scholarly journals Influence of Milling Time on the Homogeneity and Magnetism of a Fe70Zr30 Partially Amorphous Alloy: Distribution of Curie Temperatures

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 490
Author(s):  
Alejandro F. Manchón-Gordón ◽  
Jhon J. Ipus ◽  
Javier S. Blázquez ◽  
Clara F. Conde ◽  
Alejandro Conde
Keyword(s):  
Amorphous Alloy ◽  
Crystal Size ◽  
Milling Time ◽  
Magnetocrystalline Anisotropy ◽  
Amorphous Matrix ◽  
Magnetic Behavior ◽  
Magnetic Response ◽  
Soft Magnetic ◽  
Mechanically Alloyed ◽  
Curie Temperatures

In this work, the mechanically alloyed Fe70Zr30 (at. %) composition has been used to study the influence of milling time on its homogeneity and magnetic properties. The microstructure and Fe environment results show the formation of an almost fully amorphous alloy after 50 h of milling in a mixture of pure 70 at. % Fe and 30 at. % Zr. The soft magnetic behavior of the samples enhances with the increase of the milling time, which is ascribed to the averaging out of the magnetocrystalline anisotropy as the crystal size decreases and the amorphous fraction increases. The formation of a non-perfectly homogenous system leads to a certain compositional heterogeneity, motivating the existence of a distribution of Curie temperatures. The parameters of the distribution (the average Curie temperature, T C ¯ , and the broadening of the distribution, ∆ T C ) have been obtained using a recently reported procedure, based on the analysis of the approach towards the saturation curves and the magnetocaloric effect. The decrease of ∆ T C and the increase of T C ¯ with the milling time are in agreement with the microstructural results. As the remaining α-Fe phase decreases, the amorphous matrix is enriched in Fe atoms, enhancing its magnetic response.

Synthesis and Characterization of Fe-Co Nanocrystalline Alloys

2004 ◽  
Vol 821 ◽  
Author(s):  
Mohammad Mujahid ◽  
Jie Zhu
Keyword(s):  
Crystal Size ◽  
Magnetic Behavior ◽  
Internal Strain ◽  
Soft Magnetic Materials ◽  
X Ray Diffraction ◽  
Soft Magnetic ◽  
Particle Size And Morphology ◽  
Size And Morphology ◽  
Curie Temperatures

AbstractNanostructured alloys have great potential as soft magnetic materials. In particular, nanocrystalline Fe-Co based alloys are believed to be good candidates for imparting improved magnetic behavior in terms of higher permeability, lower coercivity, reduced hysteresis losses and higher Curie temperatures. In the present work, Fe-50at.%Co alloy powders have been prepared using mechanical alloying (MA) in a planetary ball mill under controlled environment. The particle size and morphology of MA powders was investigated using scanning electron microscopy. The crystal size and internal strain was measured using X-ray diffraction. It has been shown that the crystal size could be reduced down to less than 15 nm in these alloys. Finally, the influence of grain size and internal strain on the magnetic properties has been discussed.

Two milling time regimes in the evolution of magnetic anisotropy of mechanically alloyed soft magnetic powders

2011 ◽  
Vol 509 (5) ◽  
pp. 1407-1410 ◽  
Author(s):  
J.J. Ipus ◽  
J.S. Blázquez ◽  
V. Franco ◽  
C.F. Conde ◽  
A. Conde
Keyword(s):  
Magnetic Anisotropy ◽  
Milling Time ◽  
Soft Magnetic ◽  
Mechanically Alloyed

Temperature dependence of the soft magnetic character of Fe73.5Cu1Nb3Si13.5B9 amorphous and nanocrystalline alloys

2003 ◽  
Vol 18 (5) ◽  
pp. 1035-1038 ◽  
Author(s):  
J. Gonzáz
Keyword(s):  
Amorphous Alloy ◽  
Current Density ◽  
Curie Point ◽  
Amorphous Matrix ◽  
Body Centered Cubic ◽  
Soft Magnetic ◽  
Current Densities ◽  
Two Phases ◽  
Residual Amorphous Matrix ◽  
Magnetic Hardness

Results on microstructure and coercivity of current-annealed Fe73.5Cu1Nb3Si13.5B9 amorphous alloy treated at different current densities (12–56 A/mm2) and duration (0.5–720 min) are presented. Saturation magnetization and coercivity dependencies with the current density of the nanocrystalline samples is explained by considering the presence of two phases: nanocrystals of Fe(Si) body-centered cubic (bcc) grains and the residual amorphous matrix. An increase in the magnetic hardness observed when the sample was heated by current densities, giving rise to an increase in the sample temperature above the Curie point of the residual amorphous matrix, could be ascribed to exchange and dipolar decoupling of the Fe(Si)-bcc grains.

