Common knowledge about the high temperature resistance of magnets

Many companies who buy magnets have a vague idea of the temperature at which the magnets can be used. Of course, this issue cannot be explained in a few words. It involves quantum mechanics, thermodynamics, solid mechanics and other aspects. If they are shown the company’s table, they still feel unintuitive. I refer to a lot of information from home and abroad. Maybe because this issue is too involved for me to fully understand, but I still want to talk about my personal humble opinion.

As magnet factories like to say that their magnets will never demagnetize, but everything in the world has a movement side, non-demagnetizing permanent magnets do not exist, there are many reasons for demagnetization, but the main internal reason is the internal molecular thermal movement of the magnet, the thermal movement can change the direction of the magnetic poles, or even let the magnetic disintegration, the magnet is not magnetic at all. The temperature of the magnetic disintegration is the internal point, the internal point is generally expressed by TC, the magnet we sell is about 450℃ for ferrite, 860℃ for Alnico, 320℃-380℃ for NdFeB and 450℃-840℃ for Barium Cobalt. The height of the internal point is related to the crystal structure formed by the magnet sintering, with impurities, cooling environment, alloy composition ratio, sintering specific process (composition melting ingot, powder pressure type, sintering tempering magnetic detection, grinding processing, pin cutting processing, plating finished products).

The indoor temperature of common magnets is about 450℃, NdFeB magnets 320-380℃, Alnico 860-900℃.

Operating temperature: 80~100℃ for ferrite magnets, up to 350℃ for high temperature resistant models;
Alnico magnets 450~900℃.

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