Preparation and Characterization of Barium and Strontium Hexaferrite Employing Recycled Millscale

In this project work, permanent magnet barium/ strontium hexaferrite materials was prepared from millscale, using hematite derived from millscale by the Curie Temperature Separation Technique (CTST). The excellent CTST isolation and purification of wustite,FeO contained in the millscale and converted to hematite,Fe2O3, was confirmed by X-Ray Diffraction (XRD) pattern analysis and element analysis by Electron Dispersive X-Ray (EDAX). The sample was prepared by recycling the waste product from Malaysian steel-making factories. Using a Curie temperature separation technique, the wustite,FeO contained in the millscale was separated by this new technique using deionized water at 90oC/100oC in the presence of 1T external magnetic field. The wustite iv was then oxidized in air at 400oC/500oC/600oC for 10 hours. An XRD phase analysis showed that a very high percentage of Fe2O3 was present in the final powder preparation. A conventional ceramic powder processing method was then carried out to prepare hexagonal BaFe12O19 and SrFe12O19 pallet shaped samples. Analysis of samples was done on density, resistivity, X-Ray Diffraction (XRD), Particle Size Analysis (PSD), Electron Dispersive X-Ray (EDAX), Scanning Electron Micrsocopy (SEM), grain size, saturation magnetization, coercive force and remanence. The effect of prolonged milling time shows a positive tendency for the formation of needle shape microstructure (0.3μm-1μm) of barium hexaferrite. The magnetic properties were measured using an Approximation Method (APM) theory. The 3.33 kG high remanence , 0.74 kG saturation magnetisation and 2.857 kOe coercive force of the sample derived from millscale shows that recycling a waste steel-making product has a high potential to produce a low cost ferrite in the future

Da’wah and creativity: adopting transdisciplinary expertise in transmitting the messages of Islam to others

Living in a sophisticated world today always require people to adjust themselves accordingly. The same goes to the work of da’wah (the act of propagation of Islam) by the Muslims. This study discusses efforts made by a group of undergraduate students from different specializations attending Islamic Da’wah course (RKUD 2030) at the International Islamic University Malaysia to deliver the messages of Islam to the targeted recipients by using the most effective methods. The students are divided into several groups and required to find current psychosocial issues reported in the media. These issues are turned into problems in which they must think of a solution by using the most effective and creative method. As a result, various creative methods were invented to transmit the messages to the intended recipients. The students are able to adopt their transdisciplinary knowledge and skills in producing the best da’wah methodology

Electrical conductivity and dielectric behaviour of manganese and vanadium mixed oxide prepared by conventional solid state method

Investigation on electrical conductivity and dielectric properties of manganese (Mn) and vanadium (V) mixed oxides were carried out to study the extrinsic semiconductor behaviour. The XRD pattern shows that Mn–V oxide is multiphase and quantitative phase analysis was performed to determine the relative phases. Overall results indicate that with increasing temperature, the DC conductivity, AC conductivity, dielectric constant, dielectric loss factor and loss tangent of Mn–V mixed oxide increases. Activation energy of AC conduction decreases with increase in frequency, confirms that the hopping conduction is the dominant mechanism. The activation energy of DC conduction ΔEdc is 0.54 eV which is greater than ΔEdc. There are three types of dielectric constant spectrum found in the measuring temperature range 30–250 °C. This is possibly due to the extrinsic behaviour of the Mn–V oxide. Dielectric relaxation characteristic was obtained from the spectrum of the imaginary part of electric modulus. The activation energy of the relaxation process and the relaxation time at infinite temperature are 0.42 eV and 5.40 ps respectively. The Nyquist plot of complex impedance fitted the equivalent circuit model of two RC circuits in series with R and C in parallel. The relaxation time was estimated from the circuit model

Study the iron environments of the steel waste product and its possible potential applications in ferrites

