NiFe2O4 Phase Research Articles

Optimizing the resistance of Cr-advanced steel to CO2 corrosion with the addition of Ni

The findings of this study indicate that Cr-advanced steels exhibit increased corrosion resistance when Ni is incorporated into the alloy. To investigate this phenomenon, the corrosion products and corrosion behavior of Cr-advanced steels with varying Ni contents were evaluated in CO2-saturated NaCl solutions at 90 and 180 °C. The underlying corrosion resistance mechanism can be elucidated from two distinct perspectives. At 90 °C, the addition of Ni into Cr-advanced steels causes the transformation of Fe oxides to NiFe2O4, and it offers superior protection for steel. In addition, the NiFe2O4 phase generated with electronegative properties can enhance the adsorption of Fe2+, thereby promoting the precipitation of FeCO3 crystals. Furthermore, the residual Ni in the inner film continues to serve a pivotal role in the filling of a considerable number of pores and cracks. Upon comprehensive evaluation of the associated costs, the Cr-advanced steel with enhanced corrosion resistance through the incorporation of 1.0 wt% Ni content provides a potential alternative to a conventional 3Cr steel in a CO2 environment. On the other hand, at 180 °C, the concentrations of Fe2+ and CO32− are significantly higher than the solubility of FeCO3 in initial corrosion, which is conducive to generate a denser nanometer-size FeCO3 layer with a better protectiveness, and thus, the effect of Ni is significantly weakened.

Dissolution‑recrystallization growth and structural characteristics of facile decomposition-processed NiFe2O4 octahedrons

In this paper, NiFe2O4 powders were prepared by a thermal decomposition process with various temperatures. The structural characteristic and intrinsic defect were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, ultraviolet–visible (UV–vis) spectroscopy, and photoluminescence (PL). The morphology was investigated by scanning electron microscope (SEM) and transmission electron microscope (TEM). XRD pattern reveals the pure NiFe2O4 phase as the calcination temperature of 900 and 1,000 °C. The calcination of 900 °C depicted the micro-octahedral structures with a smooth surface. The calculated hopping length and the FT-IR spectra reveal the cation shifting from octahedral to tetrahedral structure. The decreasing energy bandgap of NiFe2O4 was investigated as the calcination temperature increased. The PL transition of 3A2g(3F) → 3T1g(3F) refers to the band-to-band emission. The structural characteristics, morphology, and defects were investigated and discussed in terms of phase, bonding vibration, crystal growth mechanism, emerging energy level and electron transition.

Large-scale NiFe2O4-based cermets prepared by composite extrusion modelling: From high-qualified composite feedstock to dense sintered microstructure

Combining with the advantages from mature technologies of fused deposition modelling and powder injection molding, 3D NiFe2O4-based cermet with weight over 1.3 kg and relative density of 95.8 % were fabricated by composite extrusion modelling using polyoxymethylene-based feedstock. Microstructure and rheological properties of the feedstock, roles of printing parameters on the morphology green samples and related catalytic debinding, sintering properties of cermets were investigated in detail. Uniformly dispersed cermet powders in feedstock were confirmed, due to the good wettability between the powders and binders. The feedstock with high solid loading of 58 vol% exhibited shear-thinning behavior and contained high storage modulus for reliable shape retention. With optimized printing parameters, a high compression ratio (layer height/nozzle diameter) over 2.5 tended to shrink the size of stacking pores, resulting in dense green samples. Catalytic debinding was proved to be defect-free and efficient debinding route, which was successfully used to deal with dense cubic samples with thickness of 30 mm. Sintered samples showed uniform microstructure with interconnected FeCuNi and Ni(Fe)Fe2O4 phases. Except for partial stacking pores in the fracture section, polished cermets exhibited mirror-like surfaces, indicating the good controlling of the final microstructure and performance of 3D cermets.

