Magnets are very useful in our lives. For example, they can be used on speakers, motors, and electronic instruments, etc. There are many types of magnets available on the market today. Depending on their material, magnets can be divided into ferrite magnets, neodymium magnets, SmCo magnets, and AlNiCo magnets. In our last article, we’ve introduced what is a ferrite magnet. So in today’s article, let’s figure out what are SmCo magnets.
Samarium cobalt magnet is a rare earth magnet. It is made from samarium, cobalt, and other metal rare earth materials through mixing, smelting into an alloy, and then crushed, pressed, and sintered.
SmCo magnets have a high magnetic energy product and extremely low-temperature coefficient. Their maximum operating temperature can reach 350℃. When the working temperature is above 180℃, their maximum magnetic energy product (BHmax), coercivity, temperature stability, and chemical stability all exceed those of the NdFeB permanent magnet materials.
Thanks to SmCo magnets’ strong corrosion and oxidation resistance, they are widely used in aerospace, defense, and military industry, microwave devices, communications, medical equipment, instruments, meters, various magnetic transmission devices, sensors, magnetic processors, motors, magnetic cranes, etc.
1. Maximum magnetic energy product (Bhmax) 160-150 KJ/m3 (15-35 MGoe)
2. Maximum working temperature (Temp. Tw) 250-350
3. Intrinsic coercive force (HcJ) KA/m
4. Magnetic coercivity-Hcb 650-870 (KA/m), 4-12 (Koe)
5. Remanence-Br 8-12 (KGs), 0.8-1.2 (T)
6. Reversible temperature coefficient of remanence (Br) -0.04— -0.01
1. Very good coercivity.
2. Good temperature stability (maximum service temperature is 250 to 550℃; Curie temperature is from 700 to 800℃).
1. Expensive and susceptible to price fluctuations.
2. SmCo magnets can easily shatter. You must wear goggles when handling them.
In 2012, Toshiba Corporation of Japan developed a high iron concentration SmCo magnet for engines. This magnet is completely free of rare earth element dysprosium, but its magnetic force is stronger than the heat-resistant neodymium magnets widely used now.
The newly developed high iron concentration samarium cobalt magnet uses heat treatment technology independently developed by Toshiba. This makes the samarium cobalt magnet, which is originally inferior to the neodymium magnets in terms of magnetic force, possesses a stronger magnetic force than the heat-resistant neodymium magnet in an environment above 100 degrees Celsius.
In order to increase the magnetic force, the researchers increased the weight ratio of iron in the magnet from the original 15% to 20% – 25%, and adjusted the temperature, time, pressure during sintering to achieve the best state, thereby reducing the effect of oxides and other factors that hinder the increase of magnetic force. At the end of 2012, this new magnet was already on the market.
Thank you for reading our article and we hope it can help you know what are SmCo magnets well. If you want to know more about SmCo magnets, we would like to recommend you to visit Stanford Magnets for more information.
Stanford Magnets is a leading magnet supplier across the world, who has been involved in R&D, manufacturing, and sales of SmCo magnets since the 1990s. It provides customers with high-quality rare earth permanent magnetic products such as neodymium magnets, SmCo magnets, and other non-rare earth permanent magnets at a very competitive price.