Monthly Archives: April 2019

Definition of permanent magnet material

Common permanent magnet materials are AlNiCo, ferrite permanent magnet materials and rare earth permanent magnet materials. Alnico-cobalt alloys have been developed from Al-Ni-Fe alloys. At present, the types of Al-N-cobalt alloys that can be manufactured in China are mainly LNG34, LNG52, LNGJ32, LNGJ56 and so on. Since the main characteristic of AlNiCo is high Br (residual magnetic induction) and low coercive permanent magnet materials, the relative magnetic permeability is above 3, so in the specific application, the magnetic pole must be a growth cylinder or a long rod. to minimize the effect of effect.

The AlNiCo magnet has a low coercive force. Therefore, any iron device should be strictly prohibited from contacting the AlNiCo permanent magnet material during use to avoid local demagnetization of the permanent magnet and distortion of the magnetic flux distribution in the magnetic circuit. The advantage of the AlNiCo magnet is that the temperature coefficient is small, and the deterioration of the permanent magnet characteristics due to temperature changes is small, but the material is hard and brittle, and processing is difficult. The main applications of AlNiCo are in electronic ignition systems, watt-hour meters, voltammeters, medical instruments, industrial motors, magnetic reed switches, generators, hand tools, vending machines, etc.

Ferrite permanent magnet material is one of the most widely used permanent magnet materials, and its main component is MoFe2O3. It has the advantages of large coercive force, light weight, abundant raw material source, low price, oxidation resistance, corrosion resistance, large anisotropy constant of magnetic crystal, and approximate demagnetization curve as straight line. The disadvantage is that the residual magnetism is low, the temperature coefficient is large, and it is brittle. The coercive force of the ferrite permanent magnet material is between the AlNiCo material and the rare earth cobalt permanent magnet material. Because of its low remanence, it is generally suitable for design into a flat shape. Due to its low cost, ferrite magnetic materials have a wide range of applications, from motors and speakers to toys and handicrafts, making them the most widely used permanent magnet materials. The rare earth permanent magnet material has the advantages of high coercive force, large maximum magnetic energy product, and reversible magnetic permeability equal to one. Therefore, its magnetic properties far exceed that of other magnetic materials such as ferrite and aluminum nickel cobalt.

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