Ferrite Particles Research Articles

Effect of La3+ ion doped Co-Zn nano ferrites: Structural, optical, electrical and magnetic properties

Lanthanum substituted Co Zn Fe 2 O 4 fabricated nano ferrite powder was conformed single phase cubic spinal structure from the XRD and particle size conformed by the TEM. Optical and electric properties was studied. VSM was used to investigate magnetic characteristics from room temperature. • Effect of La 3+ ion doped Co-Zn nanoferrites were synthesised through the citrate gel auto-combustion method. • Rietveld refinement was used to analyse XRD data and confirmed the nano-range particles with spinel ferrites. • FE-SEM, EDAX, FTIR, TEM, AFM, FTIR, DC electrical resistivity, dielectric studies, and VSM studies are conducted. Lanthanum ion doped with large percentages of zinc cobalt ferrite (Co 0.1 Zn 0.9 La x Fe 2-x O 4 ) nanoparticles with an ‘x’ range of from 0.000 to 0.030 (with the step of x=0.005) were manufactured through the citrate gel auto-combustion method. The fabricated synthesised powder was analysed to find out the structural characterization from the XRD, FE-SEM, EDAX, TEM, FTIR, and AFM. The average crystallite size was confirmed and nanometer ranges were exposed from the XRD and TEM images, which ranged between 10 nm and 15 nm and the FCC spinel structure. The lattice parameter is found to increase from 8.392 A o to 8.452 A o with the substitution of La 3+ ion, and a monotone diffraction peak (311) shows towards minor angles of degrees (35.33° to 35.13°). The surface area increases from 122.8 to 186.3 m 2 g -1 with the addition of La 3+ ion. From FTIR the bond lenth (ν 1 ) ranges from 512 cm −1 to 530 cm −1 , increasing with doped La 3+ ion content. In the AFM analysis, the surface roughness decreases from 10 nm to 6.5 nm. The prepared samples the results of magnetic, temperature variation of dielectric, and DC resistivity studies were discussed. The dielectric constant reduces dramatically as the substituted lanthanum ion concentration rises with temperature, although it remains stable in the three previously described ranges. DC resistivity, curie temperature, and drift mobility have an inverse relationship with temperature increase. The magnetic properties of hysteresis loops indicate a shift from harder to softer magnetic moments. The Ms and Mr decrease as the lanthanum ion concentration in Co-Zn ferrite increases, from 15.19 emu/g to 9.30 emu/g, and from 3.81 emu/g to 2.33 emu/g and the magnetic moment decreases from 0.6539 to 0.4045. The prepared nano ferrite particles were suited as magnetic adsorbents in the departure of impurities from waste water.

Partial correlation of optical, electrical and magnetic properties of nanosized Zn–Cr–La ferrite particles synthesized by sonochemical method

Zn0.5Cr0.5LaxFe2-xO4 nanoferrites with varied compositions of x = 0.03, 0.06, 0.09, and 0.12 were synthesized using an effective sonochemical reactor. The powders resulting from this synthesis were characterized by X-ray diffraction (XRD) and scanning electron microscopy, energy dispersive X-ray spectroscopy, and their electrical and magnetic properties examined by electrochemical impedance spectroscopy and vibrating sample magnetometer, respectively. The XRD analysis confirms the creation of cubic crystalline structure with the crystallite size from 38 (x = 0.12) to 57 (x = 0.03) nm. The lattice constant of the ferrite nanoparticles is found to decrease with La content. Using XRD patterns, the development of a cubic crystalline structure was revealed. An increase in the amount of La3+ ions in Zn0.5Cr0.5LaxFe2-xO4 nanoferrites could explain the decrease in crystalline size. In Zn0.5Cr0.5LaxFe2-xO4 nanoferrites, impedance investigation revealed the presence of pseudo-capacitance and resistive behavior. The conductivity of Zn0.5Cr0.5LaxFe2-xO4 nanoferrites was also slightly reduced when La3+ ions were added. The soft ferromagnetic behavior of Zn0.5Cr0.5LaxFe2-xO4 nanoferrites was aided by the hysteresis loops. An increase in the La content of Zn0.5Cr0.5LaxFe2-xO4 nanoferrites resulted in a decrease in saturation magnetization and an increase in coercivity.

