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

Elemental analysis and IR band characteristics of α-Fe2O3 and BaFe12O19 steel waste product based

This project focused on the elemental analysis and IR band characteristic of -Fe2O3 derived from recycled steel waste product. The steel waste flakes were ball milling for several hours to form a fine powder. The steel waste powder had been purified by using impurity separation technique and magnetic separation technique. The purified steel waste powder then oxidized at 500 oC to form hematite (Fe2O3). The hematite were used to synthesize BaFe12O19 by using salt-melt method. The samples were characterized using X-ray Fluorescence (XRF), Fourier Transform Infrared spectroscopy (FTIR), X-ray diffraction (XRD) and energy-dispersive X-ray analysis (EDAX). The XRF and FTIR results show the formation of Fe2O3, the IR characteristic bands of Fe2O3 and single phase BaFe12O19 is obtained from recycled steel waste product

Annealing study of α-Fe2O3 nanoparticles steel-waste based: microstructure and magnetic behavior

The interest of this paper is to show the influence of annealing process on magnetic properties and microstructure of -Fe2O3 derived from steel waste product (mill scales). The mill scales flakes were wet ball milling for several hours to form a fine powder. The mill scales powder was purified by using magnetic separation to isolate the magnetic and non magnetic particles. The method was continue for Curie temperature separation technique. The purified powder was annealed at 400/450/500 and 550 °C at 6 oC/mins to form hematite, -Fe2O3. The annealed powders were milled for several hours by using mechanical alloying. Annealing at varied temperatures produced α-Fe2O3 nanopowders with average crystallite size 18.1 nm to 28.6 nm. Phase transformation occurred directly by annealing in air, conversion of FeO and Fe3O4 phase to form α-Fe2O3. The correlation between the magnetic properties and microstructure, of the sintered powders at 1200 oC enables to obtain microphase of α-Fe2O3 and Fe3O4 with different particle size and magnetic properties. The resultant α-Fe2O3 nanopowders are ferromagnetic with moderate coercivities

Synthesis and characterization of barium hexaferrites derived from steel waste by ammonium nitrate salt melt synthesis

In this paper, a series of barium hexaferrite BaFe12O19 with different powder to salt ratio (1:3, 1:4, 1:5) were prepared using ammonium salt melt technique. Iron oxide were process from steel waste product were mixed with barium carbonate, used as starting materials to produce barium hexaferrites. The ammonium nitrates in this experiment act as oxidizing agent in this synthesis. The BaFe12O19 powders were sintered at 1300°C for six hours and characterized using X-ray diffraction (XRD), Fourier transform Infrared (FTIR), Vibrating Sample Magnetometer (VSM) and Field emission Scanning Microscope (FeSEM) to investigate its crystallography, magnetic properties and morphology. The maximum coercivity and saturation magnetization obtained for sample ratio 1:3 of 1017 G and 90.9 emu/g, respectively. Increase the salt ratio decrease the coercivity and saturation magnetization values

Structural and magnetic properties of aluminum substituted yttrium iron garnet via sol-gel synthesis

Aluminum-substituted yttrium iron garnet (Al-YIG) powders was synthesize by using sol-gel citrate nitrate combustion technique with different doping concentration (x = 0.4, 0.6 and 1.0). The Y3-x Alx Fe5O12 samples were analyse of phase, structural and hysteresis by using X-ray diffraction (XRD), Fourier transform infra-red (FTIR) and Vibrating Sample Magnetometer (VSM).The powder resulted a single phase nanostructured garnet was formed. Room temperature saturation magnetization Ms and coercivity of Al-YIG powders decreased as a function of increasing Al content. The samples has a room temperature Ms of 9.2 emu/g and decreased to 1.5 emu/g. Coercivity Hc value decreases from 71.7 G to 51.4 G

Composition and magnetic properties of aluminium substituted yttrium iron garnet waste mill scales derived via mechanical alloying technique

This paper presents the effects of aluminium substitution on sample composition, density and magnetic properties of yttrium iron garnet, Y3Fe5O12 (YIG). Mill scales, in a form of flakes was obtained from the steel industry in Malaysia. The mill scales was purified to produce high purity hematite, Fe2O3. The mill scales derived Fe2O3 were used as raw material to prepare the aluminum substituted yttrium iron garnet Y3Fe(5-x) Al(x) O12 (Al-YIG) with variation compositional x = 0.0, 0.5, 1.0, 1.5 and 2.0 using mechanical alloying technique. X-ray fluorescence (XRF) was used to investigate the percentage compositions of the raw mill scales. The magnetic hysteresis of sample were investigate by using B-H tracer (MATS). Density of the Al-YIG bulk samples was found to decrease with increasing xAl2O3 content. The saturation magnetization Ms also shows a decrease with increase xAl2O3 content. The maximum saturation magnetization Ms and coercivity Hc was found at 310 G and 14.98 Oe, respectively. With increase xAl2O3 to 2.0%, the Ms and Hc were reduced to 29.35 G and 3.15 Oe, respectively

Structural and magnetic properties of SRM0.5FE11.5O19 (M: TI4+, CO2+, NI2+, CU2+, and ZN2+) derived from steel waste product via mechanical alloying

