Permanent magnets are the majority of magnetic materials nowadays, they are made of ferromagnetic alloys like rare earth metals and minerals, the main types available in our factory is: Neodymium magnets, SmCo magnets and AlNiCo magnets, after the materials are magnetized, they can create a consistent and indefinite magnetic strength without any external of magnetic field or electrical power.
The characteristics of different permanent magnets are quite different, Neodymium magnets are the strongest magnet commercially available but the least resistant to corrosion, the grades are from N35 to N52 with different magnetic field and different series of coercive force like M, H, SH, UH, EH, AH for higher temperatures etc., SmCo magnets are similar to Neodymium magnet, they can have a high magnetic field up to YXS32 grade, but they are with a higher resistance against high temperature, Neodymium and SmCo magnets are classified as rare earth magnets. AlNiCo magnets are very stable even in very high temperatures, as well as being resistant to corrosion, also they can be produced in very complicate shapes.
Neodymium magnets are made of Neodymium, Iron, and Boron, produced by sintering process. SmCo magnets are made of Samarium and Cobalt, produced by sintering process. AlNiCo magnets are made of Aluminum, Nickel and Cobalt, produced by casting or sintering process.
The corrosion resistance of Neodymium magnets are very poor, a surface coating like NiCuNi will be required, SmCo magnets and AlNiCo magnets are with excellent corrosion resistance, no surface coating is required.
Most permanent magnets (actually all rare earth magnets) are anisotropic, they are oriented in the production process and only magnetized along the oriented direction to achieve the biggest magnetic field. Some AlNiCo magnets are isotropic and can be magnetized along any direction.
Different types of permanent magnets are used in different applications due to their corresponding characteristics, the most common applications are: motors & generators, holding systems, sensors, magnetic bearings, audio equipments, hard disc drives, headphones & loudspeakers, hanging artwork, levitation devices, magnetically coupled pumps, dental instruments, lifting machinery, MRI scanners, medical devices, magnetic separators, packaging closures, POP displays, crafts & model making, commercial signage, reed switches, magnetic tool holders, guitar pick-ups, robotics, security systems, magnetors, drilling equipments, wind turbine equipments, energy recovery systems, rotating machinery, turbo machinery, traveling wave tubes, military radar equipments, pipeline inspection, gyroscopes, halbach arrays.