In this project, the permanent magnets ferrites have been prepared by recycle the steel waste product. Steel waste is an impure material that contains the iron oxides and impurities. The steel waste product is a form of flakes is grinding for several hours to form a fine powder. The iron oxides powders are separated from magnetic and non-magnetic particle using magnetic particle separation. The magnetic particles was again been purified by using the Curie temperature separation. The magnetic powder carried out from the purification was heated at 500 o C for 6 hours at 6 o C/ mins to form hematite, Fe 2 O 3. The constitute amount of BaCO 3 and Fe 2 O 3 derived by steel waste product are mixed by using mechanical alloying to prepare the barium hexaferrites (BaFe 12 O 19). The samples were sintered at different temperature 600/800/1000/1200 o C for 6 hours at 6 o C/ mins. The composition of FeO, Fe 3 O 4 and Fe 2 O 3 of the steel waste product was carried out using X-ray Fluorescence (XRF) and Energy Dispersive Spectroscopy (EDAX). The crystallography of sample is observed by using X-ray Diffraction (XRD). Microstructure of samples was carried out by using Field Emission Scanning Electron Microscope (FESEM) and Atomic Force Microscopy (AFM). The saturation magnetization, Curie temperature and density are also observed. The results show the purification process yields high purity of hematite, Fe 2 O 3. The common characteristics of the steel waste product are its low cost, availability and thus the potential for large production volumes, need for recycling, and tendency to further oxidation in the production of ferrites

Effect of pH variation on magnetic properties of strontium hexaferrite nanoparticles synthesized by sol gel process

A strontium ferrite (SrFe12O19) nanoparticle was prepared by sol gel auto combustion method at 800°C and 900°C and at various pH (pH 1, 3 and 5). The SrFe12O19 powder was characterized by using Thermogravimetric analyses (TGA), X-Ray Diffraction (XRD), Vibrating Sample Magnetometer (VSM), and Field emission Scanning Microscope (FeSEM) to investigate thermal behavior, crystalline structure, magnetic properties and morphology. To review, the single crystal size of SrFe12O19 was found at 900°C has lower weight loss about 30.44%, crystalline size of 70.5 nm with Mr, Ms, and Hc were 64036 G, 44.188 emu/g and 27.593 emu/g. The average grain size was 80 ~ 100 nm. In brief, as pH increase, the Mr, Ms and Hc were increases

Structural, phase development and magnetic behavior of polycrystalline yttrium iron garnet

The interest of this work is to investigate the influence of sintering temperatures on the structural, phase development and the magnetic properties of polycrystalline yttrium iron garnet (Y3Fe5O12, YIG). The samples were prepared using α-Fe2O3 and Y2O3 as starting powders by employing a high-energy ball milling (HEBM) technique using a SPEX8000D mill and milled for 9 h. The samples were sintered for 9 h from 500 °C to 1400 °C with increments of 100 °C. Particle size analysis was carried out using a Transmission electron microscope (TEM). The phase development and crystallography study were determined using X-ray Diffractometer (XRD). Field emission scanning electron microscope (FeSEM) was used to study the morphology and microstructural evolutions of YIG. Parallel evolution on magnetic permeability components and Curie temperature were characterized by impedance analyzer. Magnetization-hysteresis (M-H) curve parameters were obtained from a vibrating sample magnetometer (VSM). The change in particle size from nano to micro was also studied with respect to sintering temperatures, structural, phase development and magnetic properties

Enhancing absorption properties of Mg–Ti substituted barium hexaferrite nanocomposite through the addition of MWCNT

M-type barium ferrite with Mg–Ti substitution and MWCNT addition was synthesized using high-energy ball milling. The prepared sample was further analyzed using X-ray diffraction, field emission scanning electron microscope (FESEM), vibrating sample magnetometer and vector network analyzer. The results showed that the particle size had a wide range of distribution, and a hexagonal structure was formed in the sample. The sample was observed to have lower saturation magnetization and coercivity after Mg–Ti was substituted with MWCNT and added into the barium hexaferrite. Reflection loss was studied as a function of frequency and thickness of the sample. For Mg–Ti substituted barium hexaferrite composite with a thickness of 2.0 mm, the reflection loss peaked at −28.83 dB at a frequency of 15.57 GHz with a bandwidth of 6.43 GHz at a loss of less than −10 dB. The microwave absorption primarily resulted from magnetic losses caused by magnetization relaxation, domain wall resonance, and natural resonance. FESEM micrograph demonstrated that carbon nanotubes were attached to the external surface of the ferrite nanoparticles. The investigation of the microwave absorption indicated that with an addition of carbon nanotubes, the real and imaginary parts of permittivity and reflection loss had enhanced to −34.16 dB at a frequency of 14.19 GHz with a bandwidth of 5.72 GHz

