Entity

Time filter

Source Type


Zhou Q.,CAS Ningbo Institute of Material Technology and Engineering | Li G.,CAS Ningbo Institute of Material Technology and Engineering | Liu Z.,CAS Ningbo Institute of Material Technology and Engineering | Guo S.,CAS Ningbo Institute of Material Technology and Engineering | And 3 more authors.
Journal of Rare Earths | Year: 2016

The electroplating pretreatment of NdFeB magnets was simulated in this study, and the effect of the pickling process on element, matrix morphology and texture was discussed. The results showed that in the ordinary circumstance the acid solution concentration should be below 4 mol/L and the pickling time was within 120 s. However the concentration was lower than 1 mol/L and the time was about 30 s in the ultrasonic environment. The precoating technology sequentially was studied. The results revealed that there were two main reactions of the corrosion and displacement in the precoating process, and these two reactions were more obvious in the grain boundary. The electrochemical analysis illustrated that the corrosion and displacement reactions were affected obviously by the current density and the precoating solution temperature, usually the current density was controlled about 0.3 A/dm2, and the temperature was about 318 K in the precoating process. © 2016 The Chinese Society of Rare Earths. Source


Ren C.,Ningbo Permanent Magnetics Company Ltd | Jin W.,Ningbo Permanent Magnetics Company Ltd | Zhou H.,Ningbo Permanent Magnetics Company Ltd | Li J.,Ningbo Permanent Magnetics Company Ltd | Song X.,Ningbo Permanent Magnetics Company Ltd
Xiyou Jinshu/Chinese Journal of Rare Metals | Year: 2013

By optimizing the alloy compositions, and improving the strip-casting and sintering techniques, 40EH sintered Nd-Fe-B magnets were successfully obtained from common commercially-available raw materials on the mass-production line. SEM analysis showed that the mass-produced high-performance sintered Nd-Fe-B magnets possessed a dense, fine-grained and homogeneous microstructure with an average grain size of about 5~6 μm, and in which there were no abnormally large grains. Typical magnetic properties for 40EH sintered Nd-Fe-B magnets at room temperature were Br=1.288 T, Hcb=996.8 kA·m-1, Hcj=2490 kA·m-1, Hk=2018 kA·m-1, (BH)max=322.0 kJ·m-3; the value of Hcj/79.6 kA·m-1+(BH)max/7.96 kJ·m-3=71.7. And typical magnetic properties for 40EH sintered Nd-Fe-B magnets at 473 K were Br=1.056 T, Hcb=585.8 kA·m-1, Hcj=641.8 kA·m-1, Hk=520.2 kA·m-1, (BH)max=200.9 kJ·m-3; the J-H demagnetization curve had a relatively satisfactory squareness and the B-H demagnetization curve still had a relatively high linearity. In the temperature range of 295~473 K, the temperature coefficients of remanence and intrinsic coercivity were -0.101 and -0.417 (%·K-1), respectively. The irreversible flux loss of the magnet with L/D=0.7 was around 3.8% after being exposed at 493 K for 2 h. The mass-produced 40EH sintered Nd-Fe-B magnets exhibited excellent room temperature magnetic properties and ideal thermal stability. Source


Song X.,Northeastern University China | Song X.,Ningbo Permanent Magnetics Company Ltd | Zhang Y.,Ningbo Permanent Magnetics Company Ltd | Zhang W.,Ningbo Permanent Magnetics Company Ltd | And 3 more authors.
Zhongguo Xitu Xuebao/Journal of the Chinese Rare Earth Society | Year: 2013

: By optimizing the alloy compositions, and improving the strip-casting and sintering techniques, the 45UH sintered Nd-Fe-B magnets were successfully obtained from common commercially-available raw materials on the mass-production line. SEM and XRD analysis showed that the mass-produced high-performance sintered Nd-Fe-B magnets possessed a high alignment degree and a dense and fine-grained and homogeneous microstructure with an average grain size of about 5 μm. The typical magnetic properties for 45UH sintered Nd-Fe-B magnets were Br=1.363 T, Hcb=1060 kA·m-1, Hcj=2140 kA·m-1, Hk=1625 kA·m-1, (BH)max=366.0 kJ·m-3; the value of Hcj/79.6 kA·m-1+(BH)max/7.96 kJ·m-3=72.8. In the temperature range of 295~453 K, the temperature coefficients of remanence and intrinsic coercivity were -0.108%·K-1 and -0.486%·K-1, respectively. The irreversible flux loss of the magnet with L/D=0.7 was around 4.1% after being exposed at 473 K for 2 h. The mass-produced 45UH sintered Nd-Fe-B magnets exhibited excellent room temperature magnetic properties and ideal thermal stability. Source

Discover hidden collaborations