The microstructures and properties of Fe2O3 and TiO2 co-doped corundum ceramics for solar thermal absorbing materials

Solar thermal absorbing materials are the key components of concentrating solar power. In this study, Fe2O3 and TiO2 co-doped corundum ceramics were prepared by pressureless sintering. The effects of different Fe2O3/TiO2 ratios on the phase composition, microstructure, thermal shock resistance and solar absorptance were investigated via XRD and EPMA testing. The results showed that, with the decrease of Fe2O3/TiO2 ratio, the appropriate amount of FeAlTiO5 would decompose into ferrite particles, which played a bridging role between the corundum grains making the samples have excellent thermal shock resistance. A6 (90% bauxite, 9.5% Fe2O3 and 0.5% TiO2) sintered at 1460 °C had the optimum comprehensive properties, with a bending strength of 154.80 MPa and an absorptance of 89.20% in the spectral range from 0.3 to 2.5 μm. After 30 thermal shock cycles (1000 °C–25 °C, air-cooled), the bending strength of A6 was 222.05 MPa, and the absorptance was 90.40%, which were 43.44% and 1.35% higher than those before thermal shock, respectively. Therefore, it was suitable as an excellent solar thermal absorbing materials.

Magnetic Nanosorbents Based on Bentonite and CoFe2O4 Spinel

New magnetic nanocomposite sorbents were obtained by doping natural bentonite with nanosized CoFe2O4 spinel (10 and 20 wt.%). Nanocrystals of cobalt ferrite were synthesized by a citrate burning method. The structure and physical-chemical properties of the composites were characterized by XRD, XRF, TEM, BET, FTIR and Faraday balance magnetometry. During the formation of nanocomposites, 10–30 nm particles of cobalt ferrite occupied mainly the interparticle space of Fe-aluminosilicate that significantly changed the particle morphology and composite porosity, but at the same time retained the structure of the 2:1 smectite layer. A combination of two functional properties of composites, adsorption and magnetism has been found. The adsorption capacity of magnetic nanosorbents exceeded this parameter for bentonite and spinel. Despite the decrease in the adsorption volume, pore size and specific surface area of the composite material relative to bentonite, the sorption activity of the composite increases by 12%, which indicated the influence of the magnetic component on the sorption process. FTIR data confirmed the mechanism of formaldehyde sorption by the composite sorbent. The production of a magnetic nanosorbent opens up new possibilities for controlling the sorption processes and makes it possible to selectively separate the sorbent from the adsorption medium by the action of a magnetic field.

3D Printing of PLA/Magnetic Ferrite Composites: Effect of Filler Particles on Magnetic Properties of Filament

Three-dimensional printing is one of the most promising areas of additive manufacturing with a constantly growing range of applications. One of the current tasks is the development of new functional materials that would allow the manufacture of objects with defined magnetic, electrical, and other properties. In this work, composite magnetic filaments for 3D printing with tunable magnetic properties were produced from polylactic acid thermoplastic polymer with the addition of magnetic ferrite particles of different size and chemical composition. The used magnetic particles were cobalt ferrite CoFe2O4 nanoparticles, a mixture of CoFe2O4 and zinc-substituted cobalt ferrite Zn0.3Co0.7Fe2O4 nanoparticles (~20 nm), and barium hexaferrite BaFe12O19 microparticles (<40 µm). The maximum coercivity field HC = 1.6 ± 0.1 kOe was found for the filament sample with the inclusion of 5 wt.% barium hexaferrite microparticles, and the minimum HC was for a filament with a mixture of cobalt and zinc–cobalt spinel ferrites. Capabilities of the FDM 3D printing method to produce parts having simple (ring) and complex geometric shapes (honeycomb structures) with the magnetic composite filament were demonstrated.