Improvement of the magnetoelectric response in NiFe2O4−Sr0.5Ba0.5Nb2O6 composites using LiNbO3 as sintering additive

Magnetoelectric (NiFe2O4)0.3−(Sr0.5Ba0.5Nb2O6)0.7 composites with addition of LiNbO3 as sintering additive were prepared by a classical mixed-oxide method. XRD patterns of ceramics sintered between 1000 and 1200 °C show the desired Sr0.5Ba0.5Nb2O6 and NiFe2O4 phases. SEM investigations confirm the 0–3 connectivity of the composite ceramics. The addition of 10 and 20 mol% LiNbO3 improves the densification of the composite ceramics and leads to an increase of the size of the Sr0.5Ba0.5Nb2O6 grains. Magnetic measurements show hystereses with low coercivities. Dielectric measurements were carried out depending on temperature and frequency. The samples with the LiNbO3 addition show significantly higher resistivity values (σDC). Magnetoelectric measurements were carried out in dependence of the magnetic DC-field, temperature, and frequency. The maximum magnetoelectric coefficient (αME) rises with the addition of LiNbO3 from 180 to 803 µV Oe−1 cm−1 (@900 Hz). Temperature dependent measurements show a continuously decreasing of αME with lower temperature.

Effect of calcination temperature on the attrition and activity of CuO/NiO/olivine for producing syngas in biomass chemical looping gasification

An oxygen carrier (OC), with a long lifetime and better reactivity, has become the key to the biomass chemical looping gasification (BCLG) process. In this study, CuO and NiO supported on olivine (Cu/Ni/O) was prepared at different temperatures (900–1300 °C). Various characterizations including XRD, SEM, BET, H2-TPR, TG and TG-FTIR were used to investigate the effect of calcination temperature on the composition, morphology, multiple redox, oxygen carrying capacity and activity of the resultant OCs. And the BCLG experiments were conducted in a micro fluidized bed reactor (MFBR) to examine the performance of OCs. The results showed that CuFe2O4 and NiFe2O4 phases were observed after CuO and NiO were loaded onto peridot. The increase of calcination temperature results in the decrease of surface area and oxygen-carrying capacity of the OC to 1.305 m2/g and 1.93 wt% at 1300 °C from 4.760 m2/g and 3.60 wt% at 900 °C. The final weight loss of OCs with cotton stalk (CS) showed the same variation trend as that of redox process of OCs. However, the anti-resistance of the OC was greatly improved, especially the 1100-Cu/Ni/O calcinated at 1100 °C showed better anti-resistance with the attrition rate of 0.09 wt% and pulverization rate of 0.41 wt%. Under the optimal operating conditions (mass ratio of OC to biomass = 30:1, steam injection rate = 0.05 g/min and temperature = 800 °C), the highest gasification efficiency of 59.2 % and syngas yield of 0.71 Nm3/kg were obtained over 1100-Cu/Ni/O. The cyclic experiments demonstrated better anti-sintering and cyclic performances of 1100-Cu/Ni/O, which made it very attractive for the BCLG.

Structural and magnetic characteristics of NiO/NiFe2O4/α-Fe2O3 nanocomposite

Effect of Fe concentration in forming NiO/NiFe2O4/α-Fe2O3 nanocomposite (NC) was probed through structural and magnetic characterizations. Presence of two-magnon mode in Raman spectra confirms the existence of NiFe2O4 and α-Fe2O3 phases in the background of antiferromagnetic (AFM) NiO matrix. Magnetic study further confirms the occurrence of weak ferromagnetism in the AFM background. The behaviour of temperature dependence of saturation magnetization revealed that the samples exhibit some type of inhomogeneity. The NC samples show robust exchange bias characteristics at room temperature. The occurrence of ferromagnetic like feature in the NC samples could be due to the combine effect of the formation of BMP along with the magnetic inhomogeneity. The samples show the persistence of robust exchange bias field at 300K. The amplification of anisotropic constant with higher Fe concentration in the NC sample could be ideal for device applications like magnetic recording media.

Design, fabrication, and magnetic properties of novel (Ni,Cr,Zr)-co-doped M-type barium ferrite ceramics

Multicomponent co-doping is an effective method to balance the counteracting magnetic properties of ferrite ceramics. In this work, novel (Ni,Cr,Zr)-co-doped M-type barium hexaferrites (BaFe12-3xNixCrxZrxO19, x = 0–0.8) were designed and synthesized by traditional solid-state reaction. Thermogravimetric analysis indicated that NiO would participate in the formation of secondary phase NiFe2O4 in the as-synthesized powder. Through traditional solid-state sintering, by using the synthesized pure-phase magnetic powders, almost full-dense ceramics were fabricated. Visual high-temperature deformation analysis revealed that there was no obvious difference in the sintering behavior and densification temperature of the ceramics with different compositional x, due to the low sintering activity of the as-synthesized magnetic powders. And X-ray diffraction analysis indicated that all the fabricated ceramics are of pure-phase M-type barium ferrite, and the lattice parameter c/a firstly increased as x raised up to 0.4 and then remained almost unchanged with further increased x, even if the lattice distortion became heavier. Microstructure examination revealed that the grain size monotonously decreased as the quantity of the substituent ions increased. The remnant magnetization and coercivity of the fabricated ceramics decreased monotonously as x increased, while the saturated magnetization could be maintained till the samples with x ≤ 0.4. Taking all the parameters into consideration, the samples with x = 0.4 might be a good candidate for transformer cores.

