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The current work involves the use of flash auto combustion procedure to synthesize nano-ferrites Mn0.6Zn0.4LaxFe2-xO4, (x = 0.00, 0.02, 0.04, 0.06, 0.08, and 0.10) annealing at 500 °C for 4 h. X-ray Diffraction (XRD), Fourier transition infrared spectroscopy (FTIR), and high-resolution transmission electron microscopy (HRTEM) were used to characterize the structural properties of produced samples. Scanning electron microscopy (SEM) was utilized to examine the surface morphology of the samples at various Lanthanum concentrations. From XRD, the spinel cubic structure for all samples with few traces of secondary phase at high La concentrations is assured. The crystallite size is estimated to be in the nanoscale range of 13.16–18.13 nm using the Debye–Scherrer formula. The appearance of characteristic vibrational bands near 460 cm−1 and 563 cm−1, which correspond to the octahedral and tetrahedral sites, respectively, confirms the formation of the spinel structure. SEM micrographs show that the grains are nearly irregular in shape, and the accumulation of La+3 ions at the grain boundaries exerts tensile strength and pressure on the grain itself, reducing the grain size. The particle size estimated by TEM coincides well with the crystallite size determined by XRD. The thermogravimetric analysis, (TGA), was used to investigate the thermal properties of the nanoferrites from room temperature to 1000 °C. In comparison to the other samples, the sample with x = 0.04 has greater thermal stability and the TEM measurement indicates that this sample has the smallest particle size. Therefore, we can assert that the thermal stability improves as the particle size decreases. The magnetic permeability was measured in the temperature range 303–773 K at a fixed frequency of 10 kHz and at various La contents. The sample with x = 0.04 has a minimal permeability value, showing that the separation brought on by La ions has diminished the super exchange contact between magnetic ions. [ABSTRACT FROM AUTHOR]

The current work involves the use of flash auto combustion procedure to synthesize nano-ferrites Mn0.6Zn0.4LaxFe2-xO4, (x = 0.00, 0.02, 0.04, 0.06, 0.08, and 0.10) annealing at 500 °C for 4 h. X-ray Diffraction (XRD), Fourier transition infrared spectroscopy (FTIR), and high-resolution transmission electron microscopy (HRTEM) were used to characterize the structural properties of produced samples. Scanning electron microscopy (SEM) was utilized to examine the surface morphology of the samples at various Lanthanum concentrations. From XRD, the spinel cubic structure for all samples with few traces of secondary phase at high La concentrations is assured. The crystallite size is estimated to be in the nanoscale range of 13.16–18.13 nm using the Debye–Scherrer formula. The appearance of characteristic vibrational bands near 460 cm−1 and 563 cm−1, which correspond to the octahedral and tetrahedral sites, respectively, confirms the formation of the spinel structure. SEM micrographs show that the grains are nearly irregular in shape, and the accumulation of La+3 ions at the grain boundaries exerts tensile strength and pressure on the grain itself, reducing the grain size. The particle size estimated by TEM coincides well with the crystallite size determined by XRD. The thermogravimetric analysis, (TGA), was used to investigate the thermal properties of the nanoferrites from room temperature to 1000 °C. In comparison to the other samples, the sample with x = 0.04 has greater thermal stability and the TEM measurement indicates that this sample has the smallest particle size. Therefore, we can assert that the thermal stability improves as the particle size decreases. The magnetic permeability was measured in the temperature range 303–773 K at a fixed frequency of 10 kHz and at various La contents. The sample with x = 0.04 has a minimal permeability value, showing that the separation brought on by La ions has diminished the super exchange contact between magnetic ions. [ABSTRACT FROM AUTHOR]

Superlattice films composed of frustrated spin systems, [ZnFe2O4]m/[ZnCr2O4]m, are grown on MgAl2O4 (111) substrates by pulsed laser deposition, and their frustrated magnetism is studied. The superlattice films show spin-glass behavior and the spin-glass transition temperature (Tg) varies nonmonotonically as a function of the layer thickness m. Tg increases with decreasing m due to an increase in the inhomogeneous exchange interaction between Cr3+ and Fe3+ at the interface. However, below m = 4, a decrease in Tg is observed. Compared with the solid solution Zn(CrFe)O4 film and the other superlattices, the decrease in Tg is considered to be a unique property of the periodically modulated short period superlattices. [ABSTRACT FROM AUTHOR]

For the industrial preparation of MnZn ferrite with high magnetic permeability and low magnetic loss, three-phase asynchronous machine was used to extrude MnZn ferrite magnet with large aspect ratio, and the final high-performance MnZn ferrite was obtained via subsequent tube furnace high-temperature sintering method. The effects of sintering temperature and oxygen partial pressure on the evolution of microstructure, and the electromagnetic and thermal properties for the MnZn ferrites were discussed systematically. The results showed that with the increase of the sintering temperature and oxygen partial pressure, both the effective permeability and quality factor show a trend of first increasing and then decreasing, and the highest values of them were obtained when the sintering temperature and oxygen partial pressure were 1260 °C and 3% oxygen partial pressure, respectively. The thermal conductivity exhibited a parabolic shaped trend with the increase of the oxygen partial pressure, and achieved maximum value at 3% oxygen partial pressure, while it decreased as the temperature increases further. The total magnetic loss of MnZn ferrite had a valley bottom temperature. As the oxygen partial pressure increased, the valley bottom temperature shifted to a higher temperature. The MnZn ferrite prepared with 3% oxygen partial pressure had the lowest total loss at 90 °C. [ABSTRACT FROM AUTHOR]

This contribution focuses on the use of modified Rayleigh law as a technique for determining the intrinsic and extrinsic (reversible/irreversible) contributions to the piezoelectric effect up to 150 °C across a broad compositional space, augmenting previous understanding of the BiFeO3-(K0.5Bi0.5)TiO3-PbTiO3 system. At room temperature, a mechanistic explanation of the correlation between crystal symmetry, i.e., tetragonal spontaneous strain, xs, and the Rayleigh relations using Landau theory is provided. The intrinsic response was found to be heavily dependent upon the tetragonal xs, whereby an optimisation between polarization and permittivity was elucidated, leading to enhanced piezoelectric charge coefficients. A c/a ratio of ~1.041 was identified at which the room temperature intrinsic and extrinsic effects were at a maximum; a dinit of 183 x 10-12 m/V and Rayleigh coefficient of 59 x 10-18 m²/V² were measured, resulting in the largest piezoelectric charge coefficients. The piezoelectric charge coefficient d33, intrinsic and extrinsic contributions of these materials were all found to increase up to 150 °C while adhering to the Rayleigh model. The reversible extrinsic component of the total reversible response, dinit, was calculated to be relatively minor, 4.9% at room temperature, increasing to 12.1% at 150 °C, signifying its increasing influence to the piezoelectric effect, as domain wall motion is thermally activated. Hence, the phenomenological interpretation provided here may be used as a roadmap to elucidate the origins of the temperature dependence of the piezoelectric effect. [ABSTRACT FROM AUTHOR]

