Магнитный импеданс пленочных наноструктур для оценки полей рассеяния микрочастиц магнитных композитов

Longitudinal giant magnetoimpedance effect of [Fe21Ni79/Cu]5/Cu/[Fe21Ni79/Cu]5 film element was investigated depends on stray magnetic field of epoxy magnetic composite with 30 % weight concentration of iron oxide magnetic microparticles. Configuration of an experiment was a model of thrombus detection in a blood vessel. Stray magnetic field was varied by movement of a magnetic composite above the element perpendicular to the long side. Composite was either magnetized or not to the state of remanence. As the magnetic composite approaches the GMI element, MI ratio curves are smoothed and shifted along the field axis and maximum value of the MI ratio decreases. Magnetic properties of magnetic composite and film element were investigated as well.

Synthesis and characterization of a new magnetic composite MnFe2O4/clay based on a natural clay obtained from Turkestan deposit

The work is devoted to the development of a new method for the synthesis of magnetic composites based on manganese ferrite on a natural clay, coupling with their physico-chemical characterization. In the study, a natural clay of Kazakhstan obtained from the Turkestan deposit was used for the preparation of magnetic composites. The formation of materials with magnetic properties is an urgent task of our time, due to the needs of various applications of magnetically controlled materials for biomedical systems, electronic devices, catalytic and adsorption processes. The advantage of such materials is the ability to control them using a magnetic field for shaking, recovery, induction heating, among others. In this work, samples were prepared by co-precipitation of manganese and iron salts with 5 mol L-1 NaOH over the Turkestan clay (TC). Materials were characterized by various analyses, such as Fourier-Transform infrared spectroscopy (FTIR), X-ray diffractometric analysis (XRD), and elemental analysis. According to the results of physical and chemical studies of the XRD and thermal analysis, kaolinite is the main mineral in the composition of TC. Magnetic adsorbents MnFe2O4/clay with perfect magnetic separation characteristics were successfully obtained by chemical co-precipitation

Characterization of a soft magnetic composite for use in road-embedded wireless-charging systems

The ferrite magnetic core is an integral component of road-embedded wireless charging systems for electric vehicles. However, the brittleness of ferrite makes it susceptible to premature fracture due to cyclic wheel loading from vehicles. This has motivated the development of a soft magnetic composite (SMC) composed of a flexible polyurethane and crushed ferrite as an alternative. An experimental investigation was conducted into the trade-offs between mechanical, thermal and magnetic properties at ferrite volume fractions between 45.9[Formula: see text]vol% and 80.6[Formula: see text]vol%. A comparison was made between measured properties and predictions from analytical models in order to further investigate the characteristics of the composite. The investigation showed a trade-off between the increase in magnetic permeability and the reduction in strain-to-failure as ferrite volume fraction increased. In addition, a large increase in flexural modulus and thermal conductivity, along with a slight increase in flexural strength was observed. More importantly, the strain-to-failure of the composite was 20 times higher than that of ferrite even at the highest volume fraction, indicating that the SMC was successful in providing a more ductile and flexible alternative.

Removal of Zn(II) By Magnetic Composite Adsorbent: Synthesis, Performance, And Mechanism

In this study, L-methionine and nano-Fe3O4 were encapsulated and cured on sodium alginate by the ionic cross-linking method to form magnetic composite gel spheres (SML). The influence of adsorbent dosages, pH, reaction time, and initial ion concentration on the ability of the gel spheres to adsorb Zn(II) was investigated. The experimental results indicated that under the optimum conditions, the maximum amount of Zn(II) adsorbed by the adsorbent gel spheres reached 86.84 mgˑg-1. The experimental results of adsorption indicate that the reaction process of this adsorbent fits well with the Langmuir and pseudo-second-order kinetic models and is a heat absorption reaction. The results of the adsorption investigation of the coexistence system showed that the adsorbent would preferentially adsorb Pb(II), and the adsorption efficiency of Zn(II) decreased when the concentration of interfering ions increased. The structure of this adsorbent and the adsorption mechanism were investigated by Fourier transform infrared spectrometer, thermal gravimetric analyzer, vibrating sample magnetometer, scanning electron microscope, Brunner-Emmet-Teller measurements, and X-ray photoelectron spectroscopy. The results show that this magnetic composite adsorbent is a mesoporous material with superior adsorption performance, and the amino and carboxyl groups on it react with Zn(II) via ligand chelation; the ion exchange effect of Ca(II) also plays a role. The desorption-adsorption experiments of the adsorbent indicated that the adsorption amount of Zn(II) was maintained at a higher level after several cycles, and the loss of Fe was approximately 0.2%. In summary, SML is an ideal adsorbent for environmental protection.

