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PL
W pracy przedstawiono wyniki badań właściwości magnetycznych mieszanki farby drukarskiej z proszkami ferromagnetycznymi, służących do weryfikacji autentyczności dokumentów. Badania eksperymentalne przeprowadzono na próbkach o trzech grubościach powłoki magnetycznej. Na podstawie wartości indukcji i pola magnetycznego określono zależności między grubością farby magnetycznej a jej przenikalnością magnetyczną.
EN
The paper presents the results of testing the magnetic properties of a mixture of printing ink with ferromagnetic powders, used to verify the authenticity of documents. Experimental studies were carried out on samples with three thicknesses of the magnetic coating. Based on the values of induction and magnetic field, the relationship between the thickness of the magnetic paint and its magnetic permeability was determined.
PL
W pracy przedstawiono wyniki badań właściwości magnetycznych farby drukarskiej domieszkowanej proszkiem żelaza. Badania eksperymentalne przeprowadzono na próbkach o trzech grubościach powłoki magnetycznej: 0,2, 0,25 i 0,3 mm. Uzyskane wartości indukcji i pola magnetycznego posłużyły do określenia zależności pomiędzy grubością farby magnetycznej a jej przenikalnością magnetyczną. Analiza właściwości powłok została uzupełniona o matematyczny opis zależności pomiędzy parametrami materiałowymi a histerezą w materiałach magnetycznych. Zaproponowana eliptyczna aproksymacja histerezy znacznie ułatwia projektowanie i prognozowanie właściwości gotowych wyrobów.
EN
The paper presents the results of testing the magnetic properties of printing ink doped with iron powder. Experimental studies were carried out on samples with three thicknesses of the magnetic coating: 0.2, 0.25 and 0.3 mm. The obtained values of induction and magnetic field were used to determine the relationship between the thickness of the magnetic paint and its magnetic permeability. The analysis of coating properties was supplemented with a mathematical description of the relationship between material parameters and hysteresis (Measurements and modeling of ferromagnetic properties of printing inks used to secure documents).
EN
Al-Y-Fe amorphous and nanocrystalline alloys are characterized by a unique collection of diverse properties that are influenced by various factors, including heat treatment. In this paper, the effect of heat treatment on the structural changes and selected properties of Al-Y-Fe metallic glasses in the as-spun state is investigated. The structure of the Al88Y7Fe5 and Al88Y6Fe6 alloys was examined by X-ray diffraction (XRD) and Mössbauer spectroscopy (MS). The corrosion resistance of the samples was characterized using polarization tests in a 3.5% NaCl solution at 25 °C. The effect of sodium chloride on the surface was studied with scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). The magnetic properties of Al-based alloys were explored using a vibrating sample magnetometer (VSM). It was revealed that the tested alloys show better properties after annealing than in the as-spun state. The annealing of the Al88Y7Fe5 and Al88Y6Fe6 alloys in the temperature range of 200 to 300 °C improved the magnetic properties and corrosion resistance of these materials. After 3,600 s, the better EOCP values were recorded for the Al88Y6Fe6 and Al88Y7Fe5 alloys after annealing at 300 °C and 200 °C, adequately. On the basis of the polarization tests, it was concluded that the electrochemical properties are better for Al88Y6Fe6 alloys after annealing at 300 °C.
EN
This work deals with the characterization of structure, magnetic and mechanical properties of (FeNiCo)100-x(AlSi)x (x = 0, 5, 10, 15, 25) multicomponent alloys prepared by casting. The results of X-ray diffraction measurements, scanning electron microscopy observations and hardness and magnetic properties investigations are presented. The studies show that cast (FeNiCo)100-x(AlSi)x alloys reveal dendritic morphology and their phase composition depends on (Al + Si) content. For x ≤ 10 a face-centered cubic phase is observed, while the increase of Al and Si content results in a body-centered cubic phase formation. It leads to a fivefold increase of hardness from 88 HV to 526 HV. The investigated alloys have high magnetic induction reaching 170 emu/g, while their coercivity value is even up to 2.9 kA/m for x = 15, and strongly depends on chemical and phase composition.
EN
This work reported the successful synthesis of ilmenite-spinel (1 − x)NiTiO3-xMnFe2O4 (x = 0, 0.05 and 0.10) composites by a simple sol-gel method. Phase formation of composites was analyzed by the X-ray diffraction method. All the synthesized samples formed diphasic ilmenite-ferrite composites without any trace of impurity or intermediate phase. The optical properties of synthesized composites were characterized by diffuse reflectance UV–visible spectroscopy. MnFe2O4 phase modified the optical band gap of NiTiO3 material and shifted its optical bandgap value toward lower energy. Ferroelectric and magnetic hysteresis loops were investigated at room temperature. The hysteresis loops indicated the typical ferromagnetic and ferroelectric nature of all composites at room temperature. In P-E loops, the remanent polarization (Pr) and saturation polarization (Ps) showed a slight increase in the sample with 5% MnFe2O4 phase addition. However, the lossy P-E loop was observed in the sample with the addition of 10% MnFe2O4. The presence of ferrite MnFe2O4 phase in NiTiO3 material enhanced the magnetic properties of NiTiO3 at room temperature. The M-H loops of NiTiO3-MnFe2O4 composites presented a ferromagnetic behavior with a dramatic increase in saturation magnetization with an increase of ferrite phase addition.
