Fe2O4 Nanopowders Research Articles

Electrospun polyacrylonitrile reinforced greenly synthesized iron oxide nanocomposite fibers sheet for remediation of azithromycin from water

The contamination of water bodies by pharmaceuticals, such as azithromycin (AZM), poses significant environmental concerns. In this study, electrospun polyacrylonitrile (PAN) reinforced with greenly synthesized iron oxide nanocomposite (PAN@Fe2O3) fibers sheet was prepared for the removal of azithromycin from water. The Fe2O3 nanopowder was synthesized via a facile and eco-friendly method using natural extracts as reducing and stabilizing agents. Then synthesized nanoparticles powder was incorporated in PAN surface by using simple electrospinning method. The morphology, structure, and composition of the nanocomposite fibers were characterized using XRD, FTIR, BET, FESEM and HRTEM analytical techniques. Utilising a molecular dynamics (MD) method, the mechanical characteristics of the PAN@Fe2O3 nanocomposite were theoretically examined. Batch adsorption experiments were conducted to evaluate the adsorption capacity of the nanocomposite fibers for AZM removal from aqueous solutions. The effects of various parameters such as dose, pH, contact time and initial AZM concentration on the adsorption process were investigated. The results demonstrated excellent adsorption performance, with a maximum adsorption capacity of 73.49 mg/g at pH=7. Furthermore, the adsorption kinetics and isotherms were analysed to understand the adsorption mechanism and equilibrium behaviour. Furthermore, for a minimum of four adsorption-desorption cycles, the adsorbent may be cycled and regenerate in succession.

Cracking of Heavy Oil in Supercritical Water in the Presence of Iron Oxide Nanopowder: Asphaltene Transformations and Process Kinetics

The products of catalytic cracking of heavy crude oil from the Ashalchinskoye oil field (the Almetyevsk district of the Republic of Tatarstan, Russia) were characterized. The effects of a Fe2O3 nanopowder catalyst and the presence of supercritical water (SCW) on the composition and structure of these cracking products were investigated. Cracking over 0.01 wt % Fe2O3 nanopowder in a SCW environment was found to enhance the yield of distillates by more than 34 wt % and to reduce the content of resinous asphaltene materials by a factor of 2.1 compared to the initial crude oil. It was further shown that Fe2O3-nanopowder-catalyzed cracking produces coke-like asphaltenes with a low H/C atomic ratio (no higher than 0.75). Reaction rate constants were evaluated for the thermal and catalytic cracking of the heavy oil from the Ashalchinskoye field.

Fe2O3 Synthesized by Sol-Gel Method for Energy Storage Applications

Fe2O3 nanopowders were synthesized by sol-gel method from the iron source material Fe(NO3)3.9H2O and citric acid C6H8O7.H2O without any refined process. The structure and size of the synthesized materials were determined by X-ray diffraction and scanning electron microscopy. The obtained product is α-Fe2O3 with different shapes and sizes depending on the preparation conditions. α-Fe2O3 was applied as anode of iron-air battery. The cyclic voltammetry measurements showed that the size and morphology of Fe2O3 particles affect their electrochemical characteristics. Using K2S as an electrolyte additive improved the electrochemical properties of Fe2O3/AB electrodes as evidenced by increased redox reaction rate of iron, increased capacity of Fe2O3/AB electrode and reduced H2 evolution.

Structural, dielectric, and magnetic properties characterization of sol–gel synthesized CaxZn(0.90-x)Ni0.10Fe2O4 nanopowder and its application as flexible microwave substrate with polarization-insensitive SNG metamaterial

