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Introduction to AlNiCo Magnets |
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AlNiCo magnets, are made up of a composite of aluminum, nickel and cobalt with small amounts of other elements, have good temperature stability, good resistance to demagnetization, high residual induction, and relatively high energies. By strength, they are much weaker than NdFeB magnets, SmCo magnets and Ferrite magnets.
Alnico magnets are manufactured by using primarily two processes:
1. Cast alnico magnets that are made by pouring melted alnico into a mold. The solidified material is rough ground and then heat treated and cooled. The material is either anisotropic (treated in a magnetic field) or isotropic (treated outside a magnetic field). After treatment the material is ground to specific tolerances and magnetized.
2. Sintered alnico magnets are made from a powdered mixture of ingredients that are pressed into a die under tons of pressure. They are then sintered in a hydrogen atmosphere and cooled in an anisotropic or isotropic environment.
Alnico magnets are commonly used in applications such as instruments and meters that require very stable temperature properties. Electronic ignition systems, generators, vending machines, hand tools, magnetic reed switches, volt-amp meters and medical instruments are some of the commonly used applications of alnico magnets.
Alnico magnet is one of the first developed permanent magnet materials which is made of aluminum, nickel, cobalt, iron and other trace metal elements alloys. It can be divided into sintered alnico magnet and cast alnico magnet according to different production processes.
Most alnico magnets are in shapes of disc and block; casting process can be used to manufacture magnets with different sizes and shapes, while sintered products limited only to small sizes. The dimensional tolerance of sintered blank is better than the cast one. And the magnetic property of sintered alnico magnet is slightly less than the one of cast alnico magnet, but has better machinability. |