This study presents the effects of substitution of Zn2+ for Co2+ at low concentrations and the effects of temperature variations on the structural, magnetic, and magnetostrictive properties of cobalt ferrite. Although the Zn-substituted cobalt ferrite samples, Co1-xZnxFe2O4 (x = 0.02, 0.04, 0.06, 0.09, and 0.17) did not show observable changes in crystal structure, the magnetic and magnetostrictive properties were strongly affected. The variation in magnetic susceptibility with composition can be related to the variations in magnetization, coercive field and magnetocrystalline anisotropy. The changes in coercive field were found to be primarily due to the variations in the magnetocrystalline anisotropy. The effect of magnetocrystalline anisotropy on magnetization was stronger at lower cation concentration than at higher concentrations. The decrease in magnetization around 150 K is attributed to the high magnetocrystalline anisotropy at low temperatures which prevented the maximum applied field of 4 MA/m from causing the saturation of magnetization in the samples. Because the magnetocrystalline anisotropy was determined with the magnetization data using the Law of Approach to saturation magnetization, the reliability of the result was found to decrease with decrease in temperature. Peak-to-peak magnetostriction amplitude and the strain sensitivity decreased with increase in Zn substitution. [ABSTRACT FROM AUTHOR]

Integrate Zinc substituted cobalt ferrites have incorporated by the Co-precipitation technique. The XRD pattern shows the formation and microstructure evolutions of nanocomposites. Cationic coordination, exchange interactions raised between the tetrahedral site in high frequency and octahedral site in the lower frequency described FTIR results. The SEM images showed that the spongy morphology with PVP matrix and fewer agglomerated grains. It exposes the grains and the range of grains recovered from 1μ to 400 nm, which is in compromise with the test of grain size of XRD. VSM study reveals that the magnetization of substances raises by incrementing the non-magnetic (Zn) material incorporated cobalt ferrite. EPR confirmed that synthesized materials exhibited ferromagnetic properties from Lande g-factor. TGA/DSC curve reports the weight loss and heat flow by endothermic absorption through exothermic emission in the ferrite. It used these materials for the potential effort like magneto-optical recording media and magnetic sensors. [ABSTRACT FROM AUTHOR]

Static and dynamic magnetic properties of oleic acid/oleyamine coated Mn–Zn ferrite nanoparticles of diameter 82 Å are reported. The zero-field-cooled peak temperature decreases with increasing magnetic field and obeys the well known de Almeida–Thouless line. The zero-field-cooled magnetization data are simulated by assuming noninteracting magnetic particles with uniaxial anisotropy and lognormal particle size distribution. The relevant parameters give the values of particle diameter (D) 80 Å, standard deviation 0.3 in ln(D), and the anisotropy constant K to be 5.8×105 erg/cm3. The observed higher value of standard deviation is due to the interparticle interaction. The complex magnetic susceptibility was measured as a function of temperature for frequencies ranging from 67 to 1800 Hz. The temperature at which the maximum in the ac-susceptibility curve is observed is well accounted by the Vogel–Fulcher law for both χ′ and χ″. The peak is also observed in a plot of χ″/χ′ versus temperature, which may mean the existence of magnetic aftereffect, and furthermore, it has an Arrhenius as well as Vogel–Fulcher law type dependence. An observed nonthermal activation type relaxation mechanism at 12 K is attributed to possible quantum tunneling effect in Mn–Zn ferrite nanoparticles. [ABSTRACT FROM AUTHOR]

We have observed the exchange spring behavior in the soft (Fe3O4)-hard (BaCa2Fe16O27)-ferrite composite by tailoring the particle size of the individual phases and by suitable thermal treatment of the composite. The magnetization curve for the nanocomposite heated at 800 °C shows a single loop hysteresis showing the existence of the exchange spring phenomena in the composite and an enhancement of 13% in (BH)max compared to the parent hard ferrite (BaCa2Fe16O27). The Henkel plot provides the proof of the presence of the exchange interaction between the soft and hard grains as well as its dominance over the dipolar interaction in the nanocomposite. [ABSTRACT FROM AUTHOR]

The microstructure and corrosion resistance evolution of 316 L heat-affected zone were studied by simulated welding thermal technology. The different thermal simulation parameters affected the ferrite content and grain boundary characteristics. The ferrite content and grain boundary characteristics in thermal simulation samples were studied by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). Combining the electrochemical test, it was observed that the Cr-depleted zone existed at the austenite/ferrite interface and the high angle grain boundary (HAGB) of the austenite interface usually became the nucleation point of pitting corrosion. • Retained ferrite can be found due to chromium aggregation during welding thermal cycle. • Cr-depleted zone and random high angle grain boundary are conducive to pitting nucleation. • Corrosion extends from ferrite/austenite phase boundary to austenite matrix. [ABSTRACT FROM AUTHOR]

Provides information on a study which presented the variation of the ferrimagnetic resonance linewidth with temperature in both single and polycrystalline manganese ferrites. Sample preparation; Measurement system; Results and discussion.

In the present work, spinel ferrite T 0.35 Zn 0.55 Cu 0.1 Fe 2 O 4 (T = Mn, Ni) nanoparticles have been synthesized via the sol-gel method. We have used the X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) to investigate structural properties. Thermal stability of the samples was checked by Thermo-gravimetric and Differential thermal analysis (TG-DTA). The surface morphology and the shape of the particles were demonstrated by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The XRD patterns confirm the formation of the single-phase polycrystalline cubic spinel structure with Fd-3m space group. The average crystallite size evaluated from XRD data is found to be 13.7 nm and 15.6 nm which is consistent with the results of particle size estimated from TEM. The DC resistivity evaluated through the two-probe measurement, lowering of resistivity with a rise in temperature providing the traditional semiconducting behavior of spinel ferrites. The dielectric parameters such as dielectric constant ( ε ' ), ac conductivity ( σ a c ), and dielectric loss (t a n δ) are investigated as a function of frequency and temperature. The results of dielectric measurement revealed a general dielectric dispersion due to the Maxwell-Wagner type of interfacial polarization and the hopping of charge carriers between Fe2+ and Fe3+ ions. The prepared samples exhibit low dielectric loss and high resistivity which make them suitable for high frequency microwave and power transform applications. • T0.35Zn0.55Cu0.1Fe2O4 (T = Mn, Ni) ferrite nanoparticles have been successfully synthesized by sol-gel method. • Structural analysis was carried out using X-ray diffraction and TEM to identify pure ferrite phases. • The variation of DC electrical resistivity of ferrite nanoparticles follows well known Arrhenius equation. • The frequency and temperature dependent dielectric properties were investigated. [ABSTRACT FROM AUTHOR]

