply is developed to satisfy the requirement of fast and stable change of FFT bias magnetic field. In the power supply design, the method of Pulse Width Modulation is used to achieve rapid real-time conversion of current, and to meet the needs of rapid power conversion. The paper introduces general design of PWM power supply, front DC power supply, energy storage filter circuit and constant current circuit of H bridge sequentially. And an experiment is set on the FFT excitation coil current changing with the control signal, indicating that the rapid real-time current conversion can be achieved.

A Ferrite LTCC-Based Monolithic SIW Phased Antenna Array

In this paper, we present a novel configuration for realizing monolithic substrate integrated waveguide (SIW)-based phased antenna arrays using Ferrite low-temperature cofired ceramic (LTCC) technology. Unlike the current common schemes for realizing SIW phased arrays that rely on surface-mount component (p-i-n diodes, etc.) for controlling the phase of the individual antenna elements, here the phase is tuned by biasing of the ferrite filling of the SIW. This approach eliminates the need for mounting of any additional RF components and enables seamless monolithic integration of phase shifters and antennas in SIW technology. As a proof of concept, a two-element slotted SIW-based phased array is designed, fabricated, and measured. The prototype exhibits a gain of 4.9 dBi at 13.2 GHz and a maximum $E$ -plane beam-scanning of ±28° using external windings for biasing the phase shifters. Moreover, the array can achieve a maximum beam-scanning of ±19° when biased with small windings that are embedded in the package. This demonstration marks the first time a fully monolithic SIW-based phased array is realized in Ferrite LTCC technology and paves the way for future larger size implementations.

Study of ICRF Ferrite Tuner

This paper describes the analysis following the breakdown of an ion cyclotron radio frequency (ICRF) tuner purchased from Advanced Ferrite Technology (AFT). The codes used in the analysis were CST and COMSOL. These codes use the standard gyromagnetic model for the ferrite, which gives results that are largely in error when compared with measurements at ICRF and at lower hybrid frequencies. We have measured a slab of the ferrite used in the ICRF tuner provided by AFT and from these measurements we have constructed a tabular model of the ferrite and inserted it into the COMSOL code. The results give performance that closely agrees with the performance specifications issued by AFT. We then used this modified code to correlate the simulation with the destructive evidence found in the tuner. The correlation was good between the destruction spot and the peak of the standing electric field. Pictures of the destruction and the heating in the tuner and the standing field results from the simulation are given.

ChemInform Abstract: Preparation of Nanoferrites and Their Applications

AbstractReview: 393 refs.

Composition, microstructures, and magnetic properties of Bi-modified NiCuZn-ferrite for low temperature Co-fired ceramic application

The effects of Ni2+ and Bi3+ substitution on the microstructural development and magnetic properties of low-temperature-fired NiCuZn ferrites with nominal compositions of NixCu0.21 Zn0.79−xBiyFe2−yO4 (x = 0.1–0.5, y = 0–0.05) were investigated in order to develop low-temperature-cofired ferrite technology and to produce high-frequency devices with a multilayer process. For the Bi-modified NiCuZn ferrites, increasing x decreased the average grain size due to lattice contraction; meanwhile, the saturation flux density first increased and then decreased. We attributed this behavior to the change of superexchange between A-B sites and B-B sites in the spinel structure. We found that Bi3+ ions could enter into the ferrite lattice, which enhanced the grain growth and densification during sintering due to the activation of the lattice. A study of the solid-state reaction kinetics of Bi-modified NiCuZn ferrites revealed that Bi3+ modification decreased the early activation temperature and the ferrite formation temperature; thus, Bi3+ modification could reduce the activation energy of the solid-state reaction. The Bi-substituted samples with x = 0.35 and y = 0.02 had compact, uniform microstructures, and high sintering densities, leading to relatively high values of permeability and Q-factor.

Preparation of nanoferrites and their applications.

Ferrites have a plethora of applications in the myriad fields of technology. Ferrites are widely used in conventional electronic, electrical, and magnetic devices. For the past two decades, since the discovery of the superparamagnetic nature of nanostructured ferrites, their applications in biotechnology and biomedical sciences as well as in advanced electronics and microwave devices have gained immense attention. In this review, the historical development of ferrite science and technology, and the synthesis methods for ferrite nanoparticle preparation and their applications have been discussed. Various synthetic methods with typical examples, their advantages as well as limitations have been discussed in details. Traditional industrial applications of various ferrites have also been discussed citing relevant patents. Recent developments on nanoferrite research in terms of synthetic methods as well as advanced applications have been discussed elaborately.

Academician Andrey Mikaelian — the founder of waveguide ferrite technology

The full Member of Russian Academy of Sciences, Doctor of Engineering, Professor, laureate of Lenin prize, State prize of the Russian Federation, State prize of the Armenian Soviet Socialist Republic and Lomonosov prize, the chevalier of SPIE Gold Medal (the higher award of the International Society for Optical Engineering), A.S. Popov Gold Medal of the Russian Academy of Sciences-such was the incomplete list of regalia and awards of A.L. Mikaelian, the Chief scientist of JSC "Radio Engineering Corporation "Vega".

