Barium Ferrite Research Articles

M-Type Barium Hexaferrite-Based Nanocomposites for EMI Shielding Application: a Review

The electromagnetic radiation emission at high radio frequency causes electromagnetic interference (EMI) which is a serious issue. EMI shielding materials are necessary to shield the incoming electromagnetic waves to prevent this problem. Hence, the advancement of high-performance EMI absorbers with flexibility, strong absorption, and extensive bandwidth has gained great attention. Recently, M-type barium hexaferrite as EM interference absorber has gained much interest, owing to their high magnetic loss, high saturation magnetization, flexibility, low cost, high Curie temperature, and strong absorption. Furthermore, due to high density, the incorporation of other dielectric loss fillers such as conductive polymers, graphene, and carbon nanotubes are studied as an essential way to improve the microwave’s absorption. In this review, we present the EMI theory and also summarize modern improvements in the fabrication of barium hexaferrite-based materials comprising substituted barium ferrite and chemical integrations with conductive polymers, graphene, CNTs, and multicomponent composites. The key points of increasing the EMI absorption in barium hexaferrite-based materials are to regulate the EM properties, improving the impedance match, and expanded the loss mechanisms.

Supremacy of Magnetic Behaviour in n-Heptane Based M Doped Barium Ferrite (BaFe2O4) Nanoparticles (M: Co, Ni and Mn)

The M doped BaFe2O4 (M—Co, Ni and Mn) nanoparticles were synthesized through auto combustion method by using n-heptane as a surfactant. And also the weight percentage (wt%) of metals such as cobalt, nickel and manganese (10 wt%, 8 wt% and 6 wt%) in BaFe2O4 was optimized. The prominent orientation (212) and (311) of M doped BaFe2O4 is confirmed from XRD especially in 10 wt% of respective metals. The addition of metal doped in barium ferrite specific vibration on 770 and 445 cm−1 in FTIR spectra indicated the formation of M doped BaFe2O4. The influence of n-heptane as a surfactant on morphological change occurred in different metal doped was visualized from FESEM and TEM images. The different morphologies such as spherical, hexagonal platelets and small rectangular bar shaped were observed only by the inclusion of barium ferrite at surfactant medium. The analysis of EDX spectrum reflected the atomic percentage of elemental presence in the samples of M doped barium ferrite. Magnetic properties of these samples were studied by VSM. It revealed that 28.41 emu/g saturation magnetization (Ms) with 1655.64 Oe coercivity (Hc) and also induced ferromagnetic behaviour. The variation of dielectric constant indicated from dielectric study.

Shrinkage, Density and Hardness of Hard Magnetic Material (BaFe12O19) Based on Iron Sand Produced by Conventional Solid-State Reaction Process

This paper presents shrinkage, density and hardness number of hard magnetic (BaFe12O19) based on iron sand produced by conventional solid-state reaction process. Iron sand was mechanically filtered using permanent magnets 35 times. The filtered iron sand was heated at temperatures of 900°C for 5 hours in the furnace and after it was cold and produce Fe2 O3 phase. Powders of Fe2O3 and BaCO3 were mixed and milled in a shaker ball mill up to 3 hours. The powder mixture compacted at a pressure of 2.5, 5 and 7.5 tons and followed by sintering at temparature of 1100, 1150 and 1200°C for 1 hour in the furnace. Shrinkage measurements include diameter and height uses vernier caliper, while density measurements use the Archimedes method. Hardness number obtained with pass vickers hardness testing methods. Barium ferrite ‘s maximum shrinkage and bulk density values were at 7.5 tons compacting pressure and 1200°C sintering temperature where the shrinkage value was 7.44 percent, average shrinkage was 3.49 percent, and density was 4.397 g/cm3. In barium ferrite with a compacting pressure of 7.5 tons and a sintering temperature of 1200 °C which is equivalent to 741 HV the highest hardness value is found. The higher the compacting press and sintering temperature, the greater the importance of bulk density and hardness of the materials.