The superconductor YBa2Cu3O7-δ (Y123) is prepared by the solid-state route, while the nanosized Ni0.5Zn0.5Fe2O4 (Ni-Zn ferrite) is synthesized via citric acid sol-gel technique. The composite material of the type (Ni0.5Zn0.5Fe2O4)x/YBa2Cu3O7-δ, where x = 0.00, 0.03, 0.10, and 0.50 wt%, is prepared by a modified solid-state method to study the effect of doping Ni-Zn nanosized ferrite on the superconducting, structure, and thermal properties of Y123. The prepared samples show Meissner effect which confirmed the presence of superconducting phase at liquid nitrogen temperature (77 K). The prepared samples have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersion of X-ray (EDX), infra-red (IR) spectroscopy, thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), DC resistance by four-probe, and critical current density measurements. It was found that by increasing Ni0.5Zn0.5Fe2O4 nanoparticles in the Y123 compound, the unit cell volume of the orthorhombic phase decreases, but the transition temperature Tc and critical current density Jc decrease for low doping (x = 0.03 wt%) then increase (x = 0.10 and 0.50 wt%) for Ni0.5Zn0.5Fe2O4 doped in Y123. The transport properties of the (Ni0.5Zn0.5Fe2O4)x/YBa2Cu3O7-δ composite as electrical resistance R, Tc, and Jc are interpreted according to Bean's critical state model and charge-vortex interaction combined with vortex pinning in Y123 high-Tc mixed-state type-II superconductor. Highlights: The critical current density Jc decreased for low doping of nanosized Ni-Zn ferrite into Y123 with ratio of 0.03 wt% and increased by increasing doping ratio to 0.50 wt%. The physical properties are improved by the coexistence of the superconductor Y123 and nanosized Ni-Zn ferrites in nanocomposite material. [ABSTRACT FROM AUTHOR]

In this research, an experimental evaluation is conducted on the hydrothermal behavior of water-based manganese ferrite nanofluid flowing in a metal foam tube. For this purpose, manganese ferrite nanoparticles are synthesized, and X-ray diffraction and scanning electron microscopy are implemented to specify the samples for determination of phase and size of nanoparticles. The effects of Reynolds number, Prandtl number, and presence of MnFe2O4 nanoparticles inside the water on the Nusselt number and friction factor have been studied. The experimental analysis shows that the increment of Reynolds number, Prandtl number, and nanoparticles concentration improve the heat transfer performance. The maximum of 19.1% and 10.5% increase in Nusselt number and friction factor have been achieved respectively by dispersion of 2 wt% manganese ferrite nanoparticles inside the deionized water at Reynolds number of 1,000. A hydrothermal index is proposed to consider the thermal and hydrodynamic characteristics of the nanofluid, and it is attained that the convection heat transfer improvement dominates the pressure drop in this work. According to the experimental results, the Nusselt number and friction factor of the nanofluid is modeled as a function of Reynolds number, Prandtl number, and nanoparticles concentration using artificial neural network with an acceptable precision. [ABSTRACT FROM AUTHOR]

The crystal structure and surface morphology of ceramics as well dielectric and thermal properties of Bi1−xErxFeO3 (where x = 0.05 − 0.20, Δх = 0.05) magnetoelectric solid solutions (SS) were investigated. The regularities of changes in phase composition, microstructure, electrical and dielectric properties of objects at room temperature are established. [ABSTRACT FROM AUTHOR]

A low-loss Mn0.7Zn0.24Fe2.06O4 ferrite has been prepared by a solid-state reaction method. The MnZn ferrite has a high initial permeability, μi (3097), a high saturation induction, Bs (526 mT), a high Curie temperature, Tc (220 °C), and a low core loss, PL (≤ 415 kW/m3) in a wide temperature (25-120 °C) and frequency (10-100 kHz) range. As the temperature increases, an initial decrease followed by a subsequent increase of hysteresis loss, Ph, and eddy current loss, Pe is observed. Both Ph and Pe increase with increasing frequency. When f ≥ 300 kHz, a residual loss, Pr, appears. Pe increases with increasing temperature and frequency. The temperature and frequency dependence of Ph can be explained by irreversible domain wall movements, Pe by the skin effect, and Pr by domain wall resonance, respectively. [ABSTRACT FROM AUTHOR]

BaFe 12-x Ti x O 19 (x = 0.5, 1, 2) solid solutions were synthesized by solid state reaction at 1350 °C for pure BaFe 12 O 19 and 1400 °C for Ti-substituted samples for 3 h in the air. The phase purity of the final products was verified by X-ray diffraction. The decrease of Curie temperature of the solid solutions from 450 to 240 °C was induced by x changes from 0 to 2. The electromagnetic parameters of the BaFe 12-x Ti x O 19 (x = 0.5, 1, 2) ferrites were measured in the frequency range of 8–12 GHz using the transmission line method. [ABSTRACT FROM AUTHOR]

Effect of Zn site-selected doping on electrical properties, high-temperature stability and sensitivity of piezoelectric response for BiFeO 3 -BaTiO 3 ceramics was investigated. The results revealed that the addition of Zn leaded to an evident modification of the microstructure. The B-site selected doping was a more effective approach in improving piezoelectric properties as well as their thermal stability than those of A-site selected doping. Moreover, the enhanced piezoelectric properties accompanying by excellent high-temperature stability and sensitivity in B-site selected doping ceramics were obtained. The microstructure, domain switching behavior and temperature-dependent piezoelectric response in Zn site-selected doping ceramics were investigated, and their relationships with improving piezoelectric properties and high-temperature stability were explored. These results showed that the B-site selected doping ceramics had excellent piezoelectric properties ( d 33 = 192pC/N) along with a high-temperature stability ( T d = 450 °C). [ABSTRACT FROM AUTHOR]