Magnetic Properties of Nanocrystalline Fe50Co50 Powders

2003 ◽  
Vol 788 ◽  
Author(s):  
Shashishekar Basavaraju ◽  
Ian Baker
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Magnetic Force ◽  
Milling Time ◽  
Magnetic Behavior ◽  
High Energy ◽  
Soft Magnetic ◽  
Scanning Calorimetry ◽  
High Energy Ball Mill ◽  
Energy Ball

ABSTRACTNanocrystalline stoichiometric FeCo powders were prepared by mechanically alloying elemental Fe and Co powders using a high-energy ball mill. The microstructural evolution was studied as a function of milling time and subsequent annealing using X-ray diffractometry and differential scanning calorimetry. The magnetic behavior of the specimens was characterized using a vibrating sample magnetometer and a magnetic force microscope. A reduction in grain size coupled with an increase in coercivity was observed as function of milling time. The smallest grain size of 4 nm, which exhibited a coercivity of 122 Oe and magnetization of 2 T at room temperature, was obtained after 240 h of milling. The reduction in grain size during milling was not accompanied by enhanced soft magnetic properties.

Thermomagnetic Analysis of the Crystallization in Soft Magnetic Nanocrystalline Alloys

2020 ◽  
Vol 846 ◽  
pp. 67-71
Author(s):  
Vladimir S. Tsepelev ◽  
Yuri N. Starodubtsev ◽  
K.M. Wu ◽  
Nadezhda P. Tsepeleva
Keyword(s):  
Amorphous Matrix ◽  
Chemical Elements ◽  
Amorphous State ◽  
Simultaneous Recording ◽  
Soft Magnetic ◽  
Crystallization Peak ◽  
Thermomagnetic Analysis ◽  
The Core ◽  
Si Nanocrystals ◽  
Curie Temperatures

In this work, we investigated the dynamics of nanocrystallization from the amorphous state of the Fe72.5Cu1Nb2Mo1.5Si14B9 alloy together with magnetic phase transformations. The thermomagnetic analysis was performed with the simultaneous recording of the temperature inside the core by a thermocouple and the inductance of the winding wound over the core. It was found that the permeability of the core after the crystallization peak first increases rapidly, and then decreases and stabilizes at some level. Permeability growth begins at a temperature that coincides with the Curie point of the Fe80Si20 solid solution. A decrease in permeability was associated with stabilization of the structure of the amorphous and crystalline phases upon cooling. With decreasing temperature, the active redistribution of chemical elements is suppressed, and silicon atoms occupy a stable position in the crystal lattice of iron. Nanocrystalline cores have different Curie temperatures in the state after the peak of crystallization and 300 seconds after the peak. This indicates the continuation of the diffusion of silicon from the amorphous matrix into Fe-Si nanocrystals for some time after the crystallization peak.

Room Temperature Magnetic Response of Sputter Deposited TbDyFe Films as a Function of the Deposition Parameters

2012 ◽  
Vol 18-19 ◽  
pp. 235-239 ◽  
Author(s):  
L. Rebouta ◽  
P. Martins ◽  
Senentxu Lanceros-Méndez ◽  
Jose Manuel Barandiaran ◽  
Jon Gutiérrez ◽  
...  
Keyword(s):  
Room Temperature ◽  
Magnetic Behavior ◽  
Phase System ◽  
Magnetic Response ◽  
Soft Magnetic ◽  
Two Phase ◽  
Deposition Parameters ◽  
Oxide Phases ◽  
Small Grains ◽  
Sputter Deposited