Electrophysical Properties of Polymeric Nanocomposites Based on Barium Ferrites Modified by Copper Iodide

Electrophysical Properties of Polymeric Nanocomposites Based on Barium Ferrites Modified by Copper Iodide

Microstructure, magnetic, and dielectric properties of Co–Zr co-doped hexagonal barium ferrites based on the sintering temperature and doping concentration

In this work, M-type hexagonal barium ferrites co-doped with Co and Zr atoms were prepared by a solid-phase method based on the sintering temperature and doping concentration. First, the influences of the sintering temperature on the crystal structure, microstructure, and magnetic properties of ferrites were studied. The crystallinity of the materials increases with the sintering temperature and obtaining high density and uniform grain size at 1300 °C, which promotes grain-boundary diffusion and suppresses grain-boundary migration. Second, the dependence of the crystal structure, microstructure, magnetic, and dielectric properties of Ba(CoxZrx)Fe12−2xO19 on the doping concentration (x = 0, 0.2, 0.4, 0.6) was investigated at sintering temperature of 1300 °C. The increase of the crystal parameter c with x value reveals that the ions of Co2+ and Zr4+ successfully replace the Fe3+ ions. Additionally, the co-doping ions of Co2+–Zr4+ promote the grain-boundary migration and result in some large size grain (> 20 mm) that appeared and increased with the doping concentration. The magnetic hysteresis loops reveal the saturation magnetization increases from 60.45 to 68.6 emu/g, and the coercivity decreases from 1800 to 190 Oe with the x increased to 0.6. The dielectric properties measurement displays the Co–Zr co-doping can improve the dielectric and reduce the dielectric loss. The highest value of the real part of permittivity (e′) and the lowest value of the imaginary part of permittivity (e″) can be obtained at a doping concentration of x = 0.4.

Electric Transport and Dielectric Studies of CoFe2O4-BaFe12O19 Nanocomposite

Electric transport properties of cobalt ferrite and barium ferrite composite were studied in the frequency range of 1 Hz to 1 MHz with temperature varying from 100 to 500 °C. The composite with weight ratio 1:1 (CoFe2O4:BaFe12O19) was synthesized by chemical co-precipitation route. Rietveld refined X-ray diffraction analysis revealed pure phase formation of cobalt ferrite, barium ferrite and the prepared composite. For the prepared composite, dual phase refinement procedure was employed. Average crystallite size of CoFe2O4 and BaFe12O19 was observed as 19 nm and 51 nm respectively. The conduction and polarization mechanism in ferrites was explained on the basis of Maxwell–Wagner theory and Koop’s model which reflects the contribution of grain and grain boundaries present in the specimens. The conductivity analysis confirmed the presence of overlapping large polaron tunneling (OLPT) model for conduction.

Operational lifetime increase of the pumping equipment when pumping-out contaminated groundwater

Purpose. Solving the problem of increasing the pumping equipment operational lifetime when pumping-out contaminated groundwater in the iron-ore industry by extracting the hard, abrasive part, using magnetic filters based on permanent ferrite magnets. Methods. To produce spherical hard-magnetic ferrite elements that catch finely-dispersed magnetic and weakly-magnetic abrasive particles when pumping-out contaminated groundwater in the iron-ore industry, barium ferrite powder BaО∙6Fe2O3 is applied, which is usually used for obtaining hard-magnetic ferrites. Spherical elements for filling a magnetic filtering installation are obtained by the method of spheroidizing the barium ferrite powder in a dragee machine. Sintering of spherical granules obtained from barium ferrite powder is conducted in a high-temperature atmospheric electric box furnace. The sintered spherical elements made of hard-magnetic barium ferrite are magnetized using a magnetic pulsed toroidal-shaped setup in a pulsed constant magnetic field. Findings. For continuous pumping-out and purification of contaminated groundwater from magnetic, weakly-magnetic and non-magnetic highly abrasive particles with the help of magnetic filters, a scheme of a filtering installation of two sections is pro-posed. A technology for producing spherical permanent magnets from barium ferrite powder has been developed for a filtering installation, which includes a coarse purification column with hollow-spherical permanent magnets of 16-17 mm in diameter and a fine purification column with full-bodied spherical barium ferrite magnets of 6-7 mm in diameter. Originality.The term of pumping equipment operation is doubled if to eliminate abrasive wear due to the filtering two-section installation by filling with barium ferrite spherical magnets. In the case of changing the filter, idle time is reduced by using the supplementary auxiliary column. The possibility of processing filtration products and their use in the field of construction and metallurgy without environmental pollution is substantiated. Practical implications. The scheme of magnetic groundwater purification in the iron-ore industry is proposed, consisting of a filtering column of coarse and fine purification from abrasive particles. A technology for producing spherical magnets with different diameters has been developed to ensure the quality of the process. The research results allow to increase the operational lifetime of pumping equipment by eliminating abrasive wear, which will lead to significant savings in the replacement and repair of centrifugal pumps. Keywords: pumping equipment, groundwater, wear, barium ferrite, spherical magnet, filter, iron-ore industry

