Research and Application of Sintered NdFeB

- Nov 10, 2017 -

China's abundant rare earth resources, low labor costs and a wide range of applications, to the development of magnet neodymium materials provides a very convenient conditions. According to Chen Lixin 2006 research report, China's neodynium magnets material production accounts for about 70% of the world, but the output value is only about 40% of the world, mainly due to the lower performance of our products, the price Not high, but also with the vicious competition in our industry related. Therefore, efforts should be made to increase technological innovation and technological transformation, to strengthen enterprise management, to continuously improve product quality and product quality so as to make our country a true magnetic material center.

  1. Neodymium rare earth magnet materials research status quo

Neodymium magnet material since the beginning of the invention in 1983, with its high theoretical energy product to attract worldwide attention, although the preparation of the material has been more mature technology, industrial production has also achieved more than 20 years, but there are Some key technologies need to be exceeded, and there is still a certain gap between our production technology and that of other countries. Prior to 2003, the main goal of the study on rare earth magnets was to increase their energy product, whereas after 2003 the main focus was on increasing the coercivity and operating temperature of the material. So far, the researchers conducted detailed and in-depth research on all aspects of the preparation of strong magnets materials and achieved good results.

1.1. Recipe and add element research

Sintered Nd-Fe-B permanent magnet theoretical energy product can reach 512kJ / m3. In the formula study, in order to improve the magnetic energy product of the material, it should reduce its rare earth content and increase the iron content. However, with the decrease of rare earth content, a series of problems will be brought to the sintered NdFeB permanent magnet materials, the most serious of which is the oxidation of the powder and finally the magnetic energy product of the material. Currently, sintered NdFeB permanent magnets Material magnetic energy product up to 400kJ / m3 or more, has basically solved this problem. In addition, in order to improve the performance of some aspects of the material, we have studied the introduction of some elements conducive to the improvement of the material properties. For example, Dy, Nb, Cu, Al, Ga and the like can be added to improve the coercive force of the material; Of the temperature stability, you can add Co, Dy, Si, Sn, Nb and so on.

1.2. Preparation of the research

Super strong magnets materials for the traditional preparation process: ingredients - smelting - milling - forming - sintering. Because of each link are closely related with the material properties, so the process of in-depth study and grasp is extremely important.


2. Super strong neodymium magnets materials application progress

Rare earth neodymium magnets materials in daily necessities have a more extensive application, such as general electric tools, watches, cameras, tape recorders, VCD and so on. Because of the good performance of the material and cost-effective, conducive to the realization of the miniaturization of electronic products and ultra-thin, it is now a lot of home appliances have applications; the same time, the material can make the overall device performance is greatly improved, which is One of the important reasons for its flourishing production.

large neodymium magnets are used in computer disk, optical disk drive and printer driver head, and the transfer of these industries to China in recent years has made the computer become the main application field of ndfeb magnets materials in China.

With the continuous improvement of medical care, the demand for high-end medical devices in China continues to grow. Almost every hospital of a small size has a magnetic resonance imager. However, this device uses a large amount of high-performance magnets rare earth material.

Rare earth permanent magnet motor because there is no excitation coil and core without loss, no heat, can reduce energy consumption. Use of the efficient motor can save 15% to 20%, reduce the motor quality of more than 20%. However, the current rare earth permanent magnet motor output is not large, only about 0.5% of the total output of various types of motors. If the rare earth permanent magnet motor can be further replaced by the traditional series of motors, the demand for sintered NdFeB permanent magnet materials will be even greater.

In the automotive industry, sintered NdFeB permanent magnet materials(small scale industry rare earth magnets) have been used in automotive ignition coils, electric power steering, a variety of control motors and car audio. As people's living standards improve, the automotive industry will further develop, so the industry for high-performance sintered NdFeB permanent magnet materials will have greater demand.

Previously, the overall performance of strongest rare earth magnet was low, so they were widely used in middle and low-grade devices such as magnetizer, wax remover, general motors, sensors, magnetic coupling, magnetic separator, However, in recent years, the integrated magnetic properties of sintered NdFeB have been improved, and its applications have been extended to VCM, MRI and micro-motor.

In addition, ultra-high coercivity sintered NdFeB permanent magnet materials are mainly used in high operating temperatures such as electric vehicles, electric bicycles and some of the higher ambient temperature motor. Permanent magnets made of sintered NdFeB magnetic materials are also widely used in automobiles, bank depositories and safes. Magnetized water for industrial and civil use, to prevent scale production and eliminate scale, improve water quality, while extending equipment life and ensure operational safety.

3. Domestic and foreign neodymium magnets strong magnets materials comparison

At present, China's powerful magnets materials are mainly used in ordinary audio, magnetizer and wax remover, motor and sensor, and are expected to further increase their application in fields such as motor and voice coil motor [25].

It is understood that the main applications of neodymium iron boron materials in the Western countries are voice coil motors, permanent magnet motors, nuclear magnetic resonance apparatus, high-end audio equipment, etc., our country is still relatively few applications in these areas. Although the application of super magnet in our country in the field of audio-video electronics is in a dominant position, but this area is only the material used in the low-end market.

Our country in the high-end computers and computer peripherals such as the competitiveness of the market is still weak, but the most competitive in this regard is the invention and production of sintered NdFeB Japan, followed by the United States. The United States has great strength in the application of magnetic resonance imaging equipment, but its strength in the fields of electromechanical, audio-visual electronics and communications electronics is weaker, which is related to its lack of raw materials, high human resource costs and the large number of overseas production enterprises relocating . Therefore, our country should seize this opportunity to intensify the research and development of sintered NdFeB permanent magnetic materials.

4. Outlook

At present, China's neodymium iron boron magnets material output has ranked first in the world, is a real big producer. But the domestic NdFeB permanent magnet materials in product performance compared with foreign countries there is a big gap, mainly for the thermal stability of the material, oxidation resistance is not completely solved; product magnetic properties are not stable, decentralized ; Permanent magnet processing, magnetization technology is still not off, which are in urgent need of further exploration. We should make full use of China's rare earth resources, human resources advantages, increase technology research and development efforts.

With the continuous improvement of science and technology, Sinterd Neodymium Magnets materials are also constantly expanding the application areas, for manufacturers, on the one hand should strive to make the product's performance higher and more stable; on the other hand also dedication To open up a larger application market. This not only requires manufacturers to provide good products, but also provide the appropriate technical support to better serve the application of sintered NdFeB permanent magnet materials business, thereby promoting the sustainable development of NdFeB and related industries.

Article from NdFeB Industry Network

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