Hydrolyzed Arabic gum-grafted-polyacrylonitrile@ zinc ferrite nanocomposite as an efficient biocatalyst for the synthesis of pyranopyrazoles derivatives

A catalytic methodology for the effective synthesis of pyrazolopyrazole derivatives using a combination of hydrolyzed Arabic gum-g-polyacrylonitrile/ZnFe2O4 (Hyd AG-g-PAN/ZnFe2O4) catalyst, malononitrile, and aromatic aldehyde, hydrazine hydrate, and ethyl acetoacetate is described. This protocol relies on the use of environment-friendly heterogeneous catalyst based on zinc ferrite magnetic particles in combination with Arabic gum (AG) as the backbone, N, N methylene bisacrylamide (MBA) as a crosslinking agent, ammonium persulfate (APS) as an initiator, and alkaline solution for hydrolyzation. This bio-based catalyst with a soft three-dimensional cross-linked framework contains distinct acidic and basic sites and could be applied as a powerful catalyst for the one-pot synthesis of pyranopyrazoles derivatives. Using an external magnet, the superparamagnetic nanocomposite could be easily separated. Furthermore, the catalyst can well be utilized at least six times in subsequent reaction cycles before losing its activity. FT-IR, EDX, TGA, FESEM, VSM, and XRD methods were used to characterize the produced catalyst. Taking 0.01 g of catalyst at 80 °C in a green solvent of water/ethanol, the greatest output of dihydropyrano [2,3-c] pyrazole was 96% in 15 min. A simple technique, short reaction time, high yield, and the catalyst's reusability and stability are just a few of the study's advantages.

A Comparative Analysis of Structural, Optical and Electrical Properties of Polyaniline/Ferrite (Co, Ni, Cu, Zn) Composites

Considering the magnificent optical and electric properties of polyaniline (PANI), in this study, PANI, PANI/MFe2O4(M=Co, Ni, Cu, and Zn) composites were studied. Polyaniline and their composites with ferrites were prepared via chemical oxidation method. Ferrites were synthesized through co-precipitation method. Structural properties were investigated using X-ray diffraction (XRD) and Fourier Transform Infrared spectroscopy (FTIR) respectively. Their results reveal the semi-crystalline nature of synthesized materials with the crystallite size in the range of 21.78 to 37.20 nm. Scanning electron microscope (SEM) analysis also confirmed the formation of all the nano-sized synthesized composites. In the UV–vis analysis, the optical band gap of composites is reducing upto 1.01 eV for PANI-cobalt ferrite as compared to pure PANI (2.38 eV). The inclusions of ferrites particles have caused an enhancement in electrical conductivity of pure PANI. It is 3*10−4 S cm−1 at high frequency for PANI and increased upto 5*10−4 S cm−1 for PANI-Zinc Ferrite composite. The investigated data shows the enhanced optical and electric properties of PANI/ferrites composites to a great extent, making them promising materials for different applications.

Influence of Cementite Precipitation on Work Hardening Behavior in Ultrafine Grain Steels Rolled at Room and Cryogenic Temperatures

The work hardening behavior of α + θ UFG steel related to α + θ two phase microstructure is more complicated than that of single-phase materials. Very few studies have been conducted on the work hardening of α + θ UFG steels. Therefore, it is necessary to study the correlation between the work hardening and α + θ microstructure. In this study, the work hardening behavior of low-carbon ultrafine grain (UFG) steels with different grain size of ferrite and cementite particles, fabricated by rolling and annealing process, was studied. The α grain size was decreased to 132 ± 11 and 200 ± 19 nm in specimens cryorolled and annealed at 450 and 550 °C, which were smaller than that in specimen cold-rolled and annealed at 550 °C. However, the specimen cryorolled and annealed at 550 °C had a tensile strength of 740.3 MPa, which was lower than that in the other specimens. Results indicate that the work hardening is affected by ferrite and cementite in the UFG steels. The relatively coarse ferrite phase and the large number of fine intragranular cementite particles contribute to better work hardening. The intragranular cementite particles play a significant role in the improvement of work hardening, because the geometrically necessary dislocations are apt to form and store around intragranular cementite particles, while the intergranular cementite particles result in the decreased dislocation accumulation ability of ferrite and impair the strength of grain boundaries and work hardening of ferrite + cementite ultrafine grain steels.

