scholarly journals Four-step eco-friendly energy efficient recycling of contaminated Nd2Fe14B sludge and coercivity enhancement by reducing oxygen content

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Syed Kamran Haider ◽  
Dongsoo Kim ◽  
Young Soo Kang
Keyword(s):  
Magnetic Properties ◽  
Boric Acid ◽  
Oxygen Content ◽  
Energy Efficient ◽  
Residual Carbon ◽  
Green Process ◽  
Chemical Methods ◽  
Step Process ◽  
Calciothermic Reduction ◽  
Co Precipitation

AbstractComplete recycling of Nd2Fe14B sludge by chemical methods has gained significance in recent years, however, it is not easy to recycle highly contaminant sludge and obtain product with good magnetic properties. Herein we report a simple four-step process to recycle the Nd2Fe14B sludge containing ~ 10% of contaminants. Sludge was leached in H2SO4 and selectively co-precipitated in two steps. In the first co-precipitation, Al3+ and Cu2+ were removed at pH 6. Thereafter, in the second co-precipitation Fe2+ and RE3+ sulfates were converted to the Fe and RE hydroxides. By annealing at 800 °C RE and Fe hydroxides precipitates were converted to the oxides and residual carbon was oxidized to CO2. After the addition of boric acid, Fe and RE oxides were reduced and diffused to the (Nd-RE)2Fe14B by calciothermic reduction diffusion. Removal of CaO by washing with D.I. water in glove box reduced the oxygen content (~ 0.7%), improved crystallinity and enhanced the magnetic properties significantly. Coercivity increased more than three times (from 242.71 to 800.55 kA/m) and Mr value was also enhanced up to more than 20% (from 0.481 to 0.605 T). In this green process Na2SO4 and Ca(OH)2 were produced as by-product those are non-hazardous and were removed conveniently.

scholarly journals Impact of Iron on the Fe–Co–Ni Ternary Nanocomposites Structural and Magnetic Features Obtained via Chemical Precipitation Followed by Reduction Process for Various Magnetically Coupled Devices Applications

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 341
Author(s):  
Tien Hiep Nguyen ◽  
Gopalu Karunakaran ◽  
Yu.V. Konyukhov ◽  
Nguyen Van Minh ◽  
D.Yu. Karpenkov ◽  
...  
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Reduction Process ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Magnetic Characteristics ◽  
Reduction Temperature ◽  
Fe Content ◽  
Magnetic Features ◽  
Co Precipitation

This paper presents the synthesis of Fe–Co–Ni nanocomposites by chemical precipitation, followed by a reduction process. It was found that the influence of the chemical composition and reduction temperature greatly alters the phase formation, its structures, particle size distribution, and magnetic properties of Fe–Co–Ni nanocomposites. The initial hydroxides of Fe–Co–Ni combinations were prepared by the co-precipitation method from nitrate precursors and precipitated using alkali. The reduction process was carried out by hydrogen in the temperature range of 300–500 °C under isothermal conditions. The nanocomposites had metallic and intermetallic phases with different lattice parameter values due to the increase in Fe content. In this paper, we showed that the values of the magnetic parameters of nanocomposites can be controlled in the ranges of MS = 7.6–192.5 Am2/kg, Mr = 0.4–39.7 Am2/kg, Mr/Ms = 0.02–0.32, and HcM = 4.72–60.68 kA/m by regulating the composition and reduction temperature of the Fe–Co–Ni composites. Due to the reduction process, drastic variations in the magnetic features result from the intermetallic and metallic face formation. The variation in magnetic characteristics is guided by the reduction degree, particle size growth, and crystallinity enhancement. Moreover, the reduction of the surface spins fraction of the nanocomposites under their growth induced an increase in the saturation magnetization. This is the first report where the influence of Fe content on the Fe–Co–Ni ternary system phase content and magnetic properties was evaluated. The Fe–Co–Ni ternary nanocomposites obtained by co-precipitation, followed by the hydrogen reduction led to the formation of better magnetic materials for various magnetically coupled device applications.

scholarly journals Enhancement of anisotropy energy of SmCo5 by ceasing the coupling at 2c sites in the crystal lattice with Cu substitution

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Syed Kamran Haider ◽  
Hieu Minh Ngo ◽  
Dongsoo Kim ◽  
Young Soo Kang
Keyword(s):  
Crystal Lattice ◽  
Energy Efficient ◽  
Magnetic Particles ◽  
Anisotropy Energy ◽  
Ternary Alloys ◽  
Total Cost ◽  
Additional Weight ◽  
Cu Substitution ◽  
Decoupling Effect ◽  
Co Precipitation

