scholarly journals Blending Powder Process for Recycling Sintered Nd-Fe-B Magnets

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3049
Author(s):  
Pavel A. Prokofev ◽  
Natalia B. Kolchugina ◽  
Katerina Skotnicova ◽  
Gennady S. Burkhanov ◽  
Miroslav Kursa ◽  
...  
Keyword(s):  
Permanent Magnets ◽  
Boundary Diffusion ◽  
Resource Constraints ◽  
Magnetic Phase ◽  
Earth Metal ◽  
Core Shell ◽  
Recycling Process ◽  
Composition Inhomogeneity ◽  
Core Shell Structure ◽  
Hydrogen Decrepitation

The wide application of Nd-Fe-B permanent magnets, in addition to rare-earth metal resource constraints, creates the necessity of the development of efficient technologies for recycling sintered Nd-Fe-B permanent magnets. In the present study, a magnet-to-magnet recycling process is considered. As starting materials, magnets of different grades were used, which were processed by hydrogen decrepitation and blending the powder with NdHx. Composition inhomogeneity in the Nd2Fe14B-based magnetic phase grains in the recycled magnets and the existence of a core-shell structure consisting of a Nd-rich (Dy-depleted) core and Nd-depleted (Dy-enriched) shell are demonstrated. The formation of this structure results from the grain boundary diffusion process of Dy that occurs during the sintering of magnets prepared from a mixture of Dy-free (N42) and Dy-containing magnets. The increase in the coercive force of the N42 magnet was shown to be 52%. The simultaneous retention of the remanence, and even its increase, were observed and explained by the improved isolation of the main magnetic phase grains as well as their alignment.

scholarly journals Nd-Fe-B Magnets: The Gradient Change of Microstructures and the Diffusion Principle after Grain Boundary Diffusion Process

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3881 ◽  
Author(s):  
Yaojun Lu ◽  
Shuwei Zhong ◽  
Munan Yang ◽  
Chunming Wang ◽  
Liuyimei Yang ◽  
...  
Keyword(s):  
Surface Layer ◽  
Grain Boundary ◽  
Diffusion Process ◽  
Shell Structure ◽  
Boundary Diffusion ◽  
Diffusion Mechanism ◽  
Temperature Stability ◽  
Grain Boundary Diffusion ◽  
Core Shell ◽  
Core Shell Structure

The diffusion of Tb in sintered Nd-Fe-B magnets by the grain boundary diffusion process can significantly enhance coercivity. However, due to the influence of microstructures at different depths, the coercivity increment and temperature stability gradually decreases with the increase of diffusion depth, and exhibit good corrosion resistance at a sub-surface layer (300–1000 μm). According to the Electron Probe Micro-analyzer (EPMA) test results and the diffusion mechanism, the grain boundary and intragranular diffusion behavior under different Tb concentration gradients were analyzed, and the diffusion was divided into three stages. The first stage is located on the surface of the magnet, which formed a thick core-shell structure and a large number of RE-rich phases. The second stage is located in the sub-surface layer, forming a uniform and continuous RE-rich phase and thin core-shell structure. The third stage is located deeper in the magnet, and the Tb enrichment only existed at the triangular grain boundary.

Electrical Conductivity of Ni-YSZ Anode for SOFCs According to the Ni Powder Size Variations in Core-shell Structure

2015 ◽  
Vol 53 (4) ◽  
pp. 287-293
Author(s):  
Byung-Hyun Choi ◽  
Young Jin Kang ◽  
Sung-Hun Jung ◽  
Yong-Tae An ◽  
Mi-Jung Ji
Keyword(s):  
Electrical Conductivity ◽  
Shell Structure ◽  
Core Shell ◽  
Powder Size ◽  
Ni Powder ◽  
Core Shell Structure

Preparation of Porous Core/Shell Structure Fe$lt;inf$gt;2$lt;/inf$gt;O$lt;inf$gt;3$lt;/inf$gt;/Al Nanothermite Membrane by Template Method

2015 ◽  
Vol 30 (6) ◽  
pp. 610 ◽  
Author(s):  
ZHENG Guo-Qiang ◽  
ZHANG Wen-Chao ◽  
XU Xing ◽  
SHEN Rui-Qi ◽  
DENG Ji-Ping ◽  
...  
Keyword(s):  
Shell Structure ◽  
Template Method ◽  
Core Shell ◽  
Porous Core ◽  
Core Shell Structure

Functional properties of BaTiO3–Ni0.5Zn0.5Fe2O4 magnetoelectric ceramics prepared from powders with core-shell structure

2010 ◽  
Vol 107 (10) ◽  
pp. 104106 ◽  
Author(s):  
L. P. Curecheriu ◽  
M. T. Buscaglia ◽  
V. Buscaglia ◽  
L. Mitoseriu ◽  
P. Postolache ◽  
...  
Keyword(s):  
Functional Properties ◽  
Shell Structure ◽  
Core Shell ◽  
Core Shell Structure

scholarly journals Ternary ZnO/Co3O4/NiO inherited layered core-shell structure from a double template for high performanced supercapacitor

2021 ◽  
Author(s):  
Linli Zhu ◽  
Chen Hao ◽  
Saisai Zhou ◽  
Xiaohong Wang ◽  
Tiantian Zhou ◽  
...  
Keyword(s):  
Shell Structure ◽  
Core Shell ◽  
Core Shell Structure

Composite nanoparticles with titania–poly(N-vinylamide) core–shell structure

2021 ◽  
Vol 31 (1) ◽  
pp. 24-26
Author(s):  
Galina M. Kuz’micheva ◽  
Olesya I. Timaeva ◽  
Irina P. Chikhacheva ◽  
Roman V. Svetogorov ◽  
Ratibor G. Chumakov ◽  
...  
Keyword(s):  
Shell Structure ◽  
Composite Nanoparticles ◽  
Core Shell ◽  
Core Shell Structure

Designing an Interlayer-Widened MoS2-Packed Nitrogen-Rich Carbon Nanotube Core–Shell Structure for Redox-Mediated Quasi-Solid-State Supercapacitors

2021 ◽  
Vol 4 (3) ◽  
pp. 2218-2230
Author(s):  
Sudhakaran Moopri Singer Pandiyarajan ◽  
Ganesh Kumar Veerasubramani ◽  
Roshan Mangal Bhattarai ◽  
Gnanaselvan Gnanasekaran ◽  
Sang Jae Kim ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Solid State ◽  
Shell Structure ◽  
Core Shell ◽  
Core Shell Structure
Sign in / Sign up

Export Citation Format

Share Document