In this work, CaxZn(0.90-x)Ni0.10Fe2O4 nanopowder-based new flexible microwave substrates are prepared using the sol–gel method for metamaterial applications. Three different x values are chosen as x = 25, 50, 75 and termed as Ca25, Ca50, and Ca75 respectively. The structural and morphology of synthesized materials are investigated with XRD and FESEM analysis. The dielectric properties were also determined and the obtained values for dielectric constant (εr) and loss tangents (Tδ) are ranges from 3.25 to 4.25 for εr and 0.0025 to 0.0065 for Tδ for Ca25, Ca50, and Ca75 respectively. In addition, the magnetic permeability μr and magnetic loss tangent (Tδm) values are estimated from the scattering parameters S11 and S21 obtained by using Agilent module 85071E, and the achieved values of μr and Tδm are ranges from 0.875 to 1.00 and 0.0035 to 0.0075 respectively. Later, the proposed metamaterial unit cell consists of a square split ring resonator (SSRR) and a circular SRR (CSRR) loaded with a plus shape is designed and fabricated on the proposed flexible substrates obtained from the synthesized CaxZn(0.90-x)Ni0.10Fe2O4 nanopowders to validate their application as metamaterials. The novelty of the proposed work is found in the unit cell being polarization-insensitive and having a multiband, low electrical dimension that improves the EMR, single-negative characteristics with high flexibility and lightweight and suitable for C, X, and Ku bands of microwave regime.

Facile synthesis of Zn0.5Ni0.5Fe2O4/carbon nanocomposite for hyperthermia and drug delivery applications

Zn0.5Ni0.5Fe2O4 nanopowders as heating agents could be used for hyperthermia due to their magnetic characteristics. However, due to the lack of suitable surface properties, magnetic ferrites do not have proper drug absorption capacity and sometimes show cytotoxicity. These concerns limit their application in medical use. A simple one-step method to synthesize the Zn0.5Ni0.5Fe2O4/carbon nanocomposite is an effective strategy to solve these issues. Metal salts and citric acids were dissolved in water and heated till combustion was taken place. In this procedure, the synthesis of magnetic material and carbonization occurred simultaneously. The results showed that Zn0.5Ni0.5Fe2O4 nanoparticles were uniformly engulfed into carbon produced by a self-propagating combustion method. Magnetic properties of Zn0.5Ni0.5Fe2O4/C nanocomposite showed the ferrimagnetic characteristics with the saturation magnetization of about 54 emu/g. The specific loss power (SLP) values of the samples heat-treated at 100 and 400 °C were 14 and 42 W/g, respectively. The produced samples were loaded with cephalexin. The cephalexin-loaded Zn0.5Ni0.5Fe2O4/C nanocomposite demonstrated controlled drug release, efficient antibacterial characteristics against Staphylococcus aureus, and Escherichia coli, and significant hyperthermia ability. Therefore, the synthesized nanocomposites might open up a way for efficient hyperthermia and drug release applications and have a prospective use in medical science.

Microstructure and Magnetic Properties of Grain Boundary Insulated Fe/Mn0.5Zn0.5Fe2O4 Soft Magnetic Composites.

Mn0.5Zn0.5Fe2O4 nano-powder was coated on Fe microparticles by mechanical ball milling combined with high-temperature annealing. The effects of milling time on the particle size, phase structure and magnetic properties of core–shell powder were studied. Scanning electron microscopy (SEM), energy-dispersive spectroscopy and X-ray diffraction showed that the surface of the milled composite powder was composed of thin layers of uniform Mn0.5Zn0.5Fe2O4 insulating powder. SEM also revealed a cell structure of Fe particles, indicating that the Fe particles were well separated and isolated by the thin Mn0.5Zn0.5Fe2O4 layers. Then, Fe/Mn0.5Zn0.5Fe2O4 soft magnetic composites were prepared by spark plasma sintering. The amplitude permeability of Fe/Mn0.5Zn0.5Fe2O4 SMCs in the Fe/Mn0.5Zn0.5Fe2O4 soft magnetic composites was stable. The resistivity decreased with the increase in sintering temperature. The loss of the composite core was obviously less than that of the iron powder core. Hence, the preparation method of Mn0.5Zn0.5Fe2O4 insulating iron powder is promising for reducing core loss and improving the magnetic properties of soft magnetic composites.

