Alnico
Characteristics
1. High energies and relatively low coercive force
2. High magnetic flux density and resistance to demagnetization from vibration and shock
3. Both isotropic and anisotropic are available.
4. Excellent resistance to high temperature alnico has the lowest temperature coefficient of any commercial magnet material, providing for excellent stability over a wide temperature range. A properly designed circuit using alnico magnets will have a stable flux output during temperature fluctuations. The maximum working temperature for alinico is 510c (950f).
Common applications
Magnetos, separators, mri, sensors, holding magnets, security system, relays, volt-amp meters, industrial motors
Samarium-Cobalt (SmCo) rare earth permanent magnets
SmCo magnets are manufactured with sintering or compression bonding. They are anisotropic and can only be magnetized in the direction of orientation. In general, magnetizing fields of approximately 30KOe to 45KOe are required to saturate SmCo magnets. There are two types for alloy materials, 1:5 and 2:17.
Characteristics:
1.High magnetic properties The intrinsic coercive force could reach up to 22KOe.
2.Low temperature coefficient For some materials, ¦Á could reach low to -0.01% of Br/¡ãC.
3.High working temperature SmCo The maximum recommended working temperature is 250¡ãC(480¡ãF) for SmCo 1:5 and 350¡ãC(660¡ãF) for SmCo 2:17. The Curie Temperature could reach high to 750¡ãC(1390¡ãF) for SmCo 1:5 and 850¡ãC(1560¡ãF) for SmCo 2:17.
4.High resistance to corrosion No coating is needed for surface protection. .
Common applications
High performance motors, Magnetic couplings, Magnetic separators, Aerospace defense, Magnistors, Instruments and meters
Neodymium-Iron-Boron (NdFeB) rare earth permanent magnets
Known as the Third Generation of Rare Earth magnets, Neodymium-Iron-Boron (NdFeB) magnets are the most powerful and advanced commercial permanent today. Since made from Neodymium, one of the most plentiful rare earth elements, and inexpensive iron, NdFeB magnets offer the best value in cost and performance. NdFeB magnets are available in both sintered and bonded forms. Sintered NdFeB offers the highest magnetic properties (33MGOs to 51MGOe) while boned NdFeB offers lower energy. Although boned magnets do not possess magnetic properties as advanced as those of sintered magnets, they can be made in shapes and sizes that are difficult for sintering to achieve.
Characteristics:
1. Moderate temperature stability The working stability is under 80¡ãC (180¡ãF) for low Hcj NdFeB magnets and above 200¡ãC (400¡ãF) for high Hcj NdFeB magnets.
2. Excellent energy The highest energy product could reach up to 51MGOe.
3. Extremely resistance to demagnetization with Hci The intrinsic coercive force is over 30KOe.
4. Surface treatment needed Because NdFeB is easy to oxidize and corrode, coating or plating must be applied to the surface to protect magnets from oxidization and corrosion.
Common applications
DC and servo motors, Linear actuators, Magnetic separators, Speakers, Microphone assemblies, Sensors, VCM (voice coil motor), MRI