Silver Doped Polyaniline-Graphene Based Barium Ferrite Composite as Humidity Sensor and Photocatalyst

In this work, the response of humidity sensing and dielectric properties of PANI/Ag/graphene/BaFe12O19 (PAGB) composite prepared by chemical interfacial oxidative polymerization method using the ammonium peroxydisulfate as an oxidant is presented. The synthesized PAGB composite was characterized by using FT-IR, XRD, SEM and EDAX techniques. The measured dielectric constant and dielectric tangent loss values were found to decrease with increase in logarithmic frequency. The electrical resistance of the composite was also found to decrease from 2500 MΩ to 7 MΩ, on exposure to a wide range of relative humidity (RH) varying between 10% and 97% RH. This observed decrease is due to capillary condensation of water molecules which cause the changes in electrical conductivity of composite. The synthesized PAGB-50% composite displayed a high sensitivity at low humidity ranging from 20% to 60% RH. The composite has been proved to be a better candidate in the design of humidity sensors. In addition, PAGB composite exhibited efficiency towards the degradation of organic anionic dye, acid orange-8, with high potential of reusability.

Structural and dielectric properties of cobalt ferrite based nanocomposites

Nanocomposites of cobalt ferrite (CoFe2O4) were synthesized using chemical co-precipitation route. For preparing the nanocomposites, cobalt ferrite was combined with strontium ferrite (C/S-1/1) and with barium ferrite (C/B-1/1) in equal weight ratio of 1:1. Dual phase Rietveld refinement procedure was employed for phase analysis of the specimens. Electrical transport properties were investigated within frequency scale 20 Hz–106 Hz at different temperatures ranging from 100 °C to 400 °C. Dielectric permittivity of the composites was found to increase with temperature. Polarization mechanism was attributed to Koop's theory due to the presence of conductive and non-conductive part in ferrite composites. The ac conductivity mechanism in the composites was ascribed to Maxwell-Wagner model. With increase in temperature, C/S-1/1 depicts greater conductivity compared to C/B-1/1.

Multiferroic ceramics based on barium titanate and barium ferrite

Samples of ceramics based on barium ferrite (BF) and barium titanate (BaTiO3) were obtained and studied. We have analyzed the elemental composition of the obtained ceramics. Based on a study of pyroelectric properties and magnetic hysteresis loops, it was shown that the ceramics based on BF and BaTiO3 obtained in this work has magnetic and ferroelectric properties.

Microstructure of composite materials based on barium titanate and barium ferrite

Synthesis and study of the composite ceramic based on barium titanate and barium ferrite were care out. The results of the analysis of the microstructure and phase composition of the obtained multiferroics are presented.

Changes in Magnetic Properties When Manufacturing Cobalt-substituted Barium Ferrite Powder

Changes in Magnetic Properties When Manufacturing Cobalt-substituted Barium Ferrite Powder

Composite Magnetoelectrics Based on Ceramics of Sodium Potassium Niobate and Barium Ferrite

Samples of ceramics based on barium ferrite (FB) and sodium potassium niobate (KNN) are obtained and studied. The elemental composition of the obtained composite is analyzed. A study of pyroelectric properties and magnetic hysteresis loops showed that the composite based on barium ferrite and sodium potassium niobate ceramics obtained in this work had magnetic and ferroelectric properties.

Trastuzumab Modified Barium Ferrite Magnetic Nanoparticles Labeled with Radium-223: A New Potential Radiobioconjugate for Alpha Radioimmunotherapy.