Suspension rheology of polyaniline coated manganese ferrite particles under electric/magnetic fields

Manganese ferrite (MnFe2O4) nanoparticles initially fabricated using a solvothermal process were coated with conducting polyaniline (PANI) to produce core/shell-structured MnFe2O4/PANI nanoparticles. An electro/magnetorheological (E/MR) fluid was prepared by suspending MnFe2O4/PANI particles in silicone oil, and the rheological properties under either electric or magnetic fields were investigated. Scanning electron microscope and transmission electron microscope provided the particle morphology and size information. X-ray diffraction and Fourier transform infrared spectroscopy were used to analyze the crystal structure and chemical composition of the particles. Chain formation in E/MR fluids under electric or magnetic fields was observed by optical microscopy, and the rheological properties were evaluated using a rheometer. Steady shear and dynamic oscillatory tests were conducted to confirm the effective E/MR characteristics while varying the electric/magnetic field strength. The dielectric properties of the particles measured using an LCR meter were analyzed based on the Cole-Cole model. The E/MR fluids composed of MnFe2O4/PANI showed a reversible and fast electro/magnetic response.

Antibacterial Activities of Ni Substituted Ferrite Particles for Biological Applications

In this research work Mg0.45Mn0.55-xNixFe2O4 ferrite particles of varying compositions (x=0.05, x=0.15, x=0.25, x=0.45 and x=0.55) were synthesized using cost effectual co-precipitation route. The synthesized ferrite particles were characterized by collection of techniques. XRD analysis confirmed the formation of cubic spinel structure of the ferrite particles. SEM and AFM analyses illustrated the morphology and size distribution of obtained ferrite particles. FT-IR study exposed that the absence of any additional peak related to second phase. VSM results indicated magnetic analyses such as saturation magnetization (MS), Coercivity (HC) and Remanence (Mr) of ferrite particles. The major objective of the present investigation is to synthesize MgMnNiFe2O4 ferrite particles on cotton fabrics in order to obtain finished fabrics; it is very significant in biological applications. The antibacterial activities of the ferrite particles coated cotton fabrics were tested against selected Gram positive and Gram negative bacteria which showed tremendous results via formation of inhibition zones. The fabricated ferrite particles on cotton fabrics showed great durability evidenced by their antibacterial activities even after 20 washing cycles. Hence, the functionalized cotton fabrics could be used as potential antibacterial agent.

Synthesis of Substituted Barium Ferrites and Hexaferrites and Their Electrochemical Characterization

Magnetic nanoparticle has been an attractive area of research in view of their unique physical and chemical properties. [1] In the field of electrochemistry, particularly electroanalysis, they are extensively used as functional materials due to their high surface area, mass transport, catalytic effect, and control over the local environment. Barium based ferrites have emerged as attractive materials of interest due to their interesting physical, chemical, magnetic and electrical properties. [2] Hexaferrite and ferrites such as barium ferrite are very important group of magnetic oxides and these are used in different technologies including sensors because of their specific properties such as low cost, corrosion resistance chemical stability and large magneto crystalline anisotropy. [3] However, the investigation of the effect by various other elements on the structure of hexaferrite and ferrite particles and its electrochemical properties remains the subject of popular research. In this work, mixed metallic oxides hexaferrite and ferrite were synthesized by sol–gel combustion route using glycerin as an adjuvant. [4] Their structure was confirmed by means of X-ray powder diffraction. Scanning electron microscopy were used to investigate the morphology of the sample and the vibrations of the functional groups were determined by Raman and IR-ATR spectroscopy. The electrochemical behavior of substituted hexaferrite and ferrite were determined by cyclic voltammetry using an Ag/AgCl electrode, platinum wire and a glass carbon electrode (GCE), as reference electrode, counter electrode and working electrode, respectively. The GCE was modified with mixed metal oxides obtained to analyze their electrochemical behavior.Bibliographic Xueli X, Wei S 2019 Materials Technology, 1-5Kefeni, K.K.; Msagati, T.A.; Mamba, B.B. 2017, Sci. Eng. B. 215, 37–55Valenzuela R, Magnetic Ceramics, Chemistry of Solid State Materials 4 serie. Cambridge (Great Britain): Cambridge University Press, 1994, p. 50Sandra F. Basante-Delgado, Dalliver González-Vidal, Jimmy A. MoralesMorales, William A. Aperador-Chaparro, Jairo A. Gómez-Cuaspud, 2020 Phys.: Conf. Ser. 1541 012013

Cobalt Ferrite Particles Produced by Sol-Gel Autocombustion and Embedded in Polysilane: An Innovative Route to Magnetically-Induced Fluorescence Composites.

