The Importance of Rare Earth Magnets to the Global Industry
The Importance of Rare Earth Magnets to the Global Industry
Rare earth magnets refer to strong permanent magnets composed of rare earth element alloys. The most common rare earth magnets are neodymium magnets and SmCo magnets. The two types of magnets contain neodymium and samarium in rare earth elements, respectively. Among permanent magnets, rare earth magnets can generate the largest magnetic field, which is much larger than that of Alnico magnets or ferrite magnets. Therefore, they play an important role in the industry. In this article, let’s take a closer look at the uses and importance of rare earth magnets to the global industry.
Before diving into our article, let’s figure out some common sense about rare earth magnets.
Reasons for the Magnetism of Rare Earth Magnets
Rare earth elements are ferromagnetic metals. Like iron, they can be magnetized and become permanent magnets, but their Curie temperature is lower than room temperature. Therefore, pure rare earth elements are only magnetic at low temperatures. However, if rare earth elements form compounds with transition metals such as iron, cobalt, and nickel, the Curie temperature will be higher than room temperature, and rare earth magnets are made of such compounds.
The reason why rare earth magnets have higher magnetic properties than other magnets is that their crystal structure has high magnetic anisotropy, that is, metal crystals can be easily magnetized in a specific direction, but it is difficult to magnetize in other directions.
The reason why rare earth elements can maintain a high magnetic moment in solids is that the electrons of the f orbital are not filled, and up to 7 unpaired electrons can spin in the same direction. The electrons in these atomic orbitals have been highly localized, so they can maintain their magnetic moments and produce a function similar to a paramagnetic center.
Because electrons in other orbitals overlap with neighboring orbitals, it is difficult to maintain their magnetic moments. For example, electrons participating in covalent bonds form electron pairs, and the total spin is zero. The high magnetic moment and high magnetic anisotropy at the atomic level result in the strong magnetism of rare earth magnets.
Magnetic Properties of Rare Earth Magnets
Important properties of magnets include:
1. Remanence (Br): used to measure the strength of the magnetic field;
2. Coercivity (Hci): the ability of the material to resist demagnetization;
3. Magnetic energy product (BHmax): the density of magnetic energy;
4. Curie temperature (Tc): the temperature at which the magnet loses its magnetism;
Rare earth magnets have high remanence, coercive force and magnetic energy products are much higher than other magnets, but the Curie temperature of neodymium magnets is lower than other magnets.
The Uses and Importance of Rare Earth Magnets to the Global Industry
Since the price of rare earth magnets has gradually decreased since 1990, they can replace AlNiCo magnets and ferrite magnets in many technological products that require magnets.
Common uses of rare earth magnets include:
1. Computer Disc
2. Wind Turbines
3. Speakers and Headphones
4. Brakes for Fishing Reels
5. Permanent Magnet Motor in Cordless Drill
6. High-Performance AC Servo Motor
7. Traction Motors for Hybrid or Electric Vehicles
8. Flashlight that Can Generate Electricity after Shaking
9. Linear Motors Used in Maglev Trains
10. Electric Bearing
11. NdFeB Magnet Toy
12. Pickups for Electric Guitars
Conclusion
Thank you for reading our article and we hope it can help you to have a better understanding of the uses and importance of rare earth magnets to the global industry. If you want to learn more about magnets, we would like to advise you to visit Stanford Magnets for more information.
As a leading magnet supplier across the world, Stanford Magnets has been involved in R&D, manufacturing, and sales of magnets since the 1990s. It provides customers with high-quality permanent magnets like SmCo magnets, neodymium magnets, AlNiCo magnets, and ferrite magnets (ceramic magnets) at a very competitive price.