Highly Efficient Photocatalyst Fabricated from the Chemical Recycling of Iron Waste and Natural Zeolite for Super Dye Degradation.

In this paper, Fe2O3 and Fe2O3-zeolite nanopowders are prepared by chemical precipitation utilizing the rusted iron waste and natural zeolite. In addition to the nanomorphologies; the chemical composition, structural parameters, and optical properties are examined using many techniques. The Fe2O3-zeolite photocatalyst showed smaller sizes and higher light absorption in visible light than Fe2O3. Both Fe2O3 and Fe2O3-zeolite are used as photocatalysts for methylene blue (MB) photodegradation under solar light. The effects of the contact time, starting MB concentration, Fe2O3-zeolite dose, and pH value on photocatalytic performance are investigated. The full photocatalytic degradation of MB dye (10 mg/L) is achieved using 75 mg of Fe2O3-zeolite under visible light after 30 s, which, to the best of our knowledge, is the highest performance yet for Fe2O3-based photocatalysts. This photocatalyst has also shown remarkable stability and recyclability. The kinetics and mechanisms of the photocatalytic process are studied. Therefore, the current work can be applied industrially as a cost-effective method for eliminating the harmful MB dye from wastewater and recycling the rusted iron wires.

Recycling Rusty Iron with Natural Zeolite Heulandite to Create a Unique Nanocatalyst for Green Hydrogen Production.

Corrosion-induced iron rust causes severe danger, pollution, and economic problems. In this work, nanopowders of Fe2O3 and Fe2O3/zeolite are synthesized for the first time using rusted iron waste and natural zeolite heulandite by chemical precipitation. The chemical composition, nanomorphologies, structural parameters, and optical behaviors are investigated using different techniques. The Fe2O3/zeolite nanocomposite showed smaller sizes and greater light absorption capability in visible light than Fe2O3 nanopowder. The XRD pattern shows crystalline hematite (α-Fe2O3) with a rhombohedral structure. The crystallite sizes for the plane (104) of the Fe2O3 and Fe2O3/zeolite are 64.84 and 56.53 nm, respectively. The Fe2O3 and Fe2O3/zeolite have indirect bandgap values of 1.87 and 1.91 eV and direct bandgap values of 2.04 and 2.07 eV, respectively. Fe2O3 and Fe2O3/zeolite nanophotocatalysts are used for solar photoelectrochemical (PEC) hydrogen production. The Fe2O3/zeolite exhibits a PEC catalytic hydrogen production rate of 154.45 mmol/g.h @ 1 V in 0.9 M KOH solution, which is the highest value yet for Fe2O3-based photocatalysts. The photocurrent density of Fe2O3/zeolite is almost two times that of Fe2O3 catalyst, and the IPCE (incident photon-to-current conversion efficiency) reached ~27.34%@307 nm and 1 V. The electrochemical surface area (ECSA) values for Fe2O3 and Fe2O3/zeolite photocatalysts were 7.414 and 21.236 m2/g, respectively. The rate of hydrogen production for Fe2O3/zeolite was 154.44 mmol h−1/g. This nanophotocatalyst has a very low PEC corrosion rate of 7.6 pm/year; it can retain ~97% of its initial performance. Therefore, the present research can be applied industrially as a cost-effective technique to address two issues at once by producing solar hydrogen fuel and recycling the rusted iron wires.

Magnetic, dielectric and structural properties of CoxZn(0.90-x)Al0.10Fe2O4 synthesized by sol–gel method with application as flexible microwave substrates for microstrip patch antenna