The effect of variation in composition on the structural, magnetic, optical and photo catalytic activity of magnesium ferrite (MgFe 2 O 4 ) -graphene oxide (GO) nanocomposites was studied. Magnetic nanocomposites of GO and MgFe 2 O 4 nanoparticles (NPs) with varying w/w ratio were synthesized by facile sonication method. X-Ray diffraction patterns confirmed the presence of spinel ferrite phase in the nanocomposites with the crystalline size 8–32 nm. Fourier transformation infrared (FT-IR) spectra of the nanocomposites displayed absorption bands corresponding to GO and MgFe 2 O 4 NPs along with red shift of bands corresponding to C=O, C=C and O-H stretching. Thermo gravimetric analysis confirmed higher stability of nanocomposites over pristine GO. Saturation magnetization increased from 3.63 to 11.10 emu/g with the increase in content of MgFe 2 O 4 NPs in the nanocomposites. Scanning electron microscopy analysis along with energy dispersive spectroscopy (SEM-EDX) confirmed the presence of MgFe 2 O 4 NPs along with GO sheets. Immobilization of clusters of MgFe 2 O 4 NPs onto GO sheets was evident from transmission electron micrographs (TEM) of all the nanocomposites. BET surface area of the nanocomposites ranged from 63.04 to 165.29 m 2 /g and was maximum when GO:MgFe 2 O 4 w/w ratio was 1:0.5. It was markedly higher than pristine GO and MgFe 2 O 4 NPs. Optical studies revealed lowering of the band gap in the nanocomposites upto 2.21 eV as compared to pristine MgFe 2 O 4 NPs. Photoluminescence (PL) spectra of nanocomposites displayed quenching of PL intensity with increase of GO content. Band gap also displayed similar trend. The synthesized nanocomposites were used as photocatalysts for methylene blue dye degradation under visible light irradiation. The nanocomposite with GO to MgFe 2 O 4 ratio 1:0.5 displayed best activity with complete degradation of dye in 30 min. The results confirmed that the composition of GO based magnetic nanocomposites can be tailored for efficient removal of contaminants. [ABSTRACT FROM AUTHOR]

A low-temperature co-fired In 3+ ion doped Mg-Cd ferrite (Mg 0.8 Cd 0.2 Fe 2−x In x O 4 with 0 ≤ x ≤ 0.15) with a 3 wt% Bi 2 O 3 additive was synthesized using a solid-state reaction method. X-ray diffraction reveals that the samples contain both a spinel ferrite phase and a CdIn 2 O 4 dielectric phase. Following In 3+ ion doping, the saturation magnetization increases first but then decreases. Coercivity, on the other hand, decreases first before it increases. The combined effects of In doping together with the addition of Bi 2 O 3 endowed the compound materials with excellent magnetic permeability and dielectric permittivity. Using 3 wt% Bi 2 O 3 , the magnetic permeability increases first from 16 to 26.5, and then decreases to 15.6, while the dielectric permittivity increases from 19 to 32. The equivalent permeability and permittivity appears when x = 0.10. The real parts of both permeability and permittivity are about 26, and the material had low loss-tangents (both magnetic and dielectric). This indicates that this ferrite is an excellent material to be used in miniature antennas. [ABSTRACT FROM AUTHOR]

We report the composition dependent elastic and thermal properties of Li Zn ferrite (Li 0.5-x/2 Zn x Fe 2.5-x/2 O 4 , x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) ceramics. The IR absorption frequencies (obtained from the Fourier transform infrared spectra), the lattice parameters and the mass-densities were used to evaluate the elastic and thermal parameters such as force constant, elastic moduli and Debye temperature of the studied Li Zn ferrite samples as a function of Zn-content x. The observed force constants were low in value for the octahedral site complexes than that of the tetrahedral site complexes, but both the force constants were increasing with increasing Zn content. The longitudinal elastic wave velocities in the sample were higher than the transverse wave velocities. The elastic moduli such as Young's modulus ( E ), bulk modulus ( B ) and rigidity modulus ( G ) showed increasing trends with Zn concentration in the samples. The calculated Debye temperature ( θ D ) is near to the literature values obtained experimentally. Our results provide a better understanding of the variation of mechanical, elastic and thermal properties of Li Zn ferrites. [ABSTRACT FROM AUTHOR]

Presents information on a study which measured the thermal expansion of titanium-substituted barium hexaferrite single crystals. Anisotropic behavior of magnetoplumbite hexaferrites.

The propagation of high-intensity ultrasonic vibration into weld pool can influence on microstructure and mechanical properties of welded joints. This research introduced a hybrid method for improving weld quality by using superimposed ultrasonic vibration on workpiece directly in underwater flux cored arc welding (FCAW). With the purpose of revealing how macrostructure, microstructure and mechanical properties of welded joints are affected by ultrasonic vibration within the weld metal, the present study has been carried out. The results indicated that proeutectoid ferrite, ferrite side plate and acicular ferrite constitute the microstructures of weld metal. Ultrasonic vibration can affect the size and morphology of prior austenite grain during weld pool solidification and eventually accelerate the formation of fine ferrite microstructure of weld metal in high proportion in the subsequently solid-state phase transformation. Excellent balance of high tensile strength and impact toughness is realized as more fine columnar microstructures in weld metal with using ultrasonic vibration. These findings suggest that the addition of ultrasonic vibration is an effective way to improve the tensile strength and impact toughness of weld metal during underwater wet welding. [ABSTRACT FROM AUTHOR]

Magneto polymer matrix composites (MPMC) is a new class of magnetic polymer materials which are being developed and under investigation as potential materials for tomorrow’s aircraft structures. It encompasses magnetic, particulate strengthening (dispersion strengthening) as well as fiber reinforcement/strengthening characteristics which are sought out to be utilized toward making efficient future aerospace composite materials. Various types of ferrites including barium, cobalt, iron, and strontium were explored for being used in making new composites. Here a comprehensive review of the synthesis, structure, properties, thermodynamics, surface chemistry, and phase transformations of individual ferrites and clusters of ferrites as fillers is presented. In particular a discussion about the rational control of the mechanical, physical, thermal, electrical, and magnetic properties of magneto polymer matrix composites through surface functionalization, modification, emulsification/compounding/blending, heat treatment (phase transformation and separation), and control of processing conditions (temperature, pressure and geometry of mold) is provided. These smart materials have a wide range of potential applications in medicine, drug delivery, bio imaging, bio marking, tissue engineering, electromagnetic interference (EMI) and electromagnetic force (EMF) shielding, and as competent materials for aerospace structural applications. [ABSTRACT FROM PUBLISHER]