Fluorescence detection is currently one of the commonly used techniques worldwide. Through this work, the preparation and optical properties of an interesting composite material are discussed. It is shown that encapsulating cobalt spinel ferrite (CoFe2O4), obtained by the sol-gel autocombustion method, into poly[diphenyl-co-methyl(H)]silane matrix leads to fluoromagnetic particles (PSCo) with intriguing optical properties. Transmission electron microscopy, combined with energy-dispersive X-ray analysis, showed 500 nm large spherical structures containing a core (around 400 nm in diameter) composed of magnetic ferrite particles, surrounded by a thin layer of semiconductive fluorescent polymer. The as-obtained material exhibited ferrimagnetic properties. The FTIR spectrum confirmed that the Si-H functionality of the polysilane was preserved. UV spectroscopy combined with molecular modeling studies indicated that the magnetic core had a strong influence on the intramolecular electron transitions characteristic of the σ-conjugated polysilane. Further analysis by steady-state fluorescence spectroscopy revealed that the internal magnetic field strongly enhances the polysilane emission. This property will be further investigated in the future in order to develop new detection devices.

Hydrothermally Synthesized Magnesium doped Zinc Ferrite Nanoparticles: An extensive study on structural, optical, magnetic, and dielectric properties

Magnesium-doped Zinc ferrite (MgxZn1-xFe2O4) nanoparticles with an average size of 10.1-5.89 nm were prepared by low-temperature hydrothermal method using NaBH4 as the reducing agent. The structural, microstructural, optical, magnetic, and dielectric properties of these nanoparticles were extensively studied. Rietveld refinement profile confirmed the formation of mixed spinel structures with cubic lattices (space group Fd3m). A complete microstructural study revealed the polycrystallinity nature of the powder along with the formation of nano-sized particles. The Raman spectral analysis showed broadening, merging, and shifting of Raman peaks with an increase in dopant concentration. The X-ray photoelectron studies exhibited the presence of Fe2+ and Fe3+ ions corroborating the results obtained from Rietveld analysis. The optical studies elucidate a reasonably high absorbance in the UV region with a bandgap of 2.05-1.92 eV, which showed a minimum value of 1.92 eV for 50% of Mg doping. These nano-sized ferrite particles were observed to be superparamagnetic due to their small size and gradually developed to a ferromagnetic state, but with a low value of magnetization, coercivity, and remanent magnetization. These nano ferrites exhibiting high dielectric constant, high impedance, and significantly low loss may have potential applications in communication devices.

Hardening of Cobalt Ferrite Nanoparticles by Local Crystal Strain Release: Implications for Rare Earth Free Magnets.

In this work, we demonstrate that the reduction of the local internal stress by a low-temperature solvent-mediated thermal treatment is an effective post-treatment tool for magnetic hardening of chemically synthesized nanoparticles. As a case study, we used nonstoichiometric cobalt ferrite particles of an average size of 32(8) nm synthesized by thermal decomposition, which were further subjected to solvent-mediated annealing at variable temperatures between 150 and 320 °C in an inert atmosphere. The postsynthesis treatment produces a 50% increase of the coercive field, without affecting neither the remanence ratio nor the spontaneous magnetization. As a consequence, the energy product and the magnetic energy storage capability, key features for applications as permanent magnets and magnetic hyperthermia, can be increased by ca. 70%. A deep structural, morphological, chemical, and magnetic characterization reveals that the mechanism governing the coercive field improvement is the reduction of the concomitant internal stresses induced by the low-temperature annealing postsynthesis treatment. Furthermore, we show that the medium where the mild annealing process occurs is essential to control the final properties of the nanoparticles because the classical annealing procedure (T > 350 °C) performed on a dried powder does not allow the release of the lattice stress, leading to the reduction of the initial coercive field. The strategy here proposed, therefore, constitutes a method to improve the magnetic properties of nanoparticles, which can be particularly appealing for those materials, as is the case of cobalt ferrite, currently investigated as building blocks for the development of rare-earth free permanent magnets.

