Preparation and characterization of Sr1−xNdxFe12O19 derived from steel-waste product via mechanical alloying

Steel waste product had been used as the main source of raw material in the preparation of permanent magnets ferrites. Steel waste product is an impure material that contains the iron oxide and impurities. The steel waste product is a form of flakes is grinding for several hours to form a fine powder. The iron oxide powder is separated from magnetic and non-magnetic particle using magnetic particle separation. The magnetic particle was again been purified by using the Curie temperature separation technique. The magnetic powder was carried out from the purification and oxidize at 500 °C for 6 hours at 2 °C/ mins to form the hematite, Fe2O3, used as a raw powder to prepare SrFe12O19. Microstructure of Nd-doped strontium ferrites, Sr1-xNdxFe12O19, with x = 0.0, 0.1, 0.2, 0.3, 0.4 and 0.5, were prepared through a mechanical alloying technique. Several characterizations have been done, such as X-ray Diffraction (XRD) and Field emission scanning electron microscopy (FESEM). The magnetic properties of coercivity (Hc) and the energy product BHmax of samples are carried out. The magnetic properties of samples were investigated with an expectation of enhancing the magnetic properties by substitutions of Nd3+ ions on Fe3+ ion basis sites. The saturation magnetization Ms revealed magnetic behavior with respect to Nd3+ doping concentration, showing a decrease. The coercivity Hc increased with increasing Nd3+ doping concentration

Magnetic properties and microstructures of cobalt substituted barium hexaferrites derived from steel waste product via mechanical alloying technique

The mechanical alloying technique was used to prepare barium hexaferrite (BaM) with 3, 5, 10 and 20 wt% cobalt oxide (Co3O4). In this work, steel waste flakes were cold-rolling steel mill for several hours to form a fine powder. The steel waste powder was purified by using magnetic separation to isolate the magnetic and non magnetic particles. The method was continued for Curie temperature separation technique to separate the magnetic ions by varied Curie temperature of the magnetic powder. The purified powder was then oxidize at 500 °C at 6 °C/mins to form hematite, Fe2O3. The steel waste-derived hematite was used as the raw material in preparing BaM ferrites. The BaCO3, Fe2O3and different percentages of Co3O4 (Co) were mixed and milled for several hours by using mechanical alloying. The powder were pelletised in 11 × 1 mm (diameter × height) and the sintered at 1200 °C for 10 hours. The addition of Co2+/3+ ions to the BaM shows a varying in the magnetic properties of BaM. By increasing the Co doping, the remanence Mr was reduced from 17.6 emu/g to 6.2 emu/g. The coercivity Hc results varying magnitude from 102 Oe to 1079 Oe. The Mr and Hc of undoped BaM is obtain at 14.6 emu/g and 860 Oe, respectively. The grain size of BaM also increases with Co doping. The densities of the compounds are decreasing with increasing Co doping with a maximum value of 4.2 g/cm3

Effect of variation sintering temperature on magnetic permeability and grain sizes of Y3Fe5O12 via mechanical alloying technique

This work will focus on the preparation of yttrium iron garnet (Y3Fe5O12, YIG) via mechanical alloying technique derive by steel waste product. The Fe2O3 powder derived from the steel waste purified by using magnetic and non-magnetic particles (MNM) and Curie temperature separation (CTS) technique. The purified powder was then oxidized in air at 500 °C for 9 hours in air. The Fe2O3 was mixed with Y2O3 using high energy ball milling for 9 hours. The mixed powder obtained was pressed and sintered at different temperature 500/600/700/800/900/1000/1100 °C. X-ray diffraction (XRD) shows the YIG is completely form at 1100 °C. The field emission scanning electron microscopy (FESEM) images shows the grain size increases as increase the sintering temperatures. The frequency dependence on the complex permeability, µ’ and magnetic loss, µ’’ in the frequency range 10 MHz to 1 GHz were measured in this study. The results showed that the highest μ΄ is 5.890 obtained from 1100 °C

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

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

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

Preparation and characterization of SrM₀.₅Fe₁₁.₅O₁₉ derived from mill scale with substitution M= Co, Cu, Ni, Zn, Ti, Nd via mechanical alloying

It is interesting to see the changes on structural and magnetic properties of strontium hexaferrites on the addition of metal element such as Co, Cu, Ni, Zn, Ti, and Nd for future device applications. Here the aims of the projects are to produce the undoped and doped strontium ferrite (Co, Cu, Ni, Zn, Ti, and Nd) from mill scales as raw iron compound by using a high-energy ball milling (HEBM) technique. Secondly to study the effect of Co, Cu, Ni, Zn, Ti, and Nd substitution in strontium hexaferrite and compare with undoped strontium hexaferrite on its structural, microstructure, magnetic, thermal and density properties. In order to achieve the first objective, the undoped and doped strontium hexaferrites, mill scales as the main sources of iron oxide Fe2O3 undergo two stages of purification process that are magnetic separation technique and curie temperature separation technique. The powders of 0.5 molar ratio of various metal oxides (Co, Cu, Ni, Zn, Ti, and Nd), strontium carbonate (SrCO3), and iron oxides (Fe2O3) were milling by employing HEBM following the formula SrM0.5Fe11.5O19. The resulting powder were then moulded into rod and pellets with diameters and height 10 mm × 10 mm and 10 mm × 2 mm respectively and sintered at 1300 ⁰C. For the second objective, the doped and undoped was characterized by XRD, FESEM, EDX, FTIR, VSM, BH-tracer, Photoflash Technique to measure thermal diffusivity (k) Precision Impedence Analyser to measure Curie temperature (Tc), and densimeter. The XRD patterns confirmed the formation of the single phase hexagonal ferrite structure for all samples, with space group P63/mmc. The XRD analysis exhibits an excess compound of Fe2O3 for Ti, Nd and Ni cations substitution. The analysis also shows increase in calculated lattice parameters a, c and cell volumes (Vcell) indicating the solubility of substituted cation in hexagonal structure of strontium ferrite. The average crystallite size from XRD for different substitution is in the range of 40 to 70 nm. From FESEM images, the samples with homogenous surface and hexagonal geometry have an average particle size in the range of 1 to 4 μm. The corresponding peaks of Co, Cu, Ni, Zn, Ti, and Nd were observed from EDX confirms the metal substitution. The FTIR spectra showed characteristic peaks for strontium hexaferrite was detected between 650 cm1 to 450 cm1 for all samples. The Tc values for undoped, Co, Cu, Ni, Zn, Ti, and Nd were 390, 330, 292, 290, 287, 270 and 266 °C respectively. From B-H tracer the value of Ms for undoped is 2546 Gs was in the range of common magnetic properties for ferrite 2000 to 3000 Gs (Cullity and Graham, 2009) while Ms for Zn = 3284 Gs and Ni = 3154 Gs doped was higher than that of common ferrite. The Hc of strontium hexaferrite decreases largely from a value of 1160 Oe for the pure samples to 332, 02, 281, 260, 127 and 64 Oe for Cu, Co, Zn, Ti, Nd and Ni metal cations, respectively. The substitutions have decreased the value of Hc and Mr compared with undoped strontium hexaferrite. The value of Mr for undoped strontium hexaferrite is 1576 Gs while the remanence for Zn, Cu, Co, Ni, Ti and Nd was 955, 873, 839, 727, 714 and 165 Gs, respectively

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