At what temperature do ferrite magnets begin to demagnetize?

Ferrite magnet is a very common permanent magnet, widely used in electronic equipment, electrical appliances, speakers, sensors and other fields, with high corrosion resistance and low cost, and then, ferrite magnets will show different magnetic properties in different temperature environments, especially in high-temperature environments, there will be a gradual demagnetization phenomenon. So, at what temperature will ferrite ceramic magnets start to demagnetize? Please see below.

The accompanying picture shows a radial 4-pole ceramic ferrite magnet rotor.

Compared with other types of magnets (such as neodymium magnets), ferrite magnets at high temperatures in the magnetic properties of the change is more stable, but still subject to the influence of temperature, especially at higher than a certain temperature, ferrite magnets will gradually lose its magnetic properties, a process known as demagnetization.

The demagnetization of magnetic materials is closely related to their Curie temperature, which is the temperature point at which a material loses its spontaneous magnetizing ability, and for ferrite magnets, the Curie temperature is usually between 450°C and 460°C. The Curie temperature is the temperature at which a material loses its spontaneous magnetizing ability.

However, before the temperature reaches the Curie point, ferrite magnets will also gradually lose part of their magnetic properties, especially at temperatures above 200°C, such as 250°C, where the magnetic properties decline more significantly. Therefore, the demagnetization process of ferrite magnets is usually divided into the following stages.

Room temperature to 250 degrees Celsius: The magnetic properties of ferrite magnets do not change much in this temperature range. Even when used in environments with large temperature fluctuations, such as automobile engines and speakers, ferrite magnets maintain their magnetic properties.

250°C to 450°C: This is the temperature range in which ferrite magnets begin to gradually demagnetize, and if the magnets are required to operate for long periods of time in this temperature range, magnetic decay may affect the normal operation of the equipment.

Above 450°C: When the temperature is close to 450°C, the ferrite magnet enters its demagnetization threshold, at which point the magnetism begins to drop sharply.

The above is an introduction to how high a temperature a ferrite begins to demagnetize. If the equipment must work in an extremely high temperature environment, it may be necessary to consider using materials with better high temperature magnetic properties, such as samarium cobalt magnets.

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