LABORATORY STUDIES OF PROPERTIES OF SOFT MAGNETIC POWDER COMPOSITE MATERIALS

Изучение эффективности использования электротехнических материалов является актуальной проблемой в области изготовления электрических машин. Одним из важнейших аспектов изготовления электрических машин является проектирование магнитной системы машины. В качестве магнитной системы используют магнитопроводы из различных магнитомягких материалов. Эти материалы отличаются магнитной проницаемостью и удельными магнитными потерями. Данные параметры материалов влияют на нагрев, размер, стоимость и эффективность электрической машины. В целях экономии экспериментальная оценка параметров магнитомягких материалов производится на заготовках различных форм и размеров, на специальных измерительных стендах, согласно международным энергетическим стандартам. В данной статье предлагается экспериментальная установка для лабораторных исследований магнитных свойств магнитомягких материалов, методом кольцевых заготовок, в соответствие со стандартом МЭК-60404-6. В составе установки используется только стандартное недорогое оборудование. Необходимый коэффициент формы магнитной индукциидостигается последовательной коррекциейнапряжения вторичной обмотки с помощью цифрового регулятора. Подход к программной реализации алгоритма последовательной коррекции напряжения вторичной обмотки изложен в статье. С помощью предлагаемой установки проведено исследование свойств образца из магнитомягкого композиционного порошкового материала Somaloy 700-3p (800 MPa) и сравнение результатов с каталожными данными производителя. По итогам работы выявлено, что с помощью предлагаемойустановки могут производитьсяизмерения свойств магнитомягких материалов, в соответствие со стандартом МЭК-60404-6 с необходимой точностью. Предлагаемая установка может быть использована как в качестве учебного стенда, так и в качестве измерительной установки для идентификации свойств магнитомягких материалов при проектировании электрических машин. The study of the efficiency of using electrical materials is of great interest in the field of manufacturing electrical machines. One of the most important aspects of the manufacture of electrical machines is the design of the magnetic cores of the machine. Magnetic cores made of various magnetically soft materials are used as a magnetic system. These materials differ in magnetic permeability and specific magnetic losses. These material parameters affect the heating, size, cost and efficiency of electric machines. In order to reduce expenses, the experimental evaluation of the parameters of soft magnetic materials is carried out on samples of various shapes and sizes, on special experimental setups, in accordance with international electrotechnical standards. This article proposes an experimental setup for laboratory studies of the magnetic properties of soft magnetic materials by the method of ring specimens, in accordance with the IEC-60404-6 standard. The setup uses only standard inexpensive equipment. The required shape factor of the magnetic flux density is achieved by sequential correction of the secondary winding voltage using a digital regulator. The approach to the software implementation of the algorithm for sequential correction of the secondary winding voltage is described in the article. The proposed experimental setup was used to study the properties of a sample made of a soft magnetic composite powder material Somaloy 700-3p (800 MPa) and compare the results with the manufacturer's catalog data. Based on the results of the work, it was revealed that the proposed setup can be used to measure the properties of soft magnetic materials in accordance with the IEC-60404-6 standard with the required accuracy. The proposed experimental setup can be used both as a training stand and as a measuring installation for identifying the properties of soft magnetic materials in the design of electrical machines.

Composite Materials Based on Iron Oxide Nanoparticles and Polyurethane for Improving the Quality of MRI

Polyether urethane (PU)-based magnetic composite materials, containing different types and concentrations of iron oxide nanostructures (Fe2O3 and Fe3O4), were prepared and investigated as a novel composite platform that could be explored in different applications, especially for the improvement of the image quality of MRI investigations. Firstly, the PU structure was synthetized by means of a polyaddition reaction and then hematite (Fe2O3) and magnetite (Fe3O4) nanoparticles were added to the PU matrices to prepare magnetic nanocomposites. The type and amount of iron oxide nanoparticles influenced its structural, morphological, mechanical, dielectric, and magnetic properties. Thus, the morphology and wettability of the PU nanocomposites surfaces presented different behaviours depending on the amount of the iron oxide nanoparticles embedded in the matrices. Mechanical, dielectric, and magnetic properties were enhanced in the composites’ samples when compared with pristine PU matrix. In addition, the investigation of in vitro cytocompatibility of prepared PU nanocomposites showed that these samples are good candidates for biomedical applications, with cell viability levels in the range of 80–90%. Considering all the investigations, we can conclude that the addition of magnetic particles introduced additional properties to the composite, which could significantly expand the functionality of the materials developed in this work.