Structural and magnetic properties of FeCoC system obtained by mechanical alloying (original) (raw)
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Structural and Magnetic Properties of Mechanically Alloyed Fe50Co50 Systems
Acta Physica Polonica A, 2020
The nanostructured Fe-Co alloys were prepared by mechanical alloying of elemental powders using a highenergy ball mill. This made it possible to study the structural evolution of the milling product with the grinding time. In addition to previous X-ray diffraction and thermomagnetic investigations, 57 Fe based Mössbauer transmission spectroscopy was used for this purpose. Iron was alloyed with cobalt just after one hour of milling and bcc Fe-Co solid solution was formed. The analysis of the hyperfine magnetic field distribution proved that no significant structural changes occurred during further milling. A slight but regular increase in the standard deviation was observed, indicating an enhancement of topological disorder or/and an increase in internal stresses.
Journal of Alloys and Compounds, 2010
The mechanical alloying process has been used to prepare nanocrystalline Fe70−xCuxCo30 (x = 0, 3, 6, and 10) alloy from powder mixture. The structure and magnetic properties were investigated through powder X-ray diffraction (XRD), electron microscopy and magnetization measurements. The XRD patterns show a bcc crystal structure with lattice constant 0.2865 nm and crystallite size (D) of 15 nm evolves on 60 h milling in the case of Fe–Co alloy. But it is found that Cu speeds up the formation of bcc phase with finer microstructure (D = 7 nm for x = 10). Increase in microstrain is observed with the milling time and also with Cu concentration. The magnetic measurements show a contrasting saturation magnetization and coercivity (HC) for the case of samples having lower (x ≤ 3) and higher (x > 3) Cu content in Fe–Co alloys. These variations are explained on the basis of crystallite size and strain variations in the samples during milling. Present results indicate that a nonmagnetic inc...
Advanced Powder Technology, 2014
Fe 1Àx Co x (x = 0.1, 0.15, 0.2, 0.25, 0.3 and 0.5) powders were prepared by different milling-annealing treatments, and magnetic properties were investigated based on microstructure. Elevated heating times led to an increase in crystallite size, and decrease in lattice parameter. Up to 20 min annealing, series 3 powders showed a decrease in microstrain 2.5 times more than series 2. The coercivity (H C ) of 1-step milled and 60 min annealed Fe 50 Co 50 alloys decreased rigorously from 60 Oe to 19 Oe due to strain relief (from 0.3% to 0.08%) and grain growth (from 30 nm to 40 nm). For series 2 alloys, the H C (up to 60 min heating) increased from 72 Oe to 90 Oe, and decreased (up to 100 min heating) to 70 Oe. Compared to series 1, extra milling treatment of series 2 causes an increase in magnetization saturation (M S ) due to completion of alloying and grain refinement. Also, compared to series 2, extra annealing treatment for series 3 resulted in larger values of M S caused by stain relief.
Magnetic and microstructural properties of the mechanically alloyed Fe57Co21Nb7B15 powder mixture
Materials Chemistry and Physics, 2012
Partially amorphous Fe 57 Co 21 Nb 7 B 15 powder mixture was prepared by mechanical alloying in a high energy planetary ball-mill under argon atmosphere. Thermal stability, magnetic properties, structural and morphological changes during the milling process were followed by differential scanning calorimetry, vibrating sample magnetometry, X-ray diffraction and scanning electron microscopy. A duplex nanostructure of Fe(Co) and Fe-boride nanocrystals within an amorphous matrix is achieved on further milling time. Depending on the structural state of the milled powders, two or several overlapping exothermic peaks over the temperature range 100-700 • C were revealed in the DSC scans. The saturation magnetization and coercivity values are of about 111 emu g −1 and 59 Oe, respectively, after 96 h of milling.