Terbium (Tb) and dysprosium (Dy) doped lithium-nickel nano-sized ferrites (Li 0.2 Ni 0.8 Tb 0.5 x Dy 0.5 x Fe 2− x O 4 where x =0.00−0.08) were prepared by micro-emulsion technique. The X-ray diffraction (XRD) patterns confirmed the single phase cubic spinel structure. The lattice constant was increased due to larger ionic radii of Tb 3+ and Dy 3+ cations. The crystallite size was found in the range 30–42 nm. The FTIR (Fourier transform infrared spectroscopy) spectra revealed two significant absorption bands (~400–600 cm −1 ) which indicate the formation of cubic spinel structure. The peaking behavior of dielectric parameters was observed beyond 1.5 GHz. The dielectric constant and dielectric loss were found to decrease by the increase of Tb–Dy contents and frequency. The doping of Tb and Dy in Li–Ni ferrites led to increase the coercive field (120–156 Oe). The smaller magnetic and dielectric parameters suggested the possible utility of these nano-materials in switching and microwave devices applications. [ABSTRACT FROM AUTHOR]

Several composites and nanocomposites based on a polymeric matrix and ceramic fillers are being pursued for use as multifunctional and innovative materials. Nevertheless, there is a series of challenges to be solved in this area such as the understanding of the role of interfaces and the synergy between matrix and fillers. In this work, vulcanized natural rubber nanocomposites were prepared with different concentrations of two kinds of ceramic nanoparticles, potassium strontium niobate (KSrNbO or KSN) and nickel-zinc ferrite (NiZnFeO or NZF), synthesized by a chemical method known as the modified polyol method. Morphological and thermal characterizations were carried out by AFM, TG/DTG, TG/FTIR and DSC. The thermal properties of nanocomposites were compared and discussed as functions of concentration, type and surface of nanoparticles. The results obtained suggest that the base concentration for both types of nanoparticles inside the polymer matrix volume greatly adds to the increase in thermal stability up to 11 % and the glass transition temperature up to 10 °C. A similar evolution for the glass transition temperature ( T ), thermal stability temperature ( T ) and dielectric permittivity ( ε′) was identified, suggesting that these phenomena are mainly dominated by the same mechanisms. These results point to the possibility for the thermal parameter modulation in magnetic and ferroelectric nanocomposites by means of a suitable control of concentration and properties of the KSN and NZF nanoparticles. [ABSTRACT FROM AUTHOR]

As is well known, the metallurgical microstructure of carbon steel is formed by ferrite and pearlite after the annealing heat treatment. When the cooling rate increases, the diffusive process is interrupted causing a change in the metallurgical microstructure which will affect steel properties. The aim of this work was to study thermal, structural, and microstructural properties of annealed carbon steel samples with four different carbon contents. Crystalline structure and crystalline quality were studied by the X-ray diffraction technique, where the full width at half maximum analysis showed that as the carbon content increased, the crystalline quality decreased. The metallurgical microstructure morphology was studied by scanning electron microscopy. The thermal diffusivity and the heat capacity were determined by the photoacoustic technique and by the thermal relaxation method, respectively. The thermal diffusivity and the thermal conductivity decreased as the carbon content increased. The amplitude signal of photothermal radiometry increased as the carbon content increased, while the phase signal of photothermal radiometry did not show significant differences among studied carbon steel types. The photoacoustic technique represents an important alternative in the steel characterization field. [ABSTRACT FROM AUTHOR]

• CTAB assisted synthesis of Ni 0.5 Zn 0.5 Fe 2 O 4 /rGO nano hybrid by sol–gel auto-combustion. • Super paramagnetic relaxation as well as presence of two ordered magnetic sites. • Evolution of one doublet and two sextets in the hyperfine spectra. • Enhanced surface spin disorder: enhancement in coercivity. Ni 0.5 Zn 0.5 Fe 2 O 4 (NZ)/reduced graphene oxide (rGO) nanohybrids were prepared by surfactant assisted citric acid mediated sol–gel auto combustion method. Samples were analyzed by various characterization techniques to acquire information about the structural, morphological, thermal and magnetic properties. X-ray diffraction results confirm the successful synthesis of NZ/rGO nanocomposite. Transmission electron microscopic images reveal that the NZ nanostructures are well decorated on the rGO matrix. Few of them are also sandwiched within the rGO sheets. Samples were thermally characterized by thermo-gravimetric setup. Raman spectroscopic technique was also employed for the analysis of the samples. The room temperature Mössbauer spectra of the samples were fitted into a doublet and two sextets owing to the presence of two magnetic sites. Room temperature (300 K), as well as low temperature (10 K) M−H loops of the samples were recorded by SQUID magnetometer. Enhancement in the value of coercivity of the NZ/rGO sample with comparison to the pure NZ, has established that the incorporation of rGO has effectively influenced the magnetic property of pure NZ. [ABSTRACT FROM AUTHOR]

Thermal aging and consequent embrittlement of materials are ongoing issues in cast stainless steels, as well as duplex, and high-Cr ferritic stainless steels. Spinodal decomposition is largely responsible for the well-known '748 K (475 °C) embrittlement' that results in drastic reductions in ductility and toughness in these materials. This process is also operative in welds of either cast or wrought stainless steels where δ-ferrite is present. While the embrittlement can occur after several hundred hours of aging at 748 K (475 °C), the process is also operative at lower temperatures, at the 561 K (288 °C) operating temperature of a boiling water reactor (BWR), for example, where ductility reductions have been observed after several tens of thousands of hours of exposure. An experimental program was carried out in order to understand how spinodal decomposition may affect changes in material properties in Type 316L BWR piping weld metals. The study included material characterization, nanoindentation hardness, double-loop electrochemical potentiokinetic reactivation (DL-EPR), Charpy-V, tensile, SCC crack growth, and in situ fracture toughness testing as a function of δ-ferrite content, aging time, and temperature. SCC crack growth rates of Type 316L stainless steel weld metal under simulated BWR conditions showed an approximate 2 times increase in crack growth rate over that of the unaged as-welded material. In situ fracture toughness measurements indicate that environmental exposure can result in a reduction of toughness by up to 40 pct over the corresponding at-temperature air-tested values. Material characterization results suggest that spinodal decomposition is responsible for the degradation of material properties measured in air, and that degradation of the in situ properties may be a result of hydrogen absorbed during exposure to the high-temperature water environment. [ABSTRACT FROM AUTHOR]