Barium ferrite nanoparticles (BaFeNPs) were investigated as vehicles for 223Ra radionuclide in targeted α-therapy. BaFe nanoparticles were labeled using a hydrothermal Ba2+ cations replacement by 223Ra with yield reaching 61.3 ± 1.8%. Radiolabeled nanoparticles were functionalized with 3-phosphonopropionic acid (CEPA) linker followed by covalent conjugation to trastuzumab (Herceptin®). Thermogravimetric analysis and radiometric method with the use of [131I]-labeled trastuzumab revealed that on average 19–21 molecules of trastuzumab are attached to the surface of one BaFe–CEPA nanoparticle. The hydrodynamic diameter of BaFe–CEPA–trastuzumab conjugate is 99.9 ± 3.0 nm in water and increases to 218.3 ± 3.7 nm in PBS buffer, and the zeta potential varies from +27.2 ± 0.7 mV in water to −8.8 ± 0.7 in PBS buffer. The [223Ra]BaFe–CEPA–trastuzumab radiobioconjugate almost quantitatively retained 223Ra (>98%) and about 96% of 211Bi and 94% of 211Pb over 30 days. The obtained radiobioconjugate exhibited high affinity, cell internalization and cytotoxicity towards the human ovarian adenocarcinoma SKOV-3 cells overexpressing HER2 receptor. Confocal studies indicated that [223Ra]BaFe–CEPA–trastuzumab was located in peri-nuclear space. High cytotoxicity of the [223Ra]BaFe–CEPA–trastuzumab bioconjugate was confirmed by radiotoxicity studies on SKOV-3 cell monolayers and 3D-spheroids. In addition, the magnetic properties of the radiobioconjugate should allow for its use in guide drug delivery driven by magnetic field gradient.

Synthesis, characterization and studies of BaFe2O4/PMMA nanocomposite

Synthetic nanotechnology has attracted a great deal of attention from researchers for the synthesis of assorted materials at nanoscale dimension. Researchers are more attracted to microwave-assisted route for the synthesis of ferrite nanomaterials due to its simplicity. Barium ferrite (BF) nanomaterials are prepared by two strategies: the barium oxalate and the iron oxalate strategy. Thermal decomposition of barium oxalate precursor and ferrous oxalate precursor has been done using polyvinyl alcohol (PVA) as a fuel. Self-propagating combustion reaction of metal oxalates takes place with fuel, which controls the size of the particle. Solvent casting method is used for the preparation of barium ferrite-dispersed poly(methyl methacrylate) (BF–PMMA) nanocomposite. The structure of the as-prepared samples was carried out by X-ray diffraction (XRD) study and particle morphology of the sample done by scanning electron micrograph (SEM) technique. The presence of barium and iron metals in the sample is confirmed by EDX analysis. Bonding nature of the ferrite is studied by Fourier transform (FT-IR) tool. Thermal and electrical studies of the samples are also undertaken to know the thermal electrical behaviour. UV absorbance study of the said composite is also undertaken.

Synthesis of barium ferrite nanoparticles using rhizome extract of Acorus Calamus: Characterization and its efficacy against different plant phytopathogenic fungi

A green technology for producing barium ferrite (BaFe12O19) nanoparticles (BFNP’s) using Acorus Calamus rhizome extract was realized. To confirm the phase of magnetoplumbite structure without any impurities, the method of powder X-ray diffraction was performed using the Rietveld analysis and the FullProf program with the P63/mmc (No. 194) space group. Unit cell parameters were a = 5.8902(2) Å and c = 23.2103(7) Å. According to Scherrer’s calculations, the average crystallite size was from ∼ 32 to ∼ 35 nm. The results of scanning electron microscopy confirmed that synthesized BFNP’s are tightly packed and have an average grain size of ∼ 70 nm. Raman and IR active modes predicted by group theory are observed at ∼ 175 cm−1 and ∼ 677 cm−1, which corresponds to the presence of a spinel structure and trigonal pyramidal position in barium hexaferrite. It was established that the spontaneous magnetization is ∼ 52 emu/g and coercive force is ∼ 440 mT at room temperature. In vitro studies were performed to evaluate the antifungal activity of BFNP’s against various plant pathogenic fungi, namely: Fusarium oxysporum, Alternaria alternata, Colletotrichum gloeosporioides and Marssonina rosae. The antifungal effect of BFNPs was determined for different phytopathogenic fungi at a multiple dose of 200 mg/L, 300 mg/L, 400 mg/L, 500 mg/L and 600 mg/L. The maximum inhibition of mycelial growth (76.67%) was detected at 600 mg/L against the growth of Fusarium oxysoporum mycelium. The data obtained show that BFNP’s synthesized using Acorus Calamus rhizome extract can be applied as a potential antifungal agent.

