Lithium ferrite (Li0.5Fe2.5O4) nanoparticles as anodes for lithium ion batteries

Li0.5Fe2.5O4 nanoparticles of about 80 nm were synthesized through a hydrothermal method, followed by a solid state reaction between LiOH·H2O and Fe2O3. The Li0.5Fe2.5O4 nanoparticles exhibit a remarkable high capacity (up to 1124 mA h g-1), a good cycle stability (650 mA h g-1 after 50 cycles) and excellent coulombic efficiency. © 2014 the Partner Organisations.

Fabrication and visible-light photocatalytic behavior of perovskite praseodymium ferrite porous nanotubes

Perovskite praseodymium ferrite (PrFeO3) porous nanotubes are prepared by electrospinning of the precursor solution into nanofibers, subsequently by annealing the precursor fibers at a low temperature (e.g. 40 °C) and finally by calcination at a high temperature. The low temperature annealing treatment is found to play a key role in the formation of porous nanotube. The porous tubes show a perovskite-type PrFeO3 crystal characteristic with high optical absorption in the UV-visible region and an energy band gap of 1.97 eV. When compared with PrFeO3 porous nanofibers and PrFeO3 particles, the PrFeO3 porous nanotubes show better visible-light photo-catalytic ability to degrade Rhodamine B in aqueous phase because of the increased surface area and more active catalytic sites on the inner walls and outer surfaces.

Study of growth mechanism of TiC cluster in ferrite via molecular dynamics simulation

Abstract Atomistic simulations were used to investigate the evolution process of titanium carbide clusters to mature precipitates in ferrite. The typical kinetic of carbide cluster growth was studied in detail through analyzing the atomic interactions of a carbide cluster with scattered carbon atoms. The driving force required for cluster growth was calculated along with the atomic diffusivity in the iron matrix, exploring the change in response as two main growth steps. The growth kinetic improved the understanding of precipitate evolution at the atomic level.

Zinc doped ferrite magnetic resonance imaging contrast agent for atherosclerosis

 This project focuses on the development of zinc doped ferrite nanoparticle based MRI contrast agents with enhanced contrast and site-specific targeting for atherosclerosis diagnosis. The engineered nanocomplexes developed were validated through MRI scans using rat models with potential for multimodal imaging and effective therapy.

Effect of δ-ferrite co-existence on hot deformation and recrystallization of austenite

This work evaluates the effect of co-existence of a large volume fraction of δ-ferrite on the hot deformation and dynamic recrystallization (DRX) of austenite using comparative hot torsion tests on AISI 304 austenitic and 2205 duplex stainless steels. The comparison was performed under similar deformation conditions (i.e. temperature and strain rate) and also under similar Zener-Hollomon, Z, values. The torsion data were combined with electron backscatter diffraction (EBSD) analysis to study the microstructure development. The results imply a considerable difference between DRX mechanisms, austenite grain sizes and also DRX kinetics of two steels. Whereas austenitic stainless steel shows the start of DRX at very low strains and then development of that microstructure based on the necklace structure, the DRX phenomena in the austenite phase of duplex structure does not proceed to a very high fraction. Also, the DRX kinetics in the austenitic steel are much higher than the austenite phase of the duplex steel. The results suggest that at a similar deformation condition the DRX grain size of austenitic steel is almost three times larger than the DRX grains of austenite phase in duplex steel. Similarly, the ratio of DRX grain size in the austenitic to the duplex structure at the same Z values is about 1.5.

The formation of ultrafine ferrite through static transformation in low carbon steels

A novel approach was used to produce an ultrafine grain structure in low carbon steels with a wide range of hardenability. This included warm deformation of supercooled austenite followed by reheating in the austenite region and cooling (RHA). The ultrafine ferrite structure was independent of steel composition. However, the mechanism of ferrite refinement changed with the steel quench hardenability. In a relatively low hardenable steel, the ultrafine structure was produced through dynamic strain induced transformation, whereas the ferrite refinement was formed by static transformation in steels with high quench hardenability. The use of a model Ni-30Fe austenitic alloy revealed that the deformation temperature has a strong effect on the nature of the intragranular defects. There was a transition temperature below which the cell dislocation structure changed to laminar microbands. It appears that the extreme refinement of ferrite is due to the formation of extensive high angle intragranular defects at these low deformation temperature that then act as sites for static transformation. © 2008 World Scientific Publishing Company.

Preparation and structural characterization of vulcanized natural rubber nanocomposites containing nickel-zinc ferrite nanopowders

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

X-ray diffraction and mossbauer spectra of nickel ferrite prepared by combustion reaction

Nickel ferrite powders with a nominal NiFe2O4 composition were synthesized by combustion reaction using urea as fuel. The powder was obtained using a vitreous silica basin heated directly on a hot plate at 480 degrees C until self-ignition occurred. After combustion, the powder was calcined at 700 degrees C for 2 h. The formation of the spinel phase and the distribution of cations in the tetrahedral and octahedral sites of the crystal structure were investigated by the Rietveld method, using synchrotron X-ray diffraction data and Mossbauer spectroscopy. The material presented a crystallite size of 120 nm and magnetic properties. The resulting stoichiometry after the Rietveld refinement was (Fe-0.989(2) Ni-0.011(2)) [Fe-1.012(2) Ni-0.989(2)] O-4.

Microwave-hydrothermal synthesis of perovskite bismuth ferrite nanoparticles

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effect of annealing atmosphere on phase formation and electrical characteristics of bismuth ferrite thin films

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Piezoresponse behavior of niobium doped bismuth ferrite thin films grown by chemical method

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Quantum chemical modeling of perovskite: An investigation of piezoelectricity in ferrite of yttrium

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Piezoelectric behavior of SrRuO(3) buffered lanthanum modified bismuth ferrite thin films grown by chemical method

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Slurry sample injection for determination of ferrite nanocolloids chemical composition by ICP spectrometry

This work proposes a new method to determine the chemical composition of magnetic ferrite nanoparticles by the slurry injection technique using the inductively coupled plasma optical emission spectroscopy. In this way, experimental conditions such as aerosol gas flow rate and colloidal stability were optimized in order to use aqueous calibration curves in the slurry nebulization and to determine the chemical composition of a series of sols containing chemically synthesized size-tailored NiFe 2O 4 nanograms. Then, the results of direct sampling and those of conventional aqueous introduction analysis are compared, showing the efficiency of the proposed method.

Magnetoelectric coefficient in strontium ruthenate buffered lanthanum modified bismuth ferrite thin films grown by chemical method

This paper focuses on the magnetoelectric coupling (ME) at room temperature in lanthanum modified bismuth ferrite thin film (BLFO) deposited on SrRuO 3-buffered Pt/TiO 2/SiO 2/Si(100) substrates by the soft chemical method. BLFO film was coherently grown at a temperature of 500 °C. The magnetoelectric coefficient measurement was performed to evidence magnetoelectric coupling behavior. Room temperature magnetic coercive field indicates that the film is magnetically soft. The maximum magnetoelectric coefficient in the longitudinal direction was close to 12 V/cmOe. Dielectric permittivity and dielectric loss demonstrated only slight dispersion with frequency due the less two-dimensional stress in the plane of the film. Polarization reversal was investigated by applying dc voltage through a conductive tip during the area scanning. We observed that various types of domain behavior such as 71 ° and 180° domain switching, and pinned domain formation occurred. Copyright © 2009 American Scientific Publishers All rights reserved.