Magnetorheological behavior of micro magnetic particle dispersed in silicone oil has been characterized by a multiplied form of phenomenological models taking the effect of shear rate, powder volume fraction, temperature and magnetic flux density. Magnetorheological fluid samples with seven different particle volume fraction were prepared by adding ferrite particles in silicone base oil and their shear viscosity of fluid samples were measured under three different temperatures (40 °C, 70 °C, and 110 °C) and ten different magnetic flux density (0–100 mT). The fluid had an upper limit to the increase of viscosity under the effect of external magnetic field and the saturation values were dependent on the operating temperature, shear rate and volume fraction of magnetic powder. The rheological behaviors have been characterized by our developed model which can be very useful for the precise control of the magnetorheological fluid. [ABSTRACT FROM AUTHOR]

The effects of sintering temperature on microstructure, phase, electrical and magnetic properties of LiZn ferrites prepared by hot pressing methods were examined systematically. All the ferrites were spinel strustures sintered at the temperature above 1050°C. At higher than 1100°C, pores within the grains appeared due to the volatilization of lithium. The DC electrical resistivity ρ increased firstly and decreased dramatically because of the Fe2+formation. The magnetic properties showed that the saturation magnetization (Ms) increased and coercive field (Hc) decreased with the increasing temperature. The hot pressing method is proven an effective way to obtain the densified LiZn ferrites. [ABSTRACT FROM AUTHOR]

Novel superparamagnetic nanocomposites based on covalently linked waterborne polyurethane (WPU) and Ni 0.3 Zn 0.7 Fe 2 O 4 ferrite nanospheres (NZFO) were successfully synthesized using an in situ polymerization method. The Ni 0.3 Zn 0.7 Fe 2 O 4 nanoparticles prepared by a typical solvothermal method were modified with 3-(triethoxysilyl) propyl isocyanate (IPTS) to improve the compatibility with monomers. The functionalized NZFO nanoparticles (NZFO-IPTS) served as effective cross-link points and reacted with the WPU matrix, forming chemical bonds. It was found that the NZFO-IPTS greatly improved the dispersibility of NZFO nanoparticles in the WPU matrix, and the introduction of NZFO-IPTS enhanced the thermal behavior and mechanical properties of the WPU polymer. What's more, the WPU/NZFO nanocomposites presented superior magnetic properties and a maximum saturation magnetization (Ms) of 16.58 emu/cm 3 was observed, thus illustrating the potential applications of the generated materials in microwave-absorbing fields. [ABSTRACT FROM AUTHOR]

To enable the life extension of Light Water Reactors (LWRs) beyond 60 years, it is critical to gain adequate knowledge for making conclusive predictions to assure the integrity of duplex stainless steel reactor components, e.g. primary pressure boundary and reactor vessel internal. Microstructural changes in the ferrite of thermally aged, neutron irradiated only, and neutron irradiated after being thermally aged cast austenitic stainless steels (CASS) were investigated using atom probe tomography. The thermal aging was performed at 400 °C for 10,000 h and the irradiation was conducted in the Halden reactor at ∼315 °C to 0.08 dpa (5.6 × 10 19 n/cm 2 , E > 1 MeV). Low dose neutron irradiation at a dose rate of 5 × 10 −9 dpa/s was found to induce spinodal decomposition in the ferrite of as-cast microstructure, and further to enhance the spinodal decomposition in the thermally aged cast alloys. Regarding the G-phase precipitates, the neutron irradiation dramatically increases the precipitate size, and alters the composition of the precipitates with increased, Mn, Ni, Si and Mo and reduced Fe and Cr contents. The results have shown that low dose neutron irradiation can further accelerate the degradation of ferrite in a duplex stainless steel at the LWR relevant condition. [ABSTRACT FROM AUTHOR]

Nanoparticles of $$\hbox {Ni}_{0.5}\hbox {Zn}_{0.5}\hbox {Fe}_{2}\hbox {O}_{4}$$ have been prepared by the co-precipitation method, and X-ray diffraction analysis has confirmed the formation of the desired ferrite. A pure epoxy sample and three samples of $$\hbox {epoxy/Ni}_{0.5}\hbox {Zn}_{0.5}\hbox {Fe}_{2}\hbox {O}_{4}$$ composites have also been prepared with different ferrite percentages. These samples have been characterized by Fourier transform infrared spectroscopy. The magnetization of the composites has been investigated by using a vibrating sample magnetometer and has revealed that these composites may be promising candidates for electromagnetic interference suppression. Moreover, the thermal diffusivity and thermal effusivity of epoxy and composite samples have been measured by using the photoacoustic technique, where a high enhancement of the thermal diffusivity with increasing ferrite content has been observed which can be attributed to the higher number of phonon vibrational modes as well as the longer mean free path of the ferrite nanoparticles due to their crystalline structure as compared to the amorphous structure of epoxy. Moreover, the formation of a percolated network of NiZn ferrite nanoparticles inside the epoxy may enhance the phonon conduction, increasing the value of the thermal diffusivity in the bulk of the samples. On the other hand, the almost constant values of the thermal effusivity-which is a surface property-suggest that these composites may be used not only for electromagnetic interference suppression but also for thermal shielding in electronic circuits. [ABSTRACT FROM AUTHOR]

A series of Gd-substituted Ba-Co-based (M-type) hexaferrites having the chemical compositions of BaCoGdFeO ( x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) were prepared by co-precipitation method. The pellets formed by co-precipitated powder were calcined at a temperature of 1200°C for 20 h. Final sintering was done at 1320°C for 4 h. From the x-ray diffraction analysis, it was revealed that all the samples showed M-type hexagonal structure as a major phase. The scanning electron microscope was used to examine the morphology of the sintered ferrites. The average grain size estimated by the line intercept method was found to be in the range of 2.8-1.0 μm. The room temperature DC resistivity increases with increasing Gd-contents to make these ferrites useful for high frequency applications and microwave devices. Lower values of coercivity ( H) and higher saturation magnetization ( M) may be suitable to enhance the permeability of these ferrites, which is favorable for impedance matching in microwave absorption. In addition, reflection coefficients for a sample was also measured from a frequency of 1 MHz to 3 GHz and a reflection peak was observed at about 2.2 GHz. [ABSTRACT FROM AUTHOR]