In this study, novel flexible microwave substrates based on CoxZn(0.90-x)Al0.10Fe2O4 nanopowder having an average grain size of 20 nm–26 nm were prepared using the sol–gel synthesis technique for microstrip patch antenna applications. At first there are three different molecular composition were chosen having the chemical formula of CoxZn(0.90-x)Al0.10Fe2O4 and specified as Co20, Co40 and Co60 for x = 20%, x = 40% and x = 60% respectively. Then the synthesized ferrites materials were characterized with XRD, FESEM, and VSM analysis, and single-phase spinel with high crystallinity were revealed. Besides, the dielectric and magnetic properties of the proposed Co–Zn ferrites samples were investigated for the affirmations of microwave applications. The values of dielectric constant εr and loss tangent (Tδ) are determined using dielectric assessment kit, and the obtained values are ranges from 3.5 to 4.5 for εr and 0.002 to 0.006 for Tδ for Co20, Co40, and Co60 respectively. Also, the magnetic permeability μr and magnetic loss tangent (Tδm) values are determined to form the predetermined scattering parameters S11 and S21 obtained from rectangular substrate pellets and the obtained values of μr and Tδm are ranges from 0.90 to 1.00 and 0.003 to 0.007 respectively. Finally, a modified diamond-shaped microstrip patch antenna is designed and fabricated on the proposed flexible substrates obtained from the synthesized Co–Zn ferrites nanopowders by mixing with PVA binder to validate their application in the S-band of microwave regime. The finite element method based computer simulation technology software is used to design the proposed microstrip patch antenna; furthermore, the simulated prototype is fabricated, and their reflections coefficients are measured for verification. The simulated and measured result of the proposed flexible antennas exhibits a maximum of 3 GHz bandwidth in between 2.5 and 5.5 GHz. Thus, the proposed materials offers tunable dielectric and magnetic properties with soft magnetic behaviors and easy to use where arbitrarily electromagnetic values are required. Moreover, these materilas also can be played significant role in flexible microwave field as low cost flexible substrates for compact flexible antennas, metamaterials, absorbers, and sensors applications etc.

Fabrication and characterization of GdxFe2O3(100-x) /PVA (x=0, 5, 10, 20) composite films for radiation shielding

Purpose of this study is to investigate effect of gadolinium (Gd) content of GdxFe2O3(100-x), (x = 0, 5, 10, 20) composite system on structural, thermal, optical and radiation protection of poly (vinyl alchool) PVA based nanocomposite film. In this study, Gd doped Fe2O3 nanopowders (with Gd = 0, 5, 10 and 20) were synthesized by spray pyrolysis method. The characterization of these powders have been obtained by using X-ray diffractometer (XRD), scanning electron microscopy (SEM), and Uv–vis spectrometer. After then, GdxFe2O3(100-x)/PVA (x = 0, 5, 10, 20) polymer composite systems were prepared by solution casting technique. The structural, thermal and optical properties of obtained polymer composites have been examined. The irradiation properties of 6 MeV energized X-ray via cLINAC to obtain radiation shielding performance of these different percentage (0, 5, 10, and 20%) Gd doped Fe2O3 PVA thin films were also investigated. By using obtained results, the Linear Attenuation Coefficient (LAC), Half Value Layer (HVL), Tenth Value Layer (TVL), Mass Attenuation Coefficient (MAC). Also, theoretically Zeff value have been calculated. According to all obtained results, it has been seen that the different percentages (0, 5, 10, and 20%) Gd doped Fe2O3 PVA thin films can be used as radiation shielding material.

Improvement of magnetoelectric coupling effect in Ba0.8Sr0.2TiO3-Co0.5Cu0.5Fe2O4 multiferroic fluids by tuning the composition

Ba0.8Sr0.2TiO3 (BST) and Cu0.5Co0.5Fe2O4 (CCFO) nanopowders were prepared by hydrothermal method and chemical coprecipitation, respectively. Barium strontium titanate nanopowder–nano mixed oxides containing copper, cobalt, and iron (BST-CCFO) multiferroic fluids with different mass ratios (mBST/mCCFO = 1:2, 1:1, and 2:1) were prepared by using dimethyl silicone oil and silane coupling agent. Effect of mass ratio on the magnetoelectric performance was comparatively investigated. X-ray diffraction (XRD) showed that the BST and CCFO powders had no secondary phases, which are tetragonal perovskite structure and cubic spinel structure, respectively. Scanning electron microscopy (SEM) showed that the average grain size of BST and CCFO was 26.34 nm and 26.82 nm, respectively. The agglomeration of BST nanopowder was serious. Under the external magnetic field, the BST-CCFO multiferroic fluid will form a chain structure due to the directional movement of magnetic particles, thus enhancing the dielectric properties and ferroelectric properties of multiferroic fluid. The chain structure under the action of magnetic field will change the motion of ferroelectric particles, so that the magnetoelectric coupling effect of multiferroic fluid is significantly enhanced, which is much higher than that of the same type of magnetoelectric composite ceramics. This study is expected to provide a new way to improve the magnetoelectric coupling effect of multiferroic materials.