Magnetostrictive thin films of the ternary compound (TbyDy1-y)xFe1-x have been prepared by magnetron sputtering from a Terfenol D target onto both room-temperature and high-temperature substrates (TS<550 °C). The aim is to select the deposition parameters of this highly magnetostrictive material in order to optimize its magnetic response. Films prepared on room-temperature substrates were amorphous and those deposited at high temperatures have a microstructure consisting of small grains of RFe2 compound and some RE oxide phases. Deposition temperatures around 550 °C promotes in-plane orientation of (220) and (311) planes of RFe2 phase. The magnetization measurements performed at room temperature showed that depending on the processing conditions the material changes from a soft magnetic behavior with perpendicular anisotropy to a two phase system with both hard and soft magnetic phases.

scholarly journals Effect of Milling Parameters on the Development of a Nanostructured FCC–TiNb15Mn Alloy via High-Energy Ball Milling

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1225
Author(s):  
Cristina García-Garrido ◽  
Ranier Sepúlveda Sepúlveda Ferrer ◽  
Christopher Salvo ◽  
Lucía García-Domínguez ◽  
Luis Pérez-Pozo ◽  
...  
Keyword(s):  
Mechanical Alloying ◽  
Ball Mill ◽  
Milling Time ◽  
High Energy ◽  
Planetary Mill ◽  
Nominal Composition ◽  
Mechanically Alloyed ◽  
Milling Parameters ◽  
Energy Ball ◽  
Full Conversion

In this work, a blend of Ti, Nb, and Mn powders, with a nominal composition of 15 wt.% of Mn, and balanced Ti and Nb wt.%, was selected to be mechanically alloyed by the following two alternative high-energy milling devices: a vibratory 8000D mixer/mill® and a PM400 Retsch® planetary ball mill. Two ball-to-powder ratio (BPR) conditions (10:1 and 20:1) were applied, to study the evolution of the synthesized phases under each of the two mechanical alloying conditions. The main findings observed include the following: (1) the sequence conversion evolved from raw elements to a transitory bcc-TiNbMn alloy, and subsequently to an fcc-TiNb15Mn alloy, independent of the milling conditions; (2) the total full conversion to the fcc-TiNb15Mn alloy was only reached by the planetary mill at a minimum of 12 h of milling time, for either of the BPR employed; (3) the planetary mill produced a non-negligible Fe contamination from the milling media, when the highest BPR and milling time were applied; and (4) the final fcc-TiNb15Mn alloy synthesized presents a nanocrystalline nature and a partial degree of amorphization.

Soft magnetic properties of the Fe72Co10Nb6B12 amorphous alloy

2006 ◽  
Vol 423 (1-2) ◽  
pp. 77-80 ◽  
Author(s):  
A. Chrobak ◽  
G. Haneczok ◽  
P. Kwapuliński ◽  
D. Chrobak ◽  
Z. Stokłosa ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Amorphous Alloy ◽  
Soft Magnetic Properties ◽  
Soft Magnetic

Ball milling for the formation of nanocrystalline intermetallic compounds from Ni-Ti elemental powders

2018 ◽  
Vol 27 (5-6) ◽  
Author(s):  
Pardeep Sharma
Keyword(s):  
Intermetallic Compounds ◽  
Milling Time ◽  
Lattice Strain ◽  
Research Work ◽  
High Energy ◽  
Mechanically Alloyed ◽  
Nano Crystalline ◽  
High Energy Ball Mill ◽  
Productive Process ◽  
Energy Ball

AbstractIn the present research work nickel (Ni) and titanium (Ti) elemental powder with an ostensible composition of 50% of each by weight were mechanically alloyed in a planetary high energy ball mill in diverse milling circumstances (10, 20, 30 and 60 h). The inspection exposed that increasing milling time leads to a reduction in crystallite size, and after 60 h of milling, the Ti dissolved in the Ni lattice and the NiTi (B2) phase was obtained. The lattice strain of ball milled mixtures augmented from 0.15 to 0.45 at 60 h milling. With increase in milling time the morphology of pre-alloyed powder changed from lamella to globular. Annealing of as-milled powders at 1100 K for 800 s led to the formation of NiTi (B19′), grain growth and the release of internal strain. The result indicated that this technique is a powerful and highly productive process for preparing NiTi intermetallic compounds with a nano-crystalline structure and appropriate morphology.

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