Nanocrystalline spinel ferrites of nominal stoichiometry NiZnMnFeO ( x = 0.0, 0.1, 0.2, 0.3, 0.4) were synthesized by chemical co-precipitation. X-ray diffraction analysis revealed formation of a single cubic phase with no metal oxide secondary phase; increased intensity of peaks of the doped samples suggests that, in the range studied, substituents are completely dissolved in the cubic lattice. Grain size was measured by scanning electron microscopy, by use of the line intercept method. Dielectric measurements were obtained as a function of frequency in the range 20 Hz to 3 MHz. It was found that hopping conduction was the predominant mechanism of conduction in frequency-dependent alternating current conductivity. Conductivity relaxation of the charge carriers was examined by use of the electrical modulus formalism; the results were indicative of the presence of the non-Debye-type relaxation in the ferrites. The grain boundary contribution was clearly apparent from Cole-Cole plots. Hysteresis loops for all the samples were narrow with low values of coercivity and retentivity, indicative of the superparamagnetic nature of these samples. On the basis of these sample characteristics it is suggested that Ni-Zn-Mn ferrites may be potential candidates for hyperthermia applications. [ABSTRACT FROM AUTHOR]

The new welding method known as F-MAG, which has been developed based on the CO2gas-shielded arc welding method (MAG), increases deposition rate of weld metal. The F-MAG welding method is combined with hot-wire, as has been used in TIG arc- and laser-welding methods. F-MAG is performed using hot-wire which is inserted into the rear part of the weld pool made with the leading electrode. Hot-wire melts by both electrical heating of itself and heat of the weld pool. Multi-layered weld metals were prepared using F-MAG and MAG. Microstructures and mechanical properties of both as-weld and reheated zones in the uppermost layer of the multi-layered weld metals formed with F-MAG and MAG were examined and the effects of hot-wire on microstructures and mechanical properties were analysed. Both the as-weld and reheated zones of the weld metal formed with F-MAG consisted of acicular ferrite (AF), equiaxed ferrite and so on. Both strength and elongation in as-weld and reheated zones formed with F-MAG were superior compared with those formed with MAG. It could be suggested that strength increased by refinement of AF due to increase in the concentration of alloying elements being contained in the hot-wire. Larger elongation of the weld metal in F-MAG compared with that in MAG could be analysed in terms of the Aggregate of AF Laths with nearly Parallel Slip systems between neighboring AF laths (ALPS). The number of AFs contained in an ALPS formed with FMAG is larger than that with MAG, in spite of the sizes of ALPSs formed with MAG and F-MAG being almost same. Deformation occurs over a lot of AFs in the case of finer AF formed with F-MAG through the rotation of the tensile test piece during deformation, resulting in the larger elongation. [ABSTRACT FROM AUTHOR]

The effects of ferrite phase characteristics and deformation in α + γ two-phase region on microstructure development and mechanical properties of low-silicon content TRIP-assisted steels was investigated. Laboratory simulation of controlled-thermomechanical processing (TMP) were carried out using an automated hot-compression testing machine and the TMP process parameters were changed in order to generate various microstructures with different ferrite phase characteristics (volume fraction, grain size, morphology). It was found that variation of ultimate tensile strength ( T S ) was predominantly governed by the changes in the fraction of hard phases of martensite and bainite whereas variation of total elongation ( T − E l % ), in general, coincided with the changes in retained austenite volume fraction ( V R A ) . The optimum combination of strength and ductility (29,800 MPa%) was obtained in the sample deformed to a true strain of −0.15 at 650 °C in intercritical region. [ABSTRACT FROM AUTHOR]

A series of M-type hexaferrites with chemical formula Ba 0.25 Sr 0.75 Pr x Fe 12− x O 19 ( x =0.00, 0.05, 0.10, 0.15, 0.20, 0.25) were synthesized using sol–gel autocombustion method. The samples were pre-sintered at a temperature of 800 °C for 3 h and were finally sintered at 1200 °C for 1 h at the heating rate of 10 °C/min. The thermal properties of the specimen have been investigated by thermogravimetric and differential thermal analyses. The structures and micrographs of the samples were systematically examined by X-ray diffraction and scanning electron microscopy, respectively. Vibrating sample magnetometer was also used in order to study the magnetic parameters of these ferrites. The hard magnetic behavior was confirmed by M–H loops for all the samples except for the sample with x =0.10 concentration which exhibits maximum saturation magnetization ( M s ) and a few hundred oersteds of coercivity ( H c ). Thus high M s and low H c cause to increase the permeability of the sample which is favorable for impedance matching in microwave absorption. [ABSTRACT FROM AUTHOR]

Results of broadband dielectric investigations of samarium doped bismuth ferrite ceramics are presented in wide temperature range (20-800 K). At temperatures higher than 400 K, the dielectric properties of samarium bismuth ferrite ceramics are governed by Maxwell-Wagner relaxation and electrical conductivity. The DC conductivity increases and activation energy decreases with samarium concentration. In samarium doped bismuth ferrite, the ferroelectric phase transition temperature decreases with samarium concentration and finally no ferroelectric order is observed at x = 0.2. At lower temperatures, the dielectric properties of ferroelectric samarium doped bismuth ferrite are governed by ferroelectric domains dynamics. Ceramics with x = 0.2 exhibit the relaxorlike behaviour. [ABSTRACT FROM AUTHOR]

The time-dependent study at mild hydrothermal conditions revealed the kinetic relation between structurally unrelated bismuth ferrites. We report the synthetic conditions that disclose the in situ transformation of Bi25FeO39 into BiFeO3 by only extending the time for crystallization. We also demonstrate how a careful investigation of the early stages of multiferroics crystallization provides cheap and easy room-temperature access to the important sillenite-type of structure of Bi25FeO39. The crystal structure analysis by the Rietveld method and magnetization measurements provided detailed structure and magnetic relations between the synthesis conditions and the properties of the run product. The BiFeO3 antiferromagnetic behavior with a small ferromagnetic component arising from the particle's surface uncompensated spins is ascertained. [ABSTRACT FROM AUTHOR]

Nanoparticles of Ni0.92Ca0.08Fe2O4 ferrite was prepared by the citrate precursor method. The effect of sintering temperature and sintering time on the structural, magnetic, and thermal properties of the prepared samples were investigated by using x-ray diffraction (XRD) and transmission electron microscope (TEM), vibrating sample magnetometer (VSM), and photoacoustic (PA) technique, respectively. The grain size of the sintered samples estimated from the XRD and the TEM results inform that the increase in the particle size is more announced by increasing the sintering temperature than increasing the sintering time. The unexpected decrease of the saturation magnetization of the sintered samples is ascribed to the dominant effect of the cation distribution which is affected by the sintering process. The cation distribution of the present samples was obtained from the analysis of the magnetization measurements and XRD data. The increase of measured density and the decrease of porosity of the sintered samples as a result of the grain growth have the obvious effect of increasing their thermal diffusivity. [ABSTRACT FROM AUTHOR]