Development of Lead Free Magnetoelectric Materials for Magnetic Field Sensor applications

(100-x) Na0.5Bi0.5TiO3 (NBT)-(x) NiFe2O4 (NFO)(x = 0, 20, 40, 60, 80 and 100) composites are synthesized using conventional solid state reaction method. Crystal structure studies are performed by using X-ray Diffraction technique (XRD) and the Rietveld analysis of XRD patterns confirms the co-existence of cubic (NFO) and rhombohedral (NBT) symmetry with Fd- 3m and R3c space groups, respectively. Micro-structural study reveals the formation of combination of composite phases and its inter-coupling grains. The average grain sizes and area percentage of each phase for the composites are calculated using Image J software. The Magnetisation versus Magnetic field (M-H) hysteresis loops show soft magnetic behavior of composites with variation in Saturation magnetization (MS) and Coercivity (HC). A maximum MS (34 emu/g) and low HC (15 Oe) is obtained for (80) NFO - (20) NBT composite.The Polarization – Electric field (P-E) analysis shows that the maximum saturation polarization (PS) is obtained for (60)NBT-(40)NFO sample and is attributed to the leakage current generated by conductive NFO phase. The coupling between the ferrite and ferroelectric phase is studied based on the magnetoelectric voltage coefficient(αME). The maximum (αME) of 1.82 mV/cm-Oe is obtained for (80)NBT -(20)NFO sample and this is almost 80% higher than the previously published literature on NBT-NFO composites. This can be attributed to the uniform distribution of grains with each ferroelectric phase surrounded by ferrite phase as shown in the morphological study.

Foamed Carbon-Supported Nickel-Iron Oxides Interspersed with Bamboo-Like Carbon Nanotubes for High-Performance Rechargeable Zinc-Air Batteries.

The development of multi-component bi-functional electrocatalysts is necessary for commercialization of high-performance zinc-air batteries. Herein, foamed carbon-supported nickel-iron oxides interspersed with bamboo-like carbon nanotubes are prepared as bi-functional electrocatalysts for this battery type. During high temperature synthesis, edges of carbon sheets comprising the foamed carbon structure become involuted to form short carbon nanotubes. The composite of carbon nanotubes and network carbon confer high specific surface area and high electrical conductivity on the newly prepared materials. The supported NiFe2 O4 phase improves the oxygen reduction reaction (ORR) activity by fixing more N atoms, and high-valent Ni oxide (Ni2 O3 ) promotes the formation of OO bonds, which is conducive to the oxygen evolution reaction (OER). The optimized material exhibits excellent bi-functional electrocatalytic activity toward both ORR and OER, and its use in the assembled zinc-air battery cell results in a high power density of 150mWcm-2 with long discharge stability.

Electrolytic Corrosion Behavior of 20 Cu-20 Ni-54 NiFe2O4-6 NiO Cermet with Interpenetrating Structure at 880 °C and 960 °C.

Here, 20 Cu-20 Ni-54 NiFe2O4-6 NiO (wt%) cermets were prepared via the powder metallurgy process, and the electrolytic corrosion behavior of the cermets at 880 °C and 960 °C was studied through the microstructure analysis by SEM and EDS. Results show that the ceramic phase is seriously affected by chemical corrosion at 880 °C electrolysis, and it is difficult to form a dense ceramic surface layer. A dense ceramic surface layer is formed on the bottom of the anode electrolyzed at 960 °C, and the dense layer thickens with the extension of the electrolysis time. The formation of the dense surface layer is mainly caused by the oxidation of Ni. The oxidation rate of the metallic phase and the corrosion rate of the ceramic phase have an important effect on the formation of the dense layer. In the corrosion process of NiFe2O4 phase, preferential corrosion of Fe element occurs first, and then NiO phase is precipitated from NiFe2O4 phase. After the NiO is dissolved and corroded, the NiFe2O4 grains collapse and the ceramic phase peels off from the anode.

