High-performance of rare earth magnet along with the market demand

Samarium cobalt magnet and NdFeB magnet both belong to rare earth magnet familiy because of the Sm, Co, Nd, B, Dy, Ga elements in their composition. They are the strongest type of permanent magnets available, producing significantly stronger magnetic fields than other types such as ferrite or alnico magnets, for smco has magnetic energy product about 15 - 30MGOe and sintered neodymium magnet has about 27- 50MGOe.

High-performance of rare earth magnet refers to high magnetic energy products or combination property of the coercivity & magnetic energy products in the conventional sense. Currently, the development degree of the high-property rare earth magnet is influenced by demand of application industry.

The constantly upgraded motors in the new era ask higher coercive force. So higher working temperature and coercive force can ensure the strong ability of anti-demagnetization. For example, due to high transient load, the drive motor in the new energy automobile have critical requirement on the magnet coercive force.

What is the highest working temperature for sintered neodymium magnet?

At moment, no ndfeb magnet can meet 300℃ working temp. Actually, the working temp.of nedfeb magnet depends on its operating environment.Take the drive motor in the new energy automobile for example again, the heat resistance requirement of this drive motor magnet, whether 180℃ or 200℃, rests with the power of the engine. And in actual production, it's necessary to leave some space to keep its temperature stability by choosing higher working temp. magnet than originally working temperature. By this reason, some company will request 220℃ magnet.

Is the high corrosion magnet the future research direction?

To ensure that the electric car can still run after going through more than 20 kilometers cold summer heat, there are many aspects need to be research, such as magnetic property (Max.magnetic energy product, coercivity and remanence), relative physical performance (resistance to corrosion, resistance to oxidation and mechanical property etc.) and reliability working life. So in the premise of guarantee the basic magnetic performance, to prolong magnet's using life is one of the current and future permanent magnet development direction.

Which magnet performance have an impact on motor power and speed?

It's simple structure, small volume, light weight, low loss and high efficiency of rare earth permanent magnet motor. So motor power speed is often about magnetic force. But in the meantime, motor design is very important. Different design with different structure will use different size, quantity,working temp. magnets. You need full consideration here.

What is product homogeneity and the relationship with magnetic declination?

Magnet homogeneity is related to the current stability when the motor output. With bad homogeneity, distribute unevenly magnetic field will cause motor vibration. There are lots of influence factor caused magnetic declination; one is homogeneous materials, the other is uniform magnetization; and some process like magnet perpendicularity is also a factor.