Experimental Results of a Cost-Effective Ozone Generator for Water Treatment in Colombia

Obtaining high-quality cost-effective water, minimizing the public health risk generated by pathogenic elements or disinfection sub-products such as trihalomethane and/or chlorophenol, has made necessary the use of technologies different to chlorination. In this paper, we present the implementation of a high-voltage, high-frequency flyback inverter to generate ozone, and outline the main characteristics and uses of a prototype of water ozonation from a well for a hospital in Colombia. With the prototype, the ozone dose can be adjusted through the duty cycle modulation; switching was done with a Mosfet and the voltage signal was increased with a ferrite technology transformer. The source is characterized by its simplicity, good performance and low cost.

High-quality radio-frequency inductors on silicon using a hybrid ferrite technology

We have realized millimeter-size rf inductors on silicon using a polyimide mold–copper electroplating coil technology. Subsequently, the coils are assembled with magnetic cover plates of commercially available bulk Ni–Zn ferrites of high resistivity. Using the magnetic flux-amplifying ferrite plates, we obtain a 40% enhancement of the inductance and a 25% enhancement of the quality factor (Q=10–20) for frequencies up to 0.2 GHz. Our results indicate the large potential of using bulk ferrites for rf applications in a hybrid inductor assembly process.

Ferrite Properties and Technology Issues for Improved Microwave Systems

ABSTRACTMicrowave device engineers continually seek materials advances to improve performance of magnetic components at reduced size and cost. Wherever possible, microstrip or stripline device configurations are adopted in preference to bulky waveguide structures. In radar and communications applications, the nonreciprocal propagation properties of ferrites are essential for realizing phase shifters, circulators, isolators, and power limiters. The introduction of superconductor circuits has led to the development of very low-loss phase shifters and circulators. Recent demonstrations of tuning reciprocal rf permeability by varying the state of magnetization at very low magnetic fields has led to the development of high-speed, high-Q tunable filters. In this paper, design issues of four classes of microwave device are reviewed from the standpoint of their ferrite material requirements: (1) low-loss microstrip phase shifters (2) microstrip tunable resonators, (3) self-biased microstrip circulators with normal or in-plane uniaxial anisotropy, and (4) high-power quasi-optical circulators.

Microwave firing of MnZn-ferrites

Microwave firing is evaluated in comparison to conventional firing for MnZn-ferrites. For otherwise identical conditions, microwave firing results to higher densities and coarser microstructures. Initial magnetic permeability values (25 kHz, 25 °C, <0.1 mT) after conventional firing are approximately 5000, but the corresponding values after microwave firing are approximately 6000. Unlike the conventional firing process, the final density after microwave firing is increased by increasing the prefiring temperature. As appears from the results of this study, microwave firing could be in principle a promising MnZn–ferrite firing technology for materials to be used in high magnetic permeability applications. No advantages of microwave firing are evident for materials intended to be used in high field power applications.

Ferrite devices and materials

The development and current status of microwave ferrite technology is reviewed in this paper. An introduction to the physics and fundamentals of key ferrite devices is provided, followed by a historical account of the development of ferrimagnetic spinel and garnet (YIG) materials. Key ferrite components, i.e., circulators and isolators, phase shifters, tunable filters, and nonlinear devices are also discussed separately.

Microwave applications of soft ferrites

Signal processing requires broadband, low-loss, low-cost microwave devices (circulators, isolators, phase shifters, absorbers). Soft ferrites (garnets, spinels, hexaferrites), applied in planar microwave devices, are reviewed from the point of view of device requirements. Magnetic properties, specific to operation in high-frequency electromagnetic fields, are discussed. Recent developments in thick film ferrite technology and device design are reviewed. Magnetic losses related to planar shape and inhomogeneous internal fields are analyzed.

ChemInform Abstract: Advanced LTCC Ferrite Technology for Low Cost Phase Shifters in Emerging RF Systems

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Properties of ferrites at low temperatures (invited)

At cryogenic temperatures magnetic properties of ferrites change significantly from their values at room temperature, which has been the main regime for most device applications. Recently, microwave ferrite devices with superconducting microstrip circuits have been demonstrated at a temperature of 77 K with virtually no electrical conduction losses. Conventional ferrimagnetic garnet and spinel compositions, however, are not generally optimized for low temperatures and may require chemical redesign if the full potential of these devices is to be realized. Saturation magnetizations increase according to the Brillouin–Weiss function dependence that is characteristic of all ferromagnetic materials. Increased magnetocrystalline anisotropy and magnetostriction can have large effects on hysteresis loop squareness and coercive fields that are essential for stable phase shift and efficient switching. Rare-earth impurities and other ions with short spin-lattice relaxation times can cause increased microwave losses. In this article, the basic magnetochemistry pertaining to ferrites will be examined for adaptation of ferrite technology to cryogenic environments.