News

News

NETZSCH: Process Technology for Rare Earth Alloys

Date: 2018-12-24
Views: 137

NETZSCH: Process Technology for Rare Earth Alloys

   Booth Number:C500


The era of electromobility presents new challenges which must be mastered by both man and materials. Today, neodymium-iron-boron-magnets are used in areas in which strong magnetic fields at low volumes and low weights are necessary. These so-called rare earth magnets guarantee the resource conservation of raw materials, weight reduction of the drives and longer service lives required of permanent magnets. However, they are more complicated to manufacture than conventional magnets. A decisive factor for the quality and properties of permanent magnets is a raw material with a narrow particle size distribution with the lowest possible fraction of finest- (< 2 µm) and coarsest particles (> 8 µm).


NETZSCH: Process Technology for Rare Earth Alloys

The NETZSCH company offers innovative solutions to this application problem with a patent pending grinding process with downstream classifying of rare earth powders. The design of this process led to the development of jet mills and ultra-fine classifiers with which sensitive Nd-Fe-B-compounds or other rare earth alloys can be ground reliably to fine powders under inert gas operation giving a narrow particle size distribution and defined upper particle size limit with reproducible results.


With NETZSCH m-Jet, a combination of a spiral jet mill with a dynamic air classifier, highest reproducible finenesses independent of the load in the gas jets are obtained. A decisive advantage of the m-Jet compared to fluidized bed jet mills or target mills is the possibility of the automatic rejection of components which are difficult to grind. This requires only a few seconds and takes place during operation of the m-Jet. The overpressure in the mill ensures that components which are difficult to grind are transported into the filter. In this way, there is absolutely no problem caused by contamination of the product-conveying piping with coarse product particles and/or these problematic components. Furthermore, due to the differences in design, the product content during the grinding phase of an m-Jet is 20 to 25 times lower than that of a fluidized bed jet mill with the same amount of grinding gas. At the same time, this results in an extremely low product loss during product change due to the smaller volume of the grinding chamber. In addition to this, practically no fluctuations in throughput capacity and especially in the particle size distribution occur during start and stop of the plant. Furthermore, a selective grinding of individual alloy components does not take place.


The dynamic air classifier integrated in the m-Jet ensures a clearly defined maximum particle size of the ground product. In a subsequent step, undesirable finest particles are separated out by classifying the ground material with a NETZSCH High-efficiency Fine Classifier m-Class to obtain a powder with a defined, narrow particle size distribution. Compared to a ground product with a d10 value of 1.54 µm, the d10 value of the subsequently classified product is 2.03 µm and the proportion of ultra-fine particles < 1 µm is almost 0.0 %. The d90/d10 value also improves significantly from 3.6 to 2.6 (each with d50 = 3.0 µm) after additional classifying.


The higher grade of the raw materials produced using the mentioned process is reflected in the quality of the magnets manufactured with them. Compared to magnets made of ground powder only, rare earth magnets made of classified powder have a higher coercive field strength and significantly improved knee-field strength. Therefore, they are more suitable to be used to meet future challenges, which will be characterized by a progressively increasing miniaturization at constant throughput.

News / Recommended news More
2019 - 09 - 11
Engineers at the University of California, San Diego have developed a process for welding ceramics that could have wide-ranging implications for the hardiness and construction of electronics.According to a paper published in Science on August 23rd,, UC-San Diego researchers have used a sub-50-watt, rapidly-pulsing laser to melt and fuse ceramics, upending traditional ceramics welding met...
2019 - 09 - 06
Researchers have found a way to use 3D printing to stretch and flatten twisted polymers so that they conduct electricity better. The researchers, led by chemical and biomolecular engineers from the University of Illinois at Urbana-Champaign, report their findings.Conjugated polymers are formed from the union of electron-rich molecules along a backbone of alternating single and double chemical bond...
2019 - 08 - 28
We live in a ceramic world. Ceramics are everywhere even in the world of engineering. The most important and general property of ceramics is that they are refractory. What does this mean? They are “rough-and-tumble” materials that will take large amounts of abuse in a wide range of situations. Ceramic tiles are used for space shuttles. The composite is able to withstand tremendous temperature...
2019 - 08 - 21
Samples of the new ceramic aerogel, which is incredibly lightweight and can withstand intense heat fluctuations(Credit: Oszie Tarula/UCLA)Ceramic aerogels have been protecting industrial equipment and space-bound scientific instruments for decades, thanks to their incredible lightness and ability to withstand intense heat. The problem is they can be pretty brittle. Now, a team led by research...
Share:
Uniris Exhibition Shanghai Co., Ltd.
Shanghai Branch
Tel: 4000 778 909 
E-mail:irisexpo@163.com

Guangzhou Branch
Tel: 020-8327 6389
E-mail:iacechina@unifair.com

IACE CHINA Official Website
犀牛云提供企业云服务
犀牛云提供云计算服务
Scan