Effect of calcination temperature on structural and terahertz characterization of M-type barium ferrite

We present detailed studies on M-type barium ferrite (BaFe12O19, BaM) synthesized by the sol–gel combustion method that is calcined at 1000 °C, 1100 °C, and 1200 °C. In addition to the structural properties, we present the THz optical dielectric constant and conductivity response of this system as a function of calcination temperature. From x-ray diffraction (XRD) studies, a single-phase of the hexagonal structure is established, and the crystallite size (Dhkl) was calculated to be in the range of 26 nm–28.54 nm. The XRD patterns were analyzed to evaluate lattice parameters (a, c, V) and x-ray density (ρx). Home built terahertz time-domain spectroscopy was performed to investigate the complex refractive index (n̂s) of the samples at room temperature in a frequency range of 0.2 THz–1.2 THz. The complex dielectric constant (ε̂s) and conductivity (σ̂s) as a function of calcination temperature were deduced using THz spectroscopy data. The complex dielectric constant and conductivity of BaM were determined for the calcination temperatures of 1000 °C, 1100 °C, and 1200 °C.

Titanium Doped Barium Ferrite—A Case Study

In this paper synthesis of titanium doped barium ferrite (BaTixFe12–xO19) nanoparticles of hexagonal structure by employing sol-gel technique is reported. The composition was varied between x = 0.25 to 0.45. Structural analysis were carried out with the help of techniques such as X-ray diffraction (XRD) for phase identification, scanning electron microscopy (SEM) for morphological studies, to identify the elemental composition energy dispersive spectroscopy (EDX) was performed and Fourier transform infrared spectroscopy (FTIR) for bonding related information. From X-ray analysis it was observed that initially, with increase in Ti concentration there was a decrease in lattice parameters and cell volume. However, at Ti concentration of 0.38, an increase in lattice parameter was observed and has been attributed to electron hopping mechanism. Morphological analysis (SEM) done on the samples reveal that the nanoparticles are spherical in shape. EDX was utilized for elemental analysis of the products. FTIR spectroscopic studies reveal prominent peaks around 470 and 540 cm−1 is attributed to formation of ferrite structure and also indicative that the reaction is complete. The obtained results were discussed in the light of the available literature.

Adsorption of hydrogen sulfide (H2S) by BaFe2O4-activated clay nanocomposite: preparation and evaluation

AbstractIn this study, BaFe2O4–activated clay nanocomposites were successfully synthesized via mechanosynthesis technique for the first time. Structural analysis of the products confirmed the nanoscale formation of nanocomposites. This study focused on adsorption of hydrogen sulfide (H2S) which is a poisonous gas and can be released from sewage sludge. Formation of nanocomposites was verified by scanning electron microscopy (SEM), energy dispersive X-ray (EDS) analysis, Fourier transform infrared (FTIR) and X-ray powder diffraction (XRD). Results showed that different loadings of barium ferrite in the nanocomposite were important for the adsorption rate. Furthermore, adsorption rate of hydrogen sulfide was improved by increasing BaFe2O4- activated clay concentration which was confirmed by statistical results. The highest average of removal efficiency was 92.79±0.90 in the concentration of 300 g.L-1and the loading of 6%. We could recycle BaFe2O4–activated clay nanocomposite 3 times without a significant decrease in activity. Enhanced performance of BaFe2O4–activated clay, compared to other nanocomposites, recommends its application for adsorptive desulfurization.

Combined sulfur and peroxide curing systems applied in cross-linking of rubber magnets

In the present work, barium ferrite in constant loading was dosed to the rubber matrices based on NR, SBR and NBR. Sulfur, peroxide and mixed sulfur and peroxide curing systems were applied for cross-linking of rubber magnetic composites. The application of sulfur or peroxide curing system leads to the formation of different types of linkages between rubber chain segments. As the structure of the formed cross-links plays a significant role in determining the final properties of rubber articles, the main aim of the work was to use the combination of curing systems in order to suppress the disadvantages of both systems and possibly to highlight their benefits. The results showed that composition of curing system has considerable influence on cross-link density of composites, which was subsequently reflected in typical change of physical-mechanical properties and glass transition temperature. The tensile strength was improved with increasing amount of peroxide curing system. The reason can be attributed to the presence of co-agent zinc methacrylate, which exhibits strong adhesion to magnetic filler and thus it contributes to the improvement of compatibility and homogeneity on the interphase filler–rubber. On the hand, there was observed no influence of curing system composition or type of rubber matrix on magnetic characteristics of composites.