EN
The influence of microwave (MW) plasma on magnetization and morphology of sol-gel synthesized MnFe2O4 ferrite nanoparticles is investigated in this study. Manganese (II) nitrate hexahydrate, ferric (III) nitrate nanohydrate and citric acid were used to synthesize ferrite nanoparticles via a facile sol-gel route. These ferrite nanostructures were heat-treated at 700ºC and then given MW plasma treatment for 10 min. The pristine MnFe2O4 and plasma treated MnFe2O4 showed almost similar structural formation with a slight increase in crystallinity on plasma treatment. However, XRD peak intensity slightly increased after plasma treatment, reflecting better crystallinity of the nanostructures. The size of the particle increased from 35 nm to 39 nm on plasma treatment. It was challenging to deduce the surface morphology of the nanoparticles since both samples were composed of a mixture of big and small clusters. Clusters that had been treated with plasma were larger in size than pristine ones. The band gap energy of the pristine MnFe2O4 sample was about 5.92 eV, which increased to 6.01 eV after treatment with MW plasma. The saturation magnetization of MnFe2O4 sample was noted about 0.78 emu/g before plasma treatment and 0.68 emu/g after MW plasma treatment.
EN
The process of mechanical cutting of magnetic materials has many advantages in the form of high efficiency with reduced process costs in relation to other cutting technologies; no thermal stresses in the material, which significantly deteriorate the magnetic properties; or the possibility of shaping materials taking into account long cutting lines. In industrial practice, it is very difficult to ensure appropriate conditions for the cutting process and its proper control. Currently, there are no data on the selection of technological parameters of the mechanical shear slitting process of grain-oriented silicon steel in terms of the obtained cutting surface quality and the obtained magnetic properties of the workpiece. The article presents the possibilities of forecasting the characteristic features of the cut edge and selected magnetic properties of grain-oriented silicon steel. For this purpose, proprietary numerical models using FEA (Finite Element Analysis) were used. Then, experimental studies were carried out, and the optimisation task was developed. The developed results enable the correct selection of technological parameters of the process, ensuring the appropriate quality of the cut edge of steel and minimal interference with the magnetic properties.
EN
Samples of Bi1.5Pb0.5(Sr1.8−xKx)CaCu2O8+d and Bi1.5Pb0.5Sr1.8CaCu2O8+dKx have been prepared from powders of carbonates and primary oxides using the solid state reaction method and compared in this study. In the first case, potassium (K) is substituted in the strontium (Sr) site. In the second one, K is added. A part of the paper is devoted to discuss the results obtained by X-ray diffraction (XRD) analysis and scanning electron microscope (SEM) observations of (Bi,Pb)2Sr1.8 CaCu2O8+d samples doped by potassium to provide additional microstructural information related to the doping method. These analyses are supplemented by resistivity and magnetic measurements. Results show how the rate of doping by potassium affects transport and magnetic properties of Bi(Pb)2212 phase. The critical current density (Jc) is improved using the two methods and it reaches a double value by the addition of K as compared to the undoped sample.
10
EN
Though normal air cooling and green sand mold-casted gray iron convey an essentially pearlitic matrix, ferritic gray iron is used in some electro-mechanical applications to have better magnetic properties, ductility, and low hardness. Conventionally, to produce ferritic gray iron, foundryman initially produces pearlitic gray iron, then it is carried through a long annealing cycle process for ferritic transformation. This experiment is conducted to eliminate the long annealing cycle from the conventional process. A process is developed to produce as-cast ferritic gray cast iron by air cooling in the green sand mold. In this experiment, Si content is kept high, but Mn content is kept low based on sulfur content; a unique thermodynamic process is established for decreasing the Mn content from the melt. After a successful preconditioning and optimum foundry return charging, the melt is specially inoculated, and metal is poured into the green sand mold. An extra feeder is added for slowing down the cooling rate where casting thickness is around 15mm. Finally, hardness and metallographic images are observed for final confirmation of the ferritic matrix.