Dielectric, electrical, magnetic, and mechanical properties of Ni-Al ferrite/PANI composite films

ABSTRACT The Ni-Al ferrite nanoparticles are synthesized by the flash auto-combustion method, and PANI is synthesized by the situ-chemical oxidative polymerization method. NiAl-ferrite/PANI/ x (PANI) Nanocomposite Films (x = 0.6 and 0.8) were prepared using a solution casting process. The X-ray results of the NiAlxFe2-xO4/PANI composite manifest that the Ni-Al ferrite fully interacted with PANI molecules and the Ni-Al ferrite particles are embedded in the PANI chains from TEM and SEM images. The dielectric parameters ϵ′, ϵ″ and tan δ decreased with the increase in the frequency of the applied field. The modulus M″ spectra of the investigated samples show two relaxation peaks in two frequency regions. In Cole–Cole plot of M′ versus M″, a semicircular trend is observed, i.e. a non-Debye criterion. The presence of PANI in the NiAl0.6Fe1.4O4/PANI composite films reduces the magnetic properties of the composite samples leading to the decrease of saturation magnetization and remanence magnetization.

Dynamic viscosity of strontium ferrite–nylon composite below the melting temperature

Hard-magnetic 3D-printer filaments made of 40 wt. % SrO(Fe2O3)6/PA12 composites made using a twin-screw extruder are being studied to be used for Magnetic Field Assisted Additive Manufacturing (MFAAM). The time dependence of the magnetic properties above the softening temperature of the PA12 matrix but below the melting point was studied using a biaxial Vibrating Sample Magnetometer (VSM). Specifically, the rotation of the magnetic particles in the softened polymer matrix after the application of a rotation field was extracted from the time dependent biaxial VSM signals. Above 132 °C, the strontium ferrite particles can rotate in the nylon matrix. The measured time constant decreases with temperature and magnitude of the rotation field. Model calculations indicate that, for 40 wt. % SrO(Fe2O3)6/PA12 at rotation fields of 500 Oe, the effect of the demagnetizing field on the angle between the magnetic moment and the particle’s easy axis is negligible, allowing one to determine the dynamic “melt” viscosity from the measured transients. The dynamic viscosity decreases from 2 × 105 Pa s at 132 °C to 3.1 × 104 Pa s at 175 °C with a sharp kink observed near 140 °C that correlates with a relaxation from the α′c phase for PA12 observed by others. A yield shear stress was observed for small rotation fields at low temperatures resulting in non-perfect alignment of the magnetic particles. The implications of the measurement results for MFAAM are discussed.

Adsorption of acid fuchsine dye from wastewater by Mg-ferrite particles.

Adsorption is a widely applied waste water treatment technology, especially for removing micro-pollutants and dyes of industrial effluents. Over the past decade, adsorbing metal oxide micron- and nano-particles have been successfully developed and investigated as adsorbents. In the present research, Mg-ferrite adsorbent particles were synthesized and their properties were fully determined. The pore volume is 0.139cm3/g. The BET analysis reveals a surface area of 94.4m2/g. The porosity is of meso- and microporous nature. The adsorbent was used to adsorb acid fuchsine, an important industrial dye. The equilibrium adsorption capacity was 796.4mg/g, with an adsorption yield of 78.7-82.0%. The adsorption kinetics can be adequately fitted by a pseudo-second-order model. The isotherms of both Langmuir and Freundlich are applicable. The stability, recovery and reuse of the ferrite particles were proven in multi-cycle experiments, and the adsorption activity decreased by less than 3% between the first and fifth cycle. Experimental and fitting results were finally used to design a batch adsorber to remove a given concentration of acid fuchsine from different volumes of wastewater.

