scholarly journals Magnetic Properties of SmCo5 + 10 wt% Fe Exchange-Coupled Nanocomposites Produced from Recycled SmCo5

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1308 ◽  
Author(s):  
Arnab Chakraborty ◽  
Răzvan Hirian ◽  
Gregor Kapun ◽  
Viorel Pop
Keyword(s):  
Heat Treatment ◽  
Exchange Coupling ◽  
Permanent Magnets ◽  
High Energy ◽  
Raw Material ◽  
Energy Ball ◽  
Hydrogen Decrepitation ◽  
Energy Products ◽  
First Time ◽  
Recycled Material

Nanostructured alloy powders of SmCo5 + 10 wt% Fe obtained using recycled material were studied for the first time. The SmCo5 precursor was obtained from commercial magnets recycled by hydrogen decrepitation. The results were compared with identically processed samples obtained using virgin SmCo5 raw material. The samples were synthesized by dry high-energy ball-milling and subsequent heat treatment. Robust soft/hard exchange coupling was observed—with large coercivity, which is essential for commercial permanent magnets. The obtained energy products for the recycled material fall between 80% and 95% of those obtained when using virgin SmCo5, depending on milling and annealing times. These results further offer viability of recycling and sustainability in production. These powders and processes are therefore candidates for the next generation of specialized and nanostructured exchange-coupled bulk industrial magnets.

A Study of Exchange-Coupling Effect on Nd2Fe14B / α-Fe Forming Core/Shell Shape

2007 ◽  
Vol 119 ◽  
pp. 147-150 ◽  
Author(s):  
Chang Woo Kim ◽  
Young Hwan Kim ◽  
Don Keun Lee ◽  
In Chul Jeong ◽  
Hae Woong Kwon ◽  
...  
Keyword(s):  
Exchange Coupling ◽  
Ball Mill ◽  
Coupling Effect ◽  
Chemical Reduction ◽  
High Energy ◽  
Shell Shape ◽  
Core Shell ◽  
High Energy Ball Mill ◽  
Energy Ball ◽  
Mill Process

We report the core/shell type as the interesting one of the various techniques to prepare exchange-coupled permanent magnet. In this study, the exchange-coupled Nd2Fe14B/α-Fe was prepared by high energy ball mill process and chemical reduction. Nd15Fe77B8 powder prepared by high energy ball mill process was coated with α-Fe nanoparticle by chemical reduction. α-Fe nanoparticle on the ball milled Nd15Fe77B8 was synthesized by chemical reduction with borohydride as a reducing agent in aqueous solution. After annealing, Nd2Fe14B/α-Fe forming core/shell shape has exchange-coupling effect and was identified by using XRD, FE-SEM, VSM, TMA and EDX.

On sinterability of nanostructured W produced by high-energy ball milling

2007 ◽  
Vol 22 (5) ◽  
pp. 1200-1206 ◽  
Author(s):  
R. Malewar ◽  
K.S. Kumar ◽  
B.S. Murty ◽  
B. Sarma ◽  
S.K. Pabi
Keyword(s):  
Sintered Density ◽  
Sintering Temperature ◽  
High Energy ◽  
Deformation Bands ◽  
Dramatic Decrease ◽  
Powder Charge ◽  
Grinding Media ◽  
Energy Ball ◽  
High Level ◽  
First Time

The present investigation reports for the first time a dramatic decrease in the sintering temperature of elemental W from the conventional temperature of ≥2500 °C to the modest temperature range of 1700–1790 °C by making the W powder nanostructured through high-energy mechanical milling (MM) prior to sintering. The crystallite size of the initial W powder charge with a particle size of 3–4 μm could be brought down to 8 nm by MM for 5 h in WC grinding media. Further milling resulted in a high level of WC contamination, which apparently was due to work hardening and the grain refinement of W. A sintered density as high as 97.4% was achieved by sintering cold, isostatically pressed nanocrystalline (8 nm) W powder at 1790 °C for 900 min. The microstructure of the sintered rods showed the presence of deformation bands, but no cracks, within a large number of W grains. The mechanical properties, when compared with the hardness and elastic modulus, of the sintered nano-W specimen were somewhat superior to those reported for the conventional sintered W.

Preparation of Nb–25Si, Nb–37.5Si, Nb–66.6Si powders by high-energy ball milling and subsequent heat treatment

2007 ◽  
Vol 434-435 ◽  
pp. 509-513 ◽  
Author(s):  
Bruno Bacci Fernandes ◽  
Erika Coaglia Trindade Ramos ◽  
Gilbert Silva ◽  
Alfeu Saraiva Ramos
Keyword(s):  
Heat Treatment ◽  
Ball Milling ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Subsequent Heat Treatment ◽  
Energy Ball

A Comparative Study between Low and High-Energy Milling Processes for the Production of HD PrFeCoBNb Sintered Magnets

2008 ◽  
Vol 591-593 ◽  
pp. 114-119 ◽  
Author(s):  
E.A. Périgo ◽  
E.P. Soares ◽  
Hidetoshi Takiishi ◽  
C.C. Motta ◽  
Rubens Nunes de Faria Jr.
Keyword(s):  
Ball Milling ◽  
Permanent Magnets ◽  
High Energy ◽  
Maximum Energy ◽  
Maximum Energy Product ◽  
High Energy Milling ◽  
Energy Product ◽  
Energy Processing ◽  
Hydrogen Decrepitation ◽  
High Degree

Roller-ball milling (RBM) or planetary ball milling (PBM) have been used together with the hydrogen decrepitation (HD) process to produce sintered permanent magnets based on a mixture of Pr16Fe76B8 and Pr14.00Fe63.90Co16.00B6.00Nb0.10 magnetic alloys. Five distinct compositions have been studied comparing low- and high-energy milling. Magnets with a particular composition and prepared using these two routes exhibited similar magnetic properties. Modifications have been carried out in the procedure of the HD stage for PBM in order to guarantee a high degree of crystallographic alignment. Pr15.00Fe69.95Co8.00B7.00Nb0.05 magnets showed the best maximum energy product for both processing routes (~ 247 kJm-3). A significant reduction in the milling time (93%) has been achieved with high-energy processing, the greatest advantage over the low-energy route.