EN
The purpose of studying the properties of zinc-manganese nanoferrite was to compare organic fuels that were produced in conditions created by the auto gel combustion method, using citric acid, glycine, and urea with different pH values: (citric acid = 6, glycine = 3 and urea = 0). The samples were prepared in stoichiometric ratios to gain Mn0.5Zn0.5Fe2O4, and all the samples were calcined in the same condition (500 °C and 30 minutes). It should be noted that the entire process of synthesis was photographed to analyze the effect of fuels during the combustion process. Combustion reactions were studied by simultaneous thermal analysis (STA), FT-IR spectroscopy, and X-ray diffraction (XRD), also the Rietveld method was used to determine the type and amount of crystalline phases. Magnetic properties of the samples were measured by vibration sample magnetometer (VSM), and their morphology and powder agglomeration was observed by field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). Superior magnetic properties of the sample synthesized with glycine were achieved. Urea gave the smallest particle size, while citric acid produced intermediate properties.
12
EN
Magnetostrictive TbxHo0.8−xPr0.2Fe1.8Mn0.1 (0 ⩽ x ⩽ 0.20) alloys are prepared by arc-melting and subsequent annealing. The dopant of Pr/Mn introduced into RFe2 compounds effectively stabilizes the forming of single C15 Laves phase at ambient pressure. The easy magnetization direction (EMD) varies when Tb content increases, which is accompanied by a crystalstructural transition. EMD lies along ‹1 0 0› axis for x ⩽ 0.05, rotating to ‹1 1 1› axis for x ⩽ 0.12, with a tetragonal symmetry changing to a rhombohedral one. Magnetocrystalline-anisotropy compensation is obtained with the optimized composition of x = 0.12, shifting to the Tb-poor side in comparison to Pr/Mn-free counterpart. An enhanced effect on magnetoelastic properties is achieved in Tb0.12Ho0.68Pr0.2Fe1.8Mn0.1, which simultaneously possesses a low anisotropy and high magnetostriction performance, i.e. λs ~ 420 ppm, λ111 ~ 970 ppm, and a large low-field λa ~ 390 ppm/2 kOe, being 30 % higher than that of Pr/Mn-free compound. Combining low-cost light rare earth Pr with the lower Tb content, Tb0.12Ho0.68Pr0.2Fe1.8Mn0.1may make it promising solution in magnetostrictive applications.
EN
Pseudobrookite (Fe2TiO5) is a semiconductor with numerous potential applications. Low-grade ilmenite ore has been used as an inexpensive source of Fe and Ti for preparation of Pseudobrookite. Ilmenite was first leached with 20% hydrochloric acid for 3 h at 70°C. Co-precipitation of soluble Fe and Ti from the rich filtrate was carried out at pH ≥ 9.1 followed by calcination at different temperatures (900-1300oC) for 2 h. X-ray diffraction patterns (XRD) showed that a single-phase nanocrystalline pseudobrookite powder was produced. The pH was a critical parameter for the evolution of formation the different sizes, structural morphology, and the magnetic properties of the product. Scanning electron microscope (SEM) images showed that particles synthesized at pH 11.2 contained more agglomerations and were more porous than those synthesized at pH 9.1. As the calcination temperature increases, the Fe2TiO5 changes from a small rod-like structure to an elongated rod-like structure, and finally to interconnected aggregated crystals. The magnetization of the synthesized Fe2TiO5 was measured using a vibrating sample magnetometer (VSM) and was found steadily increase with increasing calcination temperature from 1000 (≈9 emu/g) to 1300°C (16 emu/g). Such a large saturation of magnetization might be due to the high phase purity and well-defined crystallinity of Fe2TiO5.
14
EN
The effect of electrodeposition potential on the magnetic properties of the FeCoNi films has been reported in this paper. The FeCoNi electrodeposition was carried out from sulfate solution using potentiostatic technique. The obtained FeCoNi films were characterized by X-ray diffractometer (XRD), atomic absorption spectrometer (AAS) and vibrating sample magnetometer (VSM). It has been shown that the electrodeposition potential applied during the synthesis process determines the magnetic characteristics of FeCoNi films. The more negative potential is applied, the higher Ni content is in the FeCoNi alloy. At the same time, Co and Fe showed almost similar trend in which the content decreased with an increase in applied potential. The mean crystallite size of FeCoNi films was ranging from 11 nm to 15 nm. VSM evaluation indicated that the FeCoNi film is a ferromagnetic alloy with magnetic anisotropy. The high saturation magnetization of FeCoNi film was ranging from 86 A·m2/kg to 105 A·m2/kg. The film is a soft magnetic material which was revealed by a very low coercivity value in the range of 1.3 kA/m to 3.7 kA/m. Both the saturation magnetization and coercivity values decreased at a more negative electrodeposition potential.