Hydrogen reduction of low-grade banded iron ore

The current study investigates hydrogen reduction of low-grade iron ore (∼37 % Fe) containing dispersed bands of hematite and jasper/quartzite phases. Gaseous hydrogen reduction is carried out at isothermal conditions in a custom-made tubular furnace, followed by magnetic separation. The reduction temperature (300–600 °C), time (30–90 min), particle size (0.5–3.3 mm), and hydrogen flow rate (0.5–1.5 LPM) were optimized by statistical design of experiments to maximize the saturation magnetization, degree of reduction and metallization. Complete reduction of hematite was achieved in 2 h at 600 °C; however, the separation of quartz from reduced ferrite was inefficient evidenced by the lower saturation magnetization. The association of impurities with hematite does not affect the reduction rate; however, the trapped quartz particles in the reduced phases deteriorate the magnetic separation efficiency. Temperature and time synergize the reduction rate, improving reduction and metallization degree; meanwhile, flow rate and particle size have minimal effect. Reduction below 450 °C restricted the reduction to magnetite, and the optimal conditions; 600 °C, 60 min, 0.5 LPM H2, and 3.3 × 2 mm particle size yielded ferrite concentrate possessing saturation magnetization of 134.6 emu/g (68 % FeM) with 97.9 % DOR, 88.8 % DOM and 47.3 % yield. The reduction of hematite results in generation of micro cracks and porous morphology of the ferrite. Iron oxide reduction follows the Fe2O3 → Fe3O4 → Fe, evidenced by the absence of wustite (FeO) or fayalite (FeO.SiO2) phases in the product. The ferrite particles form a fused and porous layer trapping the silica particles.

Soft Magneto‐Responsive Shape Memory Foam Composite Actuators

AbstractSoft magnetic composites are exceptional because they can be controlled remotely, move quickly, conform to hard things, and interact with people safely. However, even with all these features, magnetic elastomers suffer a lack of stability due to the high softness of the elastomer. This issue affects their controllability and repeatability. This article introduces a novel conceptual design of magneto‐responsive shape memory polyurethane (SMP) foam composites with high stability and reversibility. The fabrication technique is based on the silicone resins filled with strontium ferrite magnetic particles and a thin SMP foam placed onto one side. Material properties, room‐temperature shape recovery features, and magnetization conditions necessary for the process are determined by experimental studies of composite actuators. As a result, a workable, light, stable, soft composite gripper with programmable magnetic patterns is created, which can carry out activities like grabbing, holding, and moving objects in horizontal and vertical directions when a low magnetic field is applied. The SMP foam increases the contact surface and decreases the weight by up to three times providing better stability compared to the magnetic elastomer without SMP foam. The shape‐recoverable gripper with a small contract area can lift objects eight times heavier than its weight.

Spinel ferrite nanomaterials - MgFe2O4 - Synthesis by appropriate microwave solution combustion (Msc) method of visible light–responsive photocatalyst for Rb21 dye degradation

Ferrite’s spinel has acquired appeal for its use in biomedical, pharmaceuticals, electrical devices, photocatalyst, and other fields. Spinel may also be manufactured using the Microwave Solution Combustion (MSC) process, which is a viable alternative to sol–gel, co-precipitation, hydrothermal, and Hammer's methods since it is rapid, energy-efficient, and requires lesser equipment. The MSC technique provides insight into the impact of its many factors. Microwave irradiation is utilized in this method to retain precursors in an excited state and make them highly reactive. This technique is usually carried out using a Raga's scientific microwave reactor with a frequency of 2.45 GHz, T = 100°C. Metal nitrates (precursers) and Urea are the most often utilized preparation for nanomaterials. Because of its high-temperature range or propellant combustion requirements, urea is the most used fuel. To accomplish a quicker and better yield product, many factors such as fuel to oxidizer ratio, irradiation period, microwave power, temperature and pressure may be tuned. This procedure does not require any additional calcination; however, it does necessitate numerous washing steps to purify the final result. The 4000–400 cm−1 peaks were examined in the composition characterization of spinel ferrites using FTIR findings. The focus of the research was to find a MgFe2O4 spinel with a Magnesium A-site in Ferrite particles. This study is to explore catalyst behaviour in sessions of structural, compositional, crystallinity, and magnetic stability with neodymium magnets used for the separation of RB21 dye from synthetic wastewater. To check the reusability at 20 mg catalyst dosage at 20 mg/L dye concentration which gives 4 runs efficiency 90% − 66% observed.