X-band radar-absorbing structures based on MWCNTs/NiZn ferrite nanocomposites

ABSTRACT Microwave absorbers present a wide range of applications in radar and telecommunications. To improve the microwave absorption characteristics of radar-absorbing structures (RASs), magnetic and dielectric materials are blended in different proportions because the impedance mismatch of dielectric materials, resulting from poor permeability, can be eliminated by a combination with magnetic loss fillers. Herein, E-glass/epoxy composites were prepared by blending multi-walled carbon nanotubes (MWCNTs) with Ni0.5Zn0.5Fe2O4 (NZF) nanopowder to enhance the composites’ microwave absorption. Nanocomposite laminates with different filler contents were fabricated by a simple and low-cost process of in situ polymerisation. The dielectric characteristics were estimated in the X-band, and possible loss mechanisms were studied. A two-layered RAS exhibited a reflection loss of −16 dB for a bandwidth of 2.2 GHz with a matching thickness of 3 mm. The resulting mechanical and thermal properties suggest that the proposed MWCNTs/NZF composite exhibiting good microwave absorption properties can be used in high-performance RASs.

Ni0.4Zn0.6Fe2O4 Nanopowders by Solution-Combustion Synthesis: Influence of Red/Ox Ratio on their Morphology, Structure, and Magnetic Properties

Nickel-zinc ferrite nanopowders Ni0.4Zn0.6Fe2O4 were prepared by glycine (G)–nitrate (N) solution-combustion synthesis and the influence of G/N ratio on their chemical composition, morphology, structure, crystallite size, and magnetic behavior was characterized by XRD, EDX, SEM, FTIR spectroscopy, and vibration magnetometry. According to XRD data, the formation of Ni–Zn ferrite gets started at G/N = 0.4. The observed influence of G/N ratio on the structural and magnetic parameters of Ni–Zn ferrites opens up a route to producing powders with crystallite size D in the range 24.6–47.1 nm, extent of conversion α up to 94%, coercive force Hc from 7.88 to71.78 Oe, remanence magnetization Mr from 2.42 to 31.81 emu/g, and saturation magnetization Ms from 51.06 to 90.66 emu/g. The maximum values of magnetic characteristics were reached at a stoichiometric ratio of glycine to nitrogen in nitrates (G/N = 0.6).

Magnetic Ni-Zn spinel ferrite nanopowder from toxic Zn-bearing electric arc furnace dust: A promising treatment process

Zn-bearing electric arc furnace dust (ZEAFD) generated as a by-product of steel manufacture is classified as a toxic solid waste. To date, there has been little research concerning facile and efficient utilization of the valuable metallic elements (such as Zn, Fe, Mn and Cr) in this material. In this study, a metal co-doped (Ni,Zn)Fe2O4 nanopowder having excellent magnetic properties was successfully synthesized by a solid state calcination method based on adding Ni(OH)2 to the ZEAFD to compensate for a lack of divalent ions. The effects of the ZEAFD to Ni(OH)2 mass ratio and of the calcination temperature on the phase transformations, microstructures and magnetic characteristics of the resulting ferrites were investigated using various analytic techniques. A pure phase metal co-doped (Ni,Zn)Fe2O4 nanopowder having a higher saturation magnetization (57.3 emu·g−1) and lower coercivity (58.8 Oe) was obtained when the mixture was calcined at 1000 °C for 2 h with a mass ratio of 2:0.9, followed by washing with dilute acetic acid (pH = 2.88). This synthesized metal co-doped ferrite was also assessed using the United States Environmental Protection Agency toxicity characteristic leaching procedure and found to be non-toxic. This process provided overall dust utilization percentages as high as 76.0%.