AbstractSmCo5 and SmCo5−xCux magnetic particles were produced by co-precipitation followed by reduction diffusion. HRTEM confirmed the Cu substitution in the SmCo5 lattice. Non-magnetic Cu was substituted at “2c” site in the SmCo5 crystal lattice and effectively stopped the coupling in its surroundings. This decoupling effect decreased magnetic moment from SmCo5 (12.86 μB) to SmCo4Cu (10.58 μB) and SmCo3Cu2 (7.79 μB) and enhanced anisotropy energy from SmCo5 (10.87 Mega erg/cm3) to SmCo4Cu (14.05 Mega erg/cm3) and SmCo3Cu2 (14.78 Mega erg/cm3). Enhancement of the anisotropy energy increased the coercivity as its values for SmCo5, SmCo4Cu and SmCo3Cu2 were recorded as 4.5, 5.97 and 6.99 kOe respectively. Being six times cheaper as compared to Co, substituted Cu reduced the price of SmCo3Cu2 up to 2%. Extra 15% Co was added which not only enhanced the Mr value but also reduced the 5% of the total cost because of additional weight added to the SmCo3Cu2. Method reported in this work is most energy efficient method on the synthesis of Sm–Co–Cu ternary alloys until now.

Fe films grown on GaAs(110) in a two-step process: Improved structural and magnetic properties

2008 ◽  
Vol 92 (19) ◽  
pp. 193102 ◽  
Author(s):  
L. Winking ◽  
M. Wenderoth ◽  
J. Homoth ◽  
S. Siewers ◽  
R. G. Ulbrich
Keyword(s):  
Magnetic Properties ◽  
Step Process ◽  
Structural And Magnetic Properties

Structural, morphological, and magnetic properties of ZnxCo1-xFe2O4 (0 ≤ x ≤ 1) prepared using a chemical co-precipitation method

2018 ◽  
Vol 44 (17) ◽  
pp. 20782-20789 ◽  
Author(s):  
Rohit R. Powar ◽  
Varsha D. Phadtare ◽  
Vinayak G. Parale ◽  
Hyung-Ho Park ◽  
Sachin Pathak ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Precipitation Method ◽  
Co Precipitation

scholarly journals LOW-TEMPERATURE SYNTHESIS OF SUPERPARAMAGNETIC Zn0.8Ni0.2Fe2O4 FERRITE NANOPARTICLES

2018 ◽  
Vol 56 (1) ◽  
pp. 31
Author(s):  
Luong Thi Quynh Anh ◽  
Nguyen Van Dan ◽  
Do Minh Nghiep
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Oleic Acid ◽  
Low Temperature ◽  
Coercive Force ◽  
Saturation Magnetization ◽  
Ferrite Nanoparticles ◽  
Low Temperature Synthesis ◽  
Temperature Synthesis ◽  
Co Precipitation

The crystalline nanoparticles of Ni0.2Zn0.8Fe2O4 ferrite were synthesized by chemical co-precipitation with precursor concentration of 0.1M, then modified by 0.25M solution of oleic acid in pentanol, finally heated at temperatures 120, 140, 160 and 180oC for 6h in autoclave. The XRD, EDS and TEM confirmed that all of samples are crystalline and their particle size are 6, 6.5, 7 and 8 nm. The magnetic properties showed that the coercive force, the remanence of samples are about zero, the saturation magnetization Ms has values from 14.20 to 27.12 emu/g.

Composition and magnetic properties of cobalt ferrite nano-particles prepared by the co-precipitation method

2010 ◽  
Vol 322 (21) ◽  
pp. 3470-3475 ◽  
Author(s):  
Yue Zhang ◽  
Zhi Yang ◽  
Di Yin ◽  
Yong Liu ◽  
ChunLong Fei ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Cobalt Ferrite ◽  
Nano Particles ◽  
Precipitation Method ◽  
Co Precipitation

Nanometer size effect on the structure and magnetic properties of high oxygen content ferromagnetic PrMnO3+δ nanoparticles

2010 ◽  
Vol 108 (11) ◽  
pp. 113901 ◽  
Author(s):  
T. Zhang ◽  
Y. Z. Fang ◽  
M. Dressel ◽  
X. P. Wang ◽  
Q. F. Fang
Keyword(s):  
Magnetic Properties ◽  
Size Effect ◽  
Oxygen Content ◽  
High Oxygen ◽  
High Oxygen Content ◽  
Nanometer Size
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