Electrical, magnetic and microwave absorption properties of multiferroic NiFe2O4-BaTiO3 nanocomposites

Multiferroic nanocomposites of xNiFe2O4/(1-x)BaTiO3 (x = 0, 0.1, 0.2, 0.3, and 0.4) (denoted as NFO-BTO) with the particle size about of 70 nm were prepared by the high energy mechanical milling combined with the thermal annealing methods. The x-ray diffraction patterns show a presence of NiFe2O4 (NFO) and BaTiO3 (BTO) phases. The values of the characteristic parameters of nanocomposites such as the coercive field (E c), the residual polarization (P r), the remanent magnetization (M r), the saturation magnetization (M s), and the coercive force (H c) increase gradually with an increase in NFO concentration. For an applied electric field below 10 kV cm−1, the values P r and E c are found to be 0.004–0.038 μC cm−2 and 0.7–2.0 kV cm−1, corresponding x = 0.1–0.4, respectively. Changes in electrical and magnetic properties of composites depend heavily on the NFO content, which will be studied specifically. Additionally, the ability to absorb microwave at room temperature of a representative sample with x = 0.3 mixed in acrylic paint (denoted as NFO-BTO-AP) in a frequency range of f = 12–18 GHz has also been investigated. It shows a large negative reflection loss (RL) with RL = −39.8 dB occurring at around 16.8 GHz corresponding to the absorptivity of over 99.9% for an absorbing layer with thickness of 5.5 mm. This suggests that NFO-BTO nanocomposites could be considered as a potential material in the field of absorbing and shielding electromagnetic waves.

Dielectric and ferroelectric properties of multilayer BaTiO3/NiFe2O4 thin films prepared by solution deposition technique

In this work different lead-free multilayered structures, composed of perovskite BaTiO3 and spinel NiFe2O4 thin layers, were obtained by solution deposition method. Structural characterization of the sintered thin films confirmed the well-defined layered structure with overall thickness from 160 to 600 nm, crystalline nature of perovskite BaTiO3 and spinel NiFe2O4 phases without secondary phases (after sintering below 900 °C) and grains on nanometer scale. Dielectric properties of the multiferroic multilayer BaTiO3/NiFe2O4 thin films were analyzed in temperature and frequency range from 30 °C to 200 °C and 100 Hz to 1 MHz, respectively. In comparison to the pure BaTiO3 films, the introduction of ferrite layer reduces dielectric response and increases low frequency permittivity dispersion of the multilayer thin films. The multilayer samples have shown relatively low dielectric loss with stronger contribution of conductivity at higher temperatures, and characteristic broad peak representing “relaxation” of the interface charge accumulation.

Phase structure refinement, electric modulus spectroscopy, Urbach energy analysis, and magnetic properties of Ce3+–Ni2+-substituted Y-type barium hexaferrites

In this work, the influence of Ce3+–Ni2+ substitution on the properties of sol-gel–synthesized Y-type hexaferrites with the following chemical composition is investigated: Ba2-xCexZn0.7Co0.7Cu0.6Fe12-yNiyO22 (x = 0.0, 0.4, and 0.6; y = 0.0, 0.5, and 0.7). X-ray diffraction analysis reveals the presence of a few NiFe2O4 and Fe3O4 secondary phases in the substituted samples (M2 and M3). The Fourier-transform infrared bands at 430, 543, and 582 cm−1 are characteristic bands of iron-oxides, which indicate the vibrations of the octahedral and tetrahedral sites in the S-block of the Y-type hexaferrite. The morphology analysis reveals agglomerated grains, which were generated by weak Van der Waals force and magnetic interaction. The optical analysis reveals the presence of an Urbach energy tail. The electrical properties were investigated based on the Maxwell–Wagner two-layer model and Koop’s phenomenological theory. Increase in the magnetization is observed by substituting Fe3+ with Ni2+ and was studied according to the ligand-field theory.

Effects of morphology on the electrochemical performance of NiFe2O4nanoparticles with battery‐type behavior

AbstractWe report the synthesis of NiFe2O4nanoparticles by the complexation EDTA‐citrate method under acidic (pH = 3) and basic (pH = 9) conditions. The structural, optical, vibrational, magnetic, and electrochemical properties were studied. The samples have crystallite sizes of 21 nm (pH 3) and 73 nm (pH 9), with rounded particles and layered structures. The57Fe Mössbauer spectra at 12 K showed that both samples had an inverse spinel cation distribution. At 5 K, the sample prepared at pH 9 showed saturation magnetizations of about 50 emu/g. Raman spectra showed typical bands of NiFe2O4phase. The materials were tested as electrodes under alkaline condition. The cyclic voltammetry and charge‐discharge experiments indicated a battery‐type behavior, with maximun capacities of 65 and 5 C/g (at specific currents of 3 and 10 A/g) for samples prepared at pH 9 and 3, respectively. This work offers a route for obtaining NiFe2O4nanoparticles with different morphologies and sizes tuned by the synthesis conditions.