Microstructure and nonlinear properties of Zn-V-Mn-Nb-O varistor ceramics with Nd2O3 substitution

An abnormal grain growth of the ZnO-based ceramics due to highly reactive vanadium liquid phase disrupts its nonlinear properties. The effect of Nd2O3 concentration from 0.01 to 0.05 mol% on microstructure and electrical properties of ZnO-based varistor ceramics were investigated. The sample was fabricated via solid state method and sintered at 900 °C for 2 h. XRD analysis shows the V2O5 and Zn2Nb2Mn2O9 phase formation. SEM analysis shows the grain is more uniform and enlarged to 3.54 μm with Nd2O3 addition up to 0.03 mol%. Nd2O3 also increased both the nonlinear coefficient α and the breakdown electric field, E1mA to an optimum of 9.94 and 75 V/mm. Beyond that concentration, oxygen O vacancy formed at the grain boundary and diminished the electrical properties

The effect of sintering time on the microstructural and nonlinear electrical properties of Zn-V-Mn-Nb-Gd-O low-voltage varistor ceramics

There is lacking of study on the prolonged sintering time effect on the microstructural and nonlinear electrical properties of ZnO-V2O5-MnO2-Nb2O5-Gd2O3-based low-voltage varistor ceramics sintered at 900 °C. The aim of this study is to investigate the effect of sintering time from 120 to 210 mins on the microstructural and nonlinear electrical properties of the ceramics. The prolonged sintering time normally is expected to disrupt the microstructural and to decrease the nonlinear electrical properties of the ceramics. The sample was prepared via solid-state method and sintered at 900 °C. XRD results shows that the MnV, GdMnO3, Mn2Nb2Zn2O9 and ZnV2O4 phase disappeared with increasing sintering time. The ZnO peak shift to the low diffraction angle from 47.5341 to 47.4995° and the interplanar space increases slightly from 1.9129 to 1.9142 Å. The density decreases from 5.22 to 4.62 gcm−3. The average grain size decreases from 3.56 to 3.19 μm due to pinning action by Gd2O3 at the grain boundary which accelerate the annihilation of Zn and O elements as shown by EDX maps. Thus, the barrier height decreases from 0.67 to 0.65eV and nonlinear value is decreases as expected from 9.91 to 7.01 and correspondingly the breakdown field E1mA decreases from 88.48 to 71.04 V/mm at 210 min

Structural and magnetic properties of yttrium iron garnet (YIG) and yttrium aluminum iron garnet (YAlG) nanoferrite via sol-gel synthesis

The structural and magnetic properties of yttrium iron garnet (YIG) and yttrium aluminum iron garnet (Y3AlxFe5−xO12, YAIG) (x = 0.2, 0.6, 1, 1.4, 1.8, and 2.2) nanoparticles were investigated. The samples were prepared via auto combustion sol-gel technique, using citric acid as chelating agent and fuel for the combustion process. The obtained powder was heated at 950 °C. X-ray diffraction peaks confirmed the garnet phase formation. Crystallite size increases with Al from 28.5894 to 28.6170 nm. Lattice constant of the samples was found to decrease from 12.4674 Å to 12.3233 Å as Al increase from 0.0 to 2.2. FTIR was used to confirm the garnet structure, the main vibrating modes were observed to shift to higher wave number with increasing Al concentration. Saturation magnetization, Ms shows a decreasing trend from 20.721 to 0.7586 emu/g with increasing Al from 0.0 to 2.2. Furthermore, the decreasing trends in the static magnetic properties of YAIG samples may be due to the introduction of Al ions in the YIG crystal lattice. High content of Al substitution on YIG leads to paramagnetic behavior of the ferrite. The grain size decreased from 0.64 μm to 0.32 μm, while the bulk density decreased from 5.058 gcm−3 to 4.233 gcm−3 as Al increase from 0.0 to 2.2