EN
The present study, aims to investigate the effect of minor Zr and Nb alloying on soft magnetic and electrical properties of Fe86 (Zrx Nb1-x )7B6 Cu1 (x=1, 0.75, 0.5, 0.25) alloys. The investigated alloys were prepared through the melt spinning process. Within the examined compositional range (Nb up to 5.25 at%, respectively), the soft magnetic properties and electrical resistivity of the alloys continuously increase with increasing Nb content. However increasing the Nb content further decreases such properties. We could confirm the influence of ratio of Zr and Nb on grain growth and crystallization fraction during crystallization by using the soft magnetic properties and electrical properties.
PL
W pracy przeprowadzono analizę wpływu materiału osnowy na właściwości magnetyczne miękkich materiałów kompozytowych (SMC). Badania przeprowadzono na próbkach rdzeni cylindrycznych wykonanych przez autorów z mieszaniny proszku żelaza i różnego rodzaju osnowy. Badania obejmowały wyznaczenie takich parametrów jak indukcja nasycenia Bs, natężenie koercji Hc i stratność. Pomiary wykonano przy różnej częstotliwości wymuszenia.
EN
Soft magnetic composites are often used in the design of electromagnetic converters and electrical machines. Their popularity is due to the ease of molding and the ability to adapt to specific applications. The paper presents magnetic properties of cores made of iron powder and different type of binder. Samples were prepared by compression in temperature dependent from binder / Fe powder mix. Measurement of magnetic parameters revealed an change in magnetic properties with using various types of binders. The presented measurement data show that it is possible to produce of SMC cores with good magnetic properties, using readily available components and in uncomplicated production processes. Cylindrical cores were made with different types of binders, respectively: powder of suspense polyvinyl chloride, powder of polytetrafluoroethylene, powder of polyethylene wax and transformer oil. For the prepared samples we have determined their basic magnetic properties. The analysis of collected measurement data showed a significant relationship between SMC sample forming parameters and their magnetic properties. In addition, the measurements showed a poor dependence of the magnetic properties in developed SMC samples on the excitation frequency. The method of producing a polymer-metal composite described in the article is the subject of patent application P.420850.
EN
Single-phase Eu3S4 was obtained via CS2 gas sulfurization of Eu2O3 nanospheres at 773 K for longer than 0.5 h. The primary particle size of Eu3S4 became larger than that of Eu2O3 during the sulfurization process. Pure synthetic Eu3S4 powders were unstable and transformed to EuS at 873 K under vacuum. Eu3S4 compacts were sintered in temperature range of 773 K to 1173 K and they transformed to EuS at 1473 K during spark plasma sintering. Specific heat of sintered Eu3S4did not show an anomalous behavior in the range of 2 K to 50 K. The magnetic susceptibility of polycrystalline Eu3S4 followed a Curie-Weiss law from 2 K to 300 K. Magnetization of polycrystalline Eu3S4 was larger than that of single crystal Eu3S4 when the magnetic field was less than 3.5 kOe.
EN
The AISI 430 stainless steel with ferritic structure is a low cost material for replacing austenitic stainless steel because of its higher yield strength, higher ductility and also better polarisation resistance in harsh environments. The applications of AISI 430 stainless steel are limited due to insignificant ductility and some undesirable changes of magnetic properties of its weld area with different microstructures. In this research, a study has been done to explore the effects of parameters of laser welding process, namely, welding speed, laser lamping current, and pulse duration, on the coercivity of laser welded AISI 430 stainless steel. Vibrating sample magnetometery has been used used to measure the values of magnetic properties. Observation of microstructural changes and also texture analysis were implemented in order to elucidate the change mechanism of magnetic properties in the welded sections. The results indicated that the laser welded samples undergo a considerable change in magnetic properties. These changes were attributed to the significant grain growth which these grains are ideally oriented in the easiest direction of magnetization and also formation of some non-magnetic phases. The main effects of the above-mentioned factors and the interaction effects with other factors were evaluated quantitatively. The analysis considered the effect of lamping current (175-200 A), pulse duration (10-20 ms) and travel speed (2-10 mm/min) on the coercivity of laser welded samples.
EN
Paper describes the results of Fe80Si11B9 amorphous ribbon investigation after pulsed laser interference heating and conventional annealing. As a result of interference heating periodically placed laser heated microareas were obtained. Structure characterisation by scanning and transmission electron microscopy showed in case of laser heated samples presence of crystalline nanostructure in amorphous matrix. Microscopy observations showed significant difference in material structure after laser heating – nanograin structure, and material after annealing – dendritic structure. Magnetic force microscopy investigation showed expanded magnetic structure in laser heated microareas, while amorphous matrix did not give magnetic signal. Change of magnetic properties was examined by magnetic hysteresis loop measurement, which showed that the laser heating did not have a significant influence on soft magnetic properties.
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