Structural and magnetic properties of a BaFe12O19/NiFe2O4 nanostructured composite depending on different particle size ratios

A nanostructured magnetic composite based on hexagonal ferrite BaFe12O19 (magnetically hard) and cubic ferrite NiFe2O4 (magnetically soft) is synthesized. The hexagonal ferrite precursor is obtained by the Sol-Gel method using citric acid as a coordinating agent. The precursor obtained is heated at different temperatures to get nanoparticles with different sizes. Cubic ferrite is obtained by chemical co-precipitation, method and the nanoparticle growth process is controlled with different heat treatments. The hexagonal and cubic ferrite nanoparticles are mixed providing low energy. Three samples of this kind of composite are obtained with a different ratio of particle size. The composites are a mixture where there are clusters of the minority phase NiFe2O4 distributed in a matrix of the main phase BaFe12O19. Both ferrite phases are composed of nanoparticles with an average size less than 50 nm without tensions in the crystal lattice. These structural parameters were compared between the composites and their precursor ferrites. The relationship between the composite microstructures and their magnetic properties is analyzed. A weak exchange coupling was detected between the component magnetic phases of the composites. Depending on the synthesis conditions, some samples exhibit monodomain or a multidomain regime. The higher BH product appears for composites from ferrites with a nanoparticle size ratio approximately equal to one. The structural characterization is carried out by X-ray diffraction. The homogeneity of the composition in the volume of the nanostructured composites is analyzed with a field emission scanning electron microscope equipped with energy dispersive spectroscopy for the analysis of the element mapping. The magnetic study is carried out through measurements of magnetization as a function of the applied field (M vs. H) at 300 K.

Three-phase composites of NiFe2O4/Ni@C nanoparticles derived from metal-organic frameworks as electrocatalysts for the oxygen evolution reaction

Composite electrocatalysts of carbon and metals or metal compounds with homogeneous active sites can be obtained through the carbonization of metal organic framework (MOF) materials under inert atmosphere. In this work, a three-phase composite electrocatalysts NiFe2O4/Ni@C were prepared via pyrolysis from self-assembled MOF nanosheets aggregates. The excellent electrocatalytic activity of the obtained electrocatalysts with various Ni:Fe ratios is demonstrated. Especially, the NiFe2O4/Ni@C sample with the mole ratio of Ni:Fe = 1:1 can use the overpotential (η) of 330 and 423 mV to drive 10 and 50 mA cm−2 respectively. After 80 000 s/22 h, the current density could retained 90% of the initial current density. The excellent activity and stability of the electrocatalysts are attributed to nickel and iron ions with uniform dispersion at atomic level in the NiFe2O4 phase and the synergistic effect of nickel and NiFe2O4 nanoparticles with amorphous carbon atoms or nanoparticles around.

Fabrication of magnetically recoverable BiVO4/NiFe2O4 composites for the photocatalytic degradation of methylene blue

Bismuth vanadate (BiVO4) and nickel ferrite (NiFe2O4) nanoceramics were successfully synthesized using hydrothermal and sol-gel methods, respectively. Three different composites between magnetic NiFe2O4 and non-magnetic BiVO4 phases (25 wt% BiVO4 + 75 wt% NiFe2O4, 50 wt% BiVO4 + 50 wt% NiFe2O4 and 75 wt% BiVO4 + 25 wt% NiFe2O4) were prepared and characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and UV–Visible spectroscopy. The PXRD analysis indicated the formation of well-defined composites between the two phases. All three composites were found to be magnetic in nature as confirmed from magnetic measurements carried out using vibrating sample magnetometer (VSM). The saturation magnetization (Ms) values found to be decreased almost linearly with increasing BiVO4 content in the composite, due to magnetic dilution induced in the composites by the non-magnetic BiVO4 phase. Band gaps of all the as-synthesized compounds were determined using diffuse reflectance spectroscopy (DRS) and are found to be in the visible region which makes them suitable for the photocatalytic dye degradation application. Among all the prepared magnetic composites, the composite with 50 wt% BiVO4 + 50 wt% NiFe2O4 exhibited the highest photocatalytic activity towards the degradation of 10 ppm methylene blue solution. Further enhancement of photocatalytic efficiency was achieved by the addition of a known volume of H2O2. Overall, 80% dye degradation efficiency was achieved using the composite of 50 wt% BiVO4 + 50 wt% NiFe2O4 under sunlight. Since the composites are magnetic in nature they can be easily separated from the heterogeneous reaction mixture using a laboratory magnet, after the photocatalytic treatment.