Evaluation of mechanical, optical and thermal properties of PVA nanocomposites embedded with Fe2O3 nanofillers and the investigation of their thermal decomposition characteristics under non-isothermal heating condition

Magnetic Fe2O3 nanopowder was synthesized and characterized by various analytical techniques. The PVA/Fe2O3 nanocomposites were prepared by solution casting method to investigate the effect of nanofillers on their physicochemical properties. The analytical tools such as FTIR, UV–visible spectra and XRD were used to analyze the structure of Fe2O3 nanopowder and PVA/Fe2O3 nanocomposites. The uniform distribution of the Fe2O3 nanofillers on the PVA matrix was inspected using SEM. The particle size of the crystalline Fe2O3 nanofillers was observed to be less than 30 nm from the TEM micrographs. The optical characteristics of the prepared samples were investigated by analyzing their UV–visible spectra. The bandgap of PVA nanocomposites was lower than for pure PVA due to the dispersed Fe2O3 nanofillers in the PVA matrix. The thermal properties of pristine PVA and PVA/Fe2O3 nanocomposites were investigated by TGA. The PVA/Fe2O3 nanocomposite systems exhibited the improved thermal stability. The thermal degradation mechanism of PVA/Fe2O3 nanocomposite system was inspected in depth at five different heating rates under non-isothermal conditions. The electrical and mechanical properties of PVA were enhanced remarkably while increasing the % weight loading of nanopowder.

Optical and electrical characteristics of thin PMMA sheets doped with Cu–Zn ferrite nanoparticles

In this work, polymeric sheets doped with different percentages of Cu0.5Zn0.5Fe2O4 nanopowders were synthesized. The ferrite powder was prepared by coprecipitation technique and mixed with polymethylmethacrylate (PMMA) in chloroform solvent solution at room temperature. The formed ferrites/PMMA composite sheets were of gradual transparency from clear to dark brown appearance according to the doped ferrite concentration. The microscopic images showed homogenous distribution of ferrite powder over the whole area of the formed sheets with good stability and smooth surface. The UV–visible absorption spectra of the samples were measured, and optical energy gaps were determined for all the samples. The photoluminescence emission spectra of the polymeric composite were measured. Dielectric properties were investigated in AC field. The frequency dependence of dielectric constant and conductivity showed semiconducting behavior which was explained in view of the electrical conduction mechanisms of ferrites and polymers.

The structural study, Hirshfeld surface analysis, and DFT calculations of ferrocenyl-hydrazine Schiff base: A novel precursor for the selective preparation of Fe2O3 nanoparticles

Ferrocenyl-Hydrazine Schiff base (FHS) was synthesized via a reaction between acetylferrocene and 2, 4-dinitrophenylhydrazine at stoichiometric 1:1 M ratio at 70 °C for 4 h. The crystal structure of the Schiff base was determined by single crystal X-ray diffraction (XRD) technique. The compound was crystallized in a tetragonal crystal system with a space group I41/a. Also, the physical properties of the product were studied by FT-IR, UV-Vis spectroscopies, and density functional theory (DFT) calculation. In this study, inter-molecular interactions were investigated using Hirshfeld surface analysis. Fe2O3 nanopowders (S1) were synthesized by thermal decomposition synthesis by ferrocenyl 2, 4-dinitrophenylhydrazine (FHS) at 800 °C for 8 h. According to TG data, 800 °C was chosen as the reaction temperature. Crystallite nature and phase purity of the prepared compounds were investigated via PXRD and FT-IR techniques. Structural analyses were performed by the FullProf program employing profile matching with constant scale factors. The results showed that the patterns had a main hexagonal structure with a space groupR3−C. The morphological and structural properties of the obtained materials were examined by FESEM images. The photocatalytic performance of the synthesized nanomaterial was studied under the following photocatalytic conditions: 0.1 mL H2O2 and 30 mg catalyst for the removal of methyl orange, rodamin B, alizarin, malachite green (MG), xylenol orange in aqueous solutions under direct visible and UV-Vis light irradiations.