This paper presents the steel waste product used as the main source of raw material in the preparation of permanent magnets ferrites, substitution with transition metal cation. M-type hexaferrites of SrM0.5Fe11.5O19 (M: Ti, Co, Ni, Cu, and Zn) component were investigated. Samples were prepared by Mechanical Alloying (MA) process and analysis microstructure of samples were characterized by using X-ray Diffraction (XRD). The specific saturation magnetization Ms, the coercivity Hc and remanence Mr was carried out using B–H hysteresis measurement. The XRD patterns show single phase of the magnetoplumbite strontium ferrite and Fe2O3 phases were only present in Ti4+ substitution. Significant increase in calculated lattice parameter a, c and cell volume Vcell from XRD indicating solubility of substituted cation in hexagonal structure of strontium ferrite. Magnetization measurements discovered that saturation magnetization Ms of the all samples proportional to magnetic moment μB of substituted cation with highest 28.33 emu/g from Co2+.While highest coercivity 26.5 kA/m from Co2+ and for remanence Zn2+ 0.955 Tesla. The magnetic properties such as remanence Br and coercivity Hc make the synthesized materials useful for high density recording media and permanent magnets

Synthesis and characterization of barium hexaferrites derived from steel waste using salt-melt technique

This project focused on the synthesis of barium hexaferrites derived from steel waste (also known as mill scales). The steel flakes were ball milling for several hours to form fine powders. The fine powders are purified using magnetic separation technique (MST) and Curie temperature separation technique (CTST). The purified steel waste powder then oxidized at 500 ºC to form hematite, Fe2O3. Fe2O3 powder was characterized using X-ray Fluorescence (XRF), Fourier Transform Infrared spectroscopy (FTIR), X-ray diffraction (XRD) and energy-dispersive X-ray analysis (EDX). The XRD and XRF results indicate the purified powder obtained are iron oxide Fe2O3 (ICDD 98006-9763) and show that the obtained powders have high content of Fe2O3 for about 99.051%. The Fe2O3 were used to synthesize BaFe12O19 by using salt-melt method. The samples were synthesized using different powder to salt weight ratio of BaCO3 + Fe2O3 and ammonium nitrate salt (NH4NO3). The NH4NO3 was melted at 170 ºC. The mixture of BaCO3 and Fe2O3 were added into the NH4NO3 melt solution and kept stirring for several hours using magnetic stirrer under control temperature of 170 oC. The heating temperature was then increased up to 260 oC for 24 hours to produce ash powders. The XRD show the peak of BaFe12O19 for all the samples and the presence of small amount of impurity Fe2O3 for sample’s ratio 1:5 and 1:6. Based on FTIR spectra, the bands appears at 542.71 cm-1 and 432.48 cm-1 corresponding to metal-oxygen bending and vibration of octahedral sites of BaFe12O19. The FESEM images shows that the grains of the samples appear to stick to each other and agglomerate at different masses throughout the image with the grain size 5.26, 5.88, 6.14, 6.22 and 6.18 μm for ratio 1:3, 1:4, 1:5, 1:6 and 1:7 respectively. From the VSM analysis, the magnetic properties of sample with a ratio 1:3 shows the highest value of coercivity Hc of 1317 Oe, saturation magnetization Ms of 91 emu/g and remnant Mr of 44 emu/g. The dielectric measurement shows that the BaFe12O19 samples have high dielectric loss and low ac conductivity. The complex permeability measured from VNA shows that the real part of permeability in the range of 1.0 to 1.2. The imaginary parts of permeability is in the range of 0 to 0.1. The minimum reflection loss is approximately around -3.9 dB to -4.33 dB for all samples.The first matching frequency in average of 8.8 GHz are due domain wall resonance for all samples while natural resonance appears at second matching frequency in average of 11.0 GHz. This project is significance have potential for used in the low cost, recycle approached permanent magnet fabrication that potentially used in motor, loudspeakers and electromagnetic (EM) absorber applications

Effect of sintering temperature on crystallography and microstructure of yttrium iron garnet via mechanical alloying technique

This work focused on the preparation of yttrium iron garnet (Y3Fe5O12, YIG) via mechanical alloying technique derived by steel waste product. The steel waste was purified by using magnetic and non-magnetic particles (MNM) and Curie temperature separation (CTS) technique. The powder from the CTS technique was oxidized at 500°C for 9 hours in air to form the iron oxide (Fe2O3). The Fe2O3 was mixed with Y2O3 using high energy ball milling for 9 hours. The obtained mixed powder was pressed and sintered at varied temperature 500/600/700/800/900/1000/1100/1200 °C. X-ray diffraction (XRD) showed the YIG was completely formed at 1100°C. The crystallite size and grain size of YIG powder were observed. The results show the grain size and crystallite size increased as a function of sintering temperatures

Influence of pH Adjustment Parameter for Sol–Gel Modification on Structural, Microstructure, and Magnetic Properties of Nanocrystalline Strontium Ferrite

Synthesis of nanocrystalline strontium ferrite (SrFe12O19) via sol–gel is sensitive to its modification parameters. Therefore, in this study, an attempt of regulating the pH as a sol–gel modification parameter during preparation of SrFe12O19 nanoparticles sintered at a low sintering temperature of 900 °C has been presented. The relationship of varying pH (pH 0 to 8) on structural, microstructures, and magnetic behaviors of SrFe12O19 nanoparticles were characterized by X-ray diffraction (XRD), field emission scanning microscope (FESEM), and vibrating sample magnetometer (VSM). Varying the pH of precursor exhibited a strong effect on the sintered density, crystal structure and magnetic properties of the SrFe12O19 nanoparticles. As the pH is 0, the SrFe12O19 produced relatively largest density, saturation magnetization, Ms , and coercivity, Hc, at a low sintering temperature of 900 °C. The grain size of SrFe12O19 is obtained in the range of 73.6 to 133.3 nm. The porosity of the sample affected the density and the magnetic properties of the SrFe12O19 ferrite. It is suggested that the low-temperature sintered SrFe12O19 at pH 0 displayed Ms of 44.19 emu/g and Hc of 6403.6 Oe, possessing a significant potential for applying in low-temperature co-fired ceramic permanent magnet