It is easy to find many rare earth permanent magnets in our daily life. This is a very common feature in household appliances. These magnets are permanent magnets, which sounds fancy to many people. But do you know how it is different from other types of magnets? Then let's learn the history of rare earth permanent magnets together.SourceRare earth magnet-https://www.rare-earthmagnet.com/rare-earth-permanent-magnets/
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I. History of rare-earth permanent magnets.SourceRare earth magnet-https://www.rare-earthmagnet.com/rare-earth-permanent-magnets/
In the last century, scientists at the U.S. Air Force Materials Laboratory developed rare-earth magnets. They found an alloy with the greatest magnetic anisotropy. They named this alloy "rare-earth magnets". The name suggests that these materials are rare, but in fact they are actually as abundant as iron or gold. Moreover, the main source of raw materials is China. Because China is rich in rare earth resources.SourceRare earth magnet-https://www.rare-earthmagnet.com/rare-earth-permanent-magnets/
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Second, how to produce rare earth permanent magnets.SourceRare earth magnet-https://www.rare-earthmagnet.com/rare-earth-permanent-magnets/
First the raw material is sent to the manufacturer and it will be ground into powder. Then it will be mixed with other materials to make magnets. And the grade and magnetic properties it carries will be different depending on the content of the raw material and other materials. The powder will be pressed into a shape (usually rectangular, square or round). After the particles are aligned, the material is sintered to lock everything into place. In the future, this material will be further processed and cut into smaller pieces. After confirming the final shape, the magnet will need to be cut. Surface treatments and plating are also typically required, and they protect the magnet from corrosion. Finally, the magnet will be magnetized. Finally it becomes the powerful magnet we use.SourceRare earth magnet-https://www.rare-earthmagnet.com/rare-earth-permanent-magnets/
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Third, how to make rare permanent magnet quality.SourceRare earth magnet-https://www.rare-earthmagnet.com/rare-earth-permanent-magnets/
Because rare earth permanent magnets are made of different powders and different alloys. Therefore they have different quality and strength from other magnets. In this business, BHMax is used to measure the magnetic field. For example, ferrite magnets (high strength in magnets) have a BHMax of 3.5 and the strongest rare earth magnets have a strength of 40. while ferrite magnets will be lower.SourceRare earth magnet-https://www.rare-earthmagnet.com/rare-earth-permanent-magnets/
If the temperature is too high, the magnet will demagnetize. We call the temperature as the maximum working temperature value. And different materials of magnets have different operating temperatures. This means that rare earth magnets can withstand higher temperatures before demagnetization.SourceRare earth magnet-https://www.rare-earthmagnet.com/rare-earth-permanent-magnets/
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A rare earth magnet is a magnet that includes rare earth metals. There are 17 members of rare earth metal family, including La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y, Sc. The rare earth metals Pr, Nd, Dy are used as raw materials for NdFeB, while Sm is used as raw material for sa cobalt.SourceRare earth magnet-https://www.rare-earthmagnet.com/rare-earth-permanent-magnets/
Rare earth metals are very expensive because it is a rare resource. It also causes environmental damage in the mining process. Therefore, some countries like USA, Russia and Australia stop mining and buy cheap rare earth materials or products from China. The fluctuation in the price of rare earth metals is an important factor in the increase in the price of rare earth magnets.SourceRare earth magnet-https://www.rare-earthmagnet.com/rare-earth-permanent-magnets/
The chemistry of rare earth magnets is based on the intermetallic compound Nd2Fe14B. magnets have a high magnetic energy product and coercivity. At the same time, the advantage of high energy density makes rare earth permanent magnets widely used in modern industry and electronics, thus making it possible to miniaturize, lighten and thin equipment.SourceRare earth magnet-https://www.rare-earthmagnet.com/rare-earth-permanent-magnets/
The main rare earth magnets are NdFeB and SmCo.SourceRare earth magnet-https://www.rare-earthmagnet.com/rare-earth-permanent-magnets/
1.NdFeB magnets
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NdFeB sintered magnets are the most powerful and cost effective magnets in the world. It is widely used in computers, electric motors, wind turbines, electric vehicles, instrumentation, magnetic drive bearings, high-fidelity speakers, nuclear magnetic resonance (NMR) imaging and aerospace navigators. It also plays an important role in new technologies such as magnetic levitation trains. Cheap Pr-Nd metal replaces pure Nd to improve its oxidation resistance and mechanical properties. Dy is an additive used in high-grade Nd-Fe-B magnets. Adding only 2-3% of Dy can increase the coercivity of magnets. As the demand for magnets increases for high-end products, the demand for Dy is also increasing.SourceRare earth magnet-https://www.rare-earthmagnet.com/rare-earth-permanent-magnets/
2. Samarium Cobalt Magnets
Samarium Cobalt is the first rare earth magnet in the industry, including SmCo5 and Sm2Co17. but currently Sm2Co17 is the preferred material. The purity of oxide oxide used in samarium cobalt magnets is not very high. For cost consideration, 95% oxide sa products are sufficient.SourceRare earth magnet-https://www.rare-earthmagnet.com/rare-earth-permanent-magnets/
The main applications of rare earth magnets.SourceRare earth magnet-https://www.rare-earthmagnet.com/rare-earth-permanent-magnets/
Rare earths are mainly used in micro motors, permanent magnet instruments, electronics industry, automotive industry, smart home, nuclear magnetic resonance equipment, sensors, audio equipment, magnetic levitation systems, magnetic transmission mechanisms and magnetic therapy equipment. It is widely used in computers, magnetic machinery, automatic control, microwave communication, aerospace, medical equipment and other fields. Usage.SourceRare earth magnet-https://www.rare-earthmagnet.com/rare-earth-permanent-magnets/
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Both ferrite magnets and samarium cobalt magnets are rare earth permanent magnets, which are more resistant to corrosion. Neodymium magnets are also rare earth magnets, but are more brittle. And about manufacturing, NdFeB magnets are very difficult to produce. In short, rare earth magnets are not magic products. So what we should do is to know more about them.SourceRare earth magnet-https://www.rare-earthmagnet.com/rare-earth-permanent-magnets/
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