Mg0.5Ni0.5Fe2O4 nanoparticles as heating agents for hyperthermia treatment

AbstractIn the present work, Mg0.5Ni0.5Fe2O4 nanopowders were prepared by a sol‐gel combustion method. The magnetic properties, heat generation ability in an AC magnetic field and cytotoxicity of the mixed ferrite nanopowders were investigated. The results showed that the powders have crystalline spinel structure with a particle size in the range of 20‐90 nm. Maximum saturation magnetization (Ms) of 51 emu/g was obtained for the Mg0.5Ni0.5Fe2O4 nanoparticles calcined at 900°C. The results showed that, the coercivity (Hc) of the Mg0.5Ni0.5Fe2O4 initially increases up to 700°C and then decreases with increasing temperature, whereas the Ms of the samples continuously increases. The Mg0.5Ni0.5Fe2O4 sample exhibited a temperature increase up to 45°C during 10 minutes in the exposure of magnetic field of 200 Oe. By increasing the viscosity of ferrofluid, the heat generation ability of nanoparticles reduced up to 9% at magnetic field of 200 Oe. Cell compatibility of the ferrite powders was studied by MTT assay using MG63 cell line proliferation. MTT results showed that calcination temperature of the Mg0.5Ni0.5Fe2O4 nanoparticles significantly affects the cell compatibility.

La-doped Ni0.5Co0.5Fe2O4 nanoparticles: effect of cobalt precursors on structure and morphology

The effect of cobalt precursors (cobalt acetate and cobalt nitrate) on the phase stability and evolution of morphology of La-doped Ni0.5Co0.5Fe2O4 nanopowders prepared via sol-gel auto-combustion method has been investigated. XRD analysis indicates the formation of single cubic spinel phases, while the crystallite size is found smaller when using cobalt acetate precursor. The Williamson-Hall plot has been used for estimating the crystallite size and lattice strain. SEM observations reveal homogenous and slightly agglomerated particles. EDS analysis confirms that the chemical composition was close to the nominal stoichiometry. The interionic distances cation-cation, cation-anion and bond angles have been calculated. FTIR spectra contain two absorption bands in the range from 400 to 600 cm−1 which confirm the formation of the spinel structure.

Neutron Diffraction Analysis and Electromagnetic Properties of Ultrasonic Wet-Magnetic Separated NixZn1−xFe2O4 Nano-powders

Nano-sized ferrite powders less than 50 nm were prepared through combustion reaction followed by pulverizing and separating through ultrasonic-wet magnetic classification processes to study the electromagnetic properties of the nano-sized ferrites for developing an high performance electromagnetic interference filter. Neutron diffraction analysis of the ferrites prepared at 10 MPa of oxygen pressure shows that the final phase is Ni0.33Zn0.67Fe2O4 (χ2 = 1.48), which lattice parameter is 0.8412(2) nm. The residual magnetization, maximum magnetization, coercive force, susceptibility and Curie temperature of Ni0.33Zn0.67Fe2O4 particles are 0.88 Wb/m2 kg, 7.749 Wb/m2 kg, 1292 A/m, 0.068 m3/kg, and 413.93 K, respectively. Finally, the nano-sized ferrite particle less than 50 nm with more than 99% purity were obtained. The increasing frequency reduced complex permeability which real value (μr0) shows the maximum value at the less than 0.5 GHz. The dielectric constants of the powders are er′ = 5.7 and er″ = 2.5. The nano-sized Ni0.33Zn0.67Fe2O4 ferrite absorber works effectively in the range of 3–5 GHz. Typical FESEM image of Ni0.33Zn0.67Fe2O4 nano-powders.