Effect of doping Al on the microstructure of Cu-Ni-NiFe2O4-NiO cermets

Cu-Ni-NiFe2O4-NiO cermets doped with Al (0, 0.8, 2, 3.2 wt% ) were prepared by a powder metallurgy process. The effect of Al content, Al adding method and sintering temperature on the microstructure of the cermets were studied using XRD, SEM/EDS, and DSC. The results show that NiO and NiFe2O4 phase are partly reduced to Ni by adding Al at the sintering temperature. The Al element is mainly distributed in the NiFe2O4 phase, and the doping of Al is not conducive to the densification of cermet. The density of the cermet decreases with increasing Al content. The morphology of the metallic phase is related to the Al adding method. Specimens prepared by pre-alloying of Al show smaller metallic particle size than that by mixing of Al. However, the Al adding methods have little effect on the densification and the phase composition. The sintering temperature around the solid phase line of the metallic phase is beneficial to the densification.

Structural, Magnetic, and Electrical Properties of (1-x) Na0.5Bi0.5TiO3 –(x) NiFe2O4(x = 0.1, 0.3, 0.5, 0.7, and 0.9) Multiferroic Particulate Composite

Multiferroic composites consisting of Na0.5Bi0.5TiO3(NBT) and NiFe2O4(NFO) phases have been synthesized by using sol-gel and metal-organic decomposition (MOD) methods. The X-ray diffraction (XRD) and scanning electron microscopy (SEM) results confirm NBT and NFO phase formation in all composite samples without the presence of any intermediate phases. The phonon vibrational modes of the composite samples are detected by Raman spectroscopy over wavenumber regions from 100 to 1000 cm−1 at room temperature. The dielectric constant and dielectric losses are measured over a wide range of frequencies from 1 kHz to 1 MHz at room temperature. Room temperature magnetization measurements confirm the ferromagnetic behavior of all the composite samples. The observed values of coercivity are significantly lower and lie between 9.5 and 49 Oe only, which signifies the soft magnetic behavior of samples. The highest leakage current density value (3.39 × 10−6) has been observed for 50NBT-50NFO composite in I–V measurements. The present study reveals that NBT-NFO composites could be potential lead-free multiferroic composites and provide an alternative for designing environment-friendly devices.

Synthesis and Characterization of Nanocrystalline Fe(100−x)Ni(x) Alloy Powders by Auto-combustion and Hydrogen Reduction

Nanocrystalline Fe90Ni10, Fe70Ni30 andFe50Ni50 alloy powders were successfully synthesized using a simple auto-combustion route followed by hydrogen reduction. The experimental work consisted of two steps, where the first step was auto-combustion and, the second step was reduction of the combusted powders. Citric acid was used as fuel during combustion, and citrate to nitrate ratio (C/N) was maintained at 0.3. NiFe2O4 and Fe2O3 phase formation occurred in obtained powders. Obtained powders were reduced in a hydrogen atmosphere at 700 °C/1 h for alloy formation. X-ray diffraction results revealed the presence of BCC α-(Fe,Ni) and FCC γ-(Fe,Ni) phases in reduced powders. Rietveld refinement technique was used to confirm α-(Fe,Ni) and γ-(Fe,Ni) phases with Im-3 m and Fm-3 m space groups, respectively. The Fe50Ni50 powder has been found to have a single γ-(Fe,Ni) phase. Crystallite size of synthesized powders was calculated using the Scherrer equation and transmission electron microscopic analysis, which has been found < 50 nm. The nanocrystalline powders of all three compositions have shown soft magnetic nature with high saturation magnetization (Ms) and low coercivity (Hc). Effect of composition on the phase formation, microstructure and magnetic behavior was investigated. This rapid and simple process for attaining nanoparticles of Fe-Ni alloys with high Ms is expected to be useful in potent applications such as sensors, biomedical applications and electromagnetic wave absorbers.