Journal of Magnetism and Magnetic Materials, 2011
The Fe 48 Co 48 V 4 alloy was synthesized in a planetary high-energy ball-mill under an argon atmosphere. The structure, microstructure and magnetic properties of the mechanically alloyed powders were investigated by X-ray diffraction, Scanning Electron Microscopy and a Vibration Sample Magnetometer, respectively. During the mechanical alloying of Fe 48 Co 48 V 4 , inter-metallic Co 3 V appears. The lattice parameter decreases up to 55 h of milling time with an oscillation and then increases from 55 to 125 h of milling time. The coercivity increases during the milling treatment from 49 to 58 Oe. The saturation magnetization has some fluctuations during the milling treatment and finally reaches $ 190 emu/g at 125 h.
Magnetic and structural properties of as-milled and heat-treated bcc-Fe70Cu30 alloy
Journal of Magnetism and Magnetic Materials, 1995
A ferromagnetic solid solution with a nomina] atomic composition FeroCUr~ and a body-cen~ structure has been obtained by high-energy ball milling. The decomposition of the system is monitored by X-ray diffraction (XRD), measurements and M~ssbauer spectroscopy. According to XRDo for heating lcmpe.~tures below 723 K there is only a bcc ph.".~e in the material, while fvr heating temperatures above 723 K a new phase, with a fcc structure, appears, suggesting lha~ the solid solution has decomposc'd into bce-Fe and fcc-Cu. However, the magnetic behavior observed during the decomposition process indicates that this evolution is more complex than the simple deeomposition into the equilibrmm phases. This behavior can be summarized in two points: (1) a decrease in the ma~-tization at 5 K, and (2) dra~Ii¢ cha~'cs in the coercive field with the thermal treatment, soft magnetic behavior for the matc~"ial in the as-milled sta~e, ~a~g~ netism for low heating temperatures and a hardening of the mat~al ~ to above 723 K, for which the va|~es of the coercive field at room temperature are several times higher than those for the as-milled sampte. The Mtissbat~r st~ctrosc~y performed at room temperature shows thai for the heat-u~ated samples ~i~ Fe atoms are in two differem phases: a ferromagnetic phase, which evolves to bcc-Fe, and a paramag,~et~: phase.
Powder Metallurgy and Metal Ceramics, 2017
The effect of milling time and addition of elements on the microstructure, magnetic and mechanical properties of the Fe-xCo (x = 0, 5, 10, and 20 wt.%) matrix nanocomposite reinforced with 40 wt.%Al2O3 during mechanical alloying is examined. Fe-Al2O3 and Fe-Co-Al2O3 alloys are milled for 5,15, 20, and 30 h and 20 h, respectively. The balance between the welding and fracturing and asteady-state situation is found out in the Fe-Co-40 wt.% Al2O3 nanocomposite after 20 h, due to theCo introduction into the Fe matrix, but not in the Fe-Al2O3 nanocomposite. After 30 h of milling, theaverage crystallite size was 5 nm in the Fe matrix. The lattice strain increased to ~0.64% in the Fematrix after 30 h of milling and in the binary Fe-20 wt.% Co matrix after 20 h of milling; theaverage crystallite size was 3 nm. The lattice strain increased to ~0.56% for the Fe-20 wt.% Comatrix after 20 h of milling. The coercive field (Hc) increased from 6.407 to 82.027 Oe, while thesaturation magnetization (Ms) decreased from 20.732 to 15.181 emu/g in the Fe matrix duringmilling. The Hc and Ms are maximum for the binary matrix (20 and 10% Co, respectively).
Journal of Magnetism and Magnetic Materials, 2010
Properties of FeCo nanocrystalline intermetallic powders prepared by salt-matrix hydrogen reduction of a milled Fe 2O 3-Co 3O 4 mixture were investigated. The product of 72 ks ball-milling at 350 rpm was CoFe 2O 4 nanopowder. Reduction of this powder for 3.6 ks by hydrogen at 750 °C resulted in the formation of Fe 0.67Co 0.33 stoichiometric compound. Scanning electron microscopy, electron dispersive spectrometry, X-ray diffraction and vibrating sample magnetometry were used to characterize the nanopowder. Using a salt-matrix (NaCl as a dispersion medium) resulted in the decrease of the reduction temperature and improvement of the morphology and magnetic properties of the nanopowder. Dispersion of the ball-milled product in Hexan resulted in further improvements of the magnetic properties.