This work aims to study the effect of gamma radiation on the structure, thermal and electrical properties of PS/ferrite composite. The Ni0.6Cd0.4Fe2-xSmxO4 was prepared using a conventional sintering ceramic process. Ferrite powder and Styrene was mixed and achieve polymerization process by gamma irradiation at 50 kGy. The composite samples have single spinel phase structure. Stability of the crystalline structure and no phase transition due to irradiation are found. The bulk density decreases whereas X-ray density increases with increasing Sm contents for both ferrite and PS/ferrite. The tetrahedral radii rA remains constant with Sm content but octahedral radii rB increases for both ferrite and PS/ferrite composite. The grain size shows increasing trend for PS/ferrite composite. The PS nearly coat the grains and so their boundaries become faint and not sharp. The gamma radiation transfer Fe3+ to Fe2+ due to its ionizing effect. The Fe2+ occupy octahedral site and the stretching vibration of its bond with oxygen (Fe2+-O2-) gives absorption at about 392 cm-1, near octahedral absorption at 462 cm-1. The PS/Ni0.6Cd0.4SmxFe2-xO4 composite becomes thermally more stable than pure polystyrene. The activation energy of conduction Eσ has a small values and in the range of hopping conduction mechanism. [ABSTRACT FROM AUTHOR]

Monodisperse spherical nanoparticles of MFe O (M = Mn, Co, Ni) with controlled diameter (5-20 nm) were synthesized by solvothermal decomposition of [MFe O(CHCO)(HO)] complexes in poly- and tetraethylene glycol. The samples were studied by XRD, TEM, and SQUID magnetometry. The nanoparticles have superparamagnetic behavior. The blocking temperature, magnetization, and magnetic anisotropy barrier decrease, while the magnetic anisotropy constant increases with decreasing particle size. [ABSTRACT FROM AUTHOR]

Li-Zn-Ti ferrite doped with 0.5 wt.% to 16 wt.% HBO-BiO-SiO-ZnO (BBSZ) glass was synthesized using a low-temperature ceramic sintering process. Selected parameters of saturation induction ( B), coercivity ( H), Curie temperature ( T), and complex permeability spectra were measured as functions of doping content, and their relationships with ferrite density and microstructure are discussed. It was found that Li-Zn-Ti ferrite can be fired at low temperature (900°C) with BBSZ glass content varying from 0.5 wt.% to 2 wt.%. The real permeability increased from 80 to 190 in the frequency range from 1 MHz to 3 MHz, the saturation induction B increased from 105 mT to 150 mT at 1 kHz, whereas the coercivity H decreased from 165 A/m to 65 A/m at 1 kHz and the Curie temperature T slightly declined from 155°C to 143°C. These results confirm that this new ferrite material could be used in low-temperature cofired ceramic (LTCC) devices. [ABSTRACT FROM AUTHOR]

Highlights: [•] The saturation magnetization increases with heat-treatment temperature until 1200°C. [•] 1200°C sample presents, at 5K, a magnetic moment of 73emu/g and 66emu/g at 300K. [•] Heat-treatment promotes the formation of lithium ferrate and hematite, decreasing the magnetic moment. [ABSTRACT FROM AUTHOR]

This paper presents a new approach for incorporating the thermal effect on the magnetic hysteresis of the 3F3 material. The proposed algorithm is based on the knowledge of the magnetic flux density spectrum for some temperatures. So, a feed-forward neural network is trained to learn the relation between the rank of harmonics, the temperature and the amplitude of each harmonic. To construct the hysteresis loop for a new value of the temperature, the neural network predicts the spectrum of the magnetic flux density B which is transformed back to the time domain. [ABSTRACT FROM AUTHOR]

The effects of microwave calcination (MC) and conventional muffle furnace calcination (CC) on the microstructure and magnetic properties of M-type hexagonal ferrite Ca0.15La0.39Sr0.46Fe11.7Co0.3O19 were investigated. The phase composition, microstructure, and magnetic properties of calcined materials were examined using X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibrating sample magnetometry. Experiments indicated that the MC method can achieve both pure phase, and fine and uniform grains for both calcined and sintered M-type hexaferrites. MC treatments resulted in a magnetization at 15 kOe of 67 emu/g and an increase in coercivity by 12% over the CC technique. The improved magnetic properties resulting from microwave-assisted calcination were attributed to the formation of a fine-grained morphology, which yielded a narrow grain size distribution. The microwave calcinating technique was shown here to possess unique potential for fabrication of high-performance ferrites and possibly other ceramics. [ABSTRACT FROM AUTHOR]

Abstract: In this research, NiZn ferrite nanoparticles were incorporated in thermoplastic natural rubber matrix (TPNR) as reinforcing magnetic nanofiller by melt blending technique. TPNR was prepared from high-density polyethylene (HDPE), natural rubber (NR) and liquid natural rubber (LNR) in a ratio of 70:20:10 and later impregnated with 4, 8, 12 (wt%) of NiZn ferrite nanoparticles. Thermal stability, temperature dependence of coercivity and microwave absorption characteristics of the nanocomposite samples were investigated using thermogravimetric analyser (TGA), vibrating sample magnetometer (VSM) and vector network analyser (VNA), respectively. The results showed that the thermal stability of the nanocomposite samples has increased with increasing filler content in the TPNR matrix. Temperature dependence of coercivity for pure NiZn ferrite and nanocomposite samples exhibited immeasurable values below blocking temperature (T B), above which an abrupt increase was observed. In addition, the microwave absorption results showed multi-absorbing peaks characteristic with a great enhancement attained for 12wt% nanocomposite at a sample thickness of 7mm with a potential application in the X-band frequency. [Copyright &y& Elsevier]

Aluminium-nitride precipitation is of great importance in the deep drawability of Al killed low carbon steels. The industrial processing of Al killed steel has some critical points at which the drawability of the final product is strongly influenced by the processing parameters (hot rolling end temperature, coiling temperature). The nitrides are dissolved at the slab reheating temperature (1250°C), and most of the nitrogen remains in solid solution until the hot rolling finishes. The precipitation of nitrides in ferrite occurs more quickly than in austenite, consequently the coiling temperature must be enough low to keep the nitrogen in solid solution. The main purpose of this paper is to describe the aluminium-nitride precipitation process in hot rolled coil. Moreover, on the basis of a phenomenological model of the precipitation process the precipitated fraction of nitrides coiling has been calculated. [ABSTRACT FROM AUTHOR]