Synthesis and Characterization of Electromagnetic Material Based On Composite of Barium M-Ferrite and Zinc Oxide

2018 ◽  
pp. 78-82
Author(s):  
Verryon Harahap ◽  
Syahrul Humaidi ◽  
Perdamean Sebayang
Keyword(s):  
Zinc Oxide ◽  
Magnetic Properties ◽  
High Energy ◽  
Lattice Parameter ◽  
Milling Process ◽  
Raw Material ◽  
Wet Milling ◽  
Hexagonal Crystal ◽  
Milling Method ◽  
Energy Products

The making of composites BaFe12O19/ZnO has been done with Wet Milling method used media toluene. Barium M-Ferrit as a matrix and Zinc Oxide as a filler used as the main raw material for composite manufacturing. The milling process of Barium M-Ferrit was done for 12 hours using the High Energy Milling (HEM). Furthermore, the calcination process used furnace at 900 ° C for 4 hours. While Zinc Oxide is milled for 3 hours and calcined at a temperature of 500 oC for 3 hours. The results of Barium M-Ferrit and zinc Oxide mixed using wet milling touluene media for 15 minutes and dried for 1 hour at 200 oC. X-ray diffraction (XRD) showed that BaFe12O19 as a matrix and ZnO as filler with hexagonal crystal structure was formed and the peak showed a single phase, where each BaFe12O19 lattice parameter a = 5.8930 Å, c = 23.1940 Å and ZnO lattice parameter a = 3.2533 Å, c = 5.2073 Å. Characterization Vibrating Sample Magnetometer (VSM) obtained the value of magnetic properties BaFe12O19 powder (matrix) obtained (Ms) magnetic saturation 54.03 emu/g, (Mr) magnet remanent 33.06 emu/g, (Hcj) coercivity 2943 Oe and (BHmax) product energy 190 kGOe and Zinc Oxide as filler values (Ms) magnet saturation 7.84 emu / g, (Mr) magnet remanent 1.27 emu/g, (Hcj) coercivity 152.4 Oe and (BHmax) energy products 10 kGOe. The results of XRD on 50% mass of composites ZnO additions using match software have two phases, namely the presence of ZnO and BaFe12O19 phases which indicate that heterogeneous structures with hexagonal crystal structures. Composite magnetic properties obtained by adding 50% mass of ZnO were (Mr) magnet 39.40 emu/ g, coercivity 2728 Oe, (BHmax) product energy 110 kGOe and for composites 75% mass addition ZnO remanent 39.36 emu/g with coefficient of 1365 Oe and ( BHmax) product energy was 60 kGOe.

NdFeB/αFe Nanocomposite Permanent Magnets with Enhanced Properties Prepared by Spark Plasma Sintering

2011 ◽  
Vol 672 ◽  
pp. 229-232
Author(s):  
Marian Grigoraş ◽  
M. Lostun ◽  
Nicoleta Lupu ◽  
Horia Chiriac
Keyword(s):  
Spark Plasma Sintering ◽  
Permanent Magnets ◽  
High Energy ◽  
Maximum Energy ◽  
Maximum Energy Product ◽  
Energy Product ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Energy Ball ◽  
Melt Spun Ribbons

Nanocomposite NdFeB/αFe magnets were obtained by spark plasma sintering technique using high energy ball-milled Nd-Fe-B melt-spun ribbons mixed in different weight ratios with Fe commercial powders. The remanence of SPS nanocomposite magnets increases with the Fe powders content from 6.1 for 4 wt.% Fe to 6.4 kG for 5 wt.% Fe, while the estimated maximum energy product is also increased from 9.0 to 10.6 MGOe.

scholarly journals Combustion of Titanium–Carbon Black High-Energy Ball-Milled Mixtures in Nitrogen: Formation of Titanium Carbonitrides at Atmospheric Pressure

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1810
Author(s):  
Michail A. Korchagin ◽  
Dina V. Dudina ◽  
Alexander I. Gavrilov ◽  
Boris B. Bokhonov ◽  
Natalia V. Bulina ◽  
...  
Keyword(s):  
Carbon Black ◽  
Atmospheric Pressure ◽  
Single Phase ◽  
High Energy ◽  
Nitrogen Atmosphere ◽  
Titanium Carbonitrides ◽  
Carbon Black Powder ◽  
High Temperature Synthesis ◽  
Energy Ball ◽  
First Time

In this work, titanium carbonitrides were synthesized by self-propagating high-temperature synthesis (SHS) in nitrogen. For the first time, the synthesis of titanium carbonitrides by combustion was realized in nitrogen at atmospheric pressure. The synthesis was carried out by subjecting high-energy ball-milled titanium–carbon black powder mixtures to combustion in a nitrogen atmosphere. The influence of the ball milling time on the phase composition of the products of SHS conducted in the Ti+0.3C reaction mixture was studied. It was found that the titanium–carbon black mixtures need to be milled for a certain period of time for the combustion synthesis to yield a single-phase carbonitride product.

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