Current Applications of Ferrite Magnets
These are some of the reasons why many companies buy ferrite magnets instead of more expensive alnico magnets and very high-priced rare earth magnets. Find out all the ferrite magnets applications.
Ferrite magnets were first introduced in 1952. In their simplest form, they consist of iron oxide mixed with barium carbonate or strontium carbonate. The components are calcined (heated above 1000 °C in the absence of air), cooled, milled to a fine powder, compacted into a die, and sintered at high temperature. A strong external magnetic field is used to align the magnetic particles. The resultant permanent magnet is extremely hard and strong but rather brittle. These magnets are known as ceramic magnets thanks to the production process.
Magnets made from ferrite have a maximum flux density of around 4,000 gauss, similar to that of alnico. This is much lower than rare earth magnets that range from 15,000 to 50,000 gauss. On the other hand, they are extremely reasonable in price.
Points to Consider When You Buy Ferrite MagnetsThanks to their low cost, ferrite magnets are used in many applications, particularly when there's no requirement for a high flux density or small size. When evaluating a decision to buy strong magnets, factors to consider include the type of magnet, its shape and physical properties.
Ferrite magnets are either soft or hard. This term does not refer to the hardness of the material, but to its magnetic characteristics. A soft magnet is one that has low coercivity, which makes it useful for alternating current applications such as high frequency transformers and switched power supplies. On the other hand, hard ferrite magnets possess high magnetic permeability and a strong residual magnetic field. Hard ferrite magnets are used in loudspeaker coils, DC motors and similar applications.
Because ferrites are sintered, they are supplied in many shapes including blocks, discs and rings. Ferrite magnets are very hard and difficult to machine, so it's best to specify the exact size before you buy strong magnets. Ceramic magnets can be encased in a pot magnets to concentrate the magnetic force in one direction.
A notable characteristic of ferrite magnets is their high temperature stability. Most can be used up to 250 °C and exhibit a positive temperature characteristic, unlike other magnets. Conversely, they are less suitable for use at temperatures below zero and may permanently lose their magnetism. Ceramic magnets are good electrical insulators. They are corrosion-resistant and do not require additional corrosion protection for outdoor use, in liquids or chemically contaminated locations. Additionally, ceramic magnets are safe to handle because of the lower magnetic flux density. Ceramic magnets are strong, especially when encased in plastic or steel.
Ferrite magnets are used in many applications, including:
• Permanent magnet DC motors
• AC commutator motors
• Magnetic catches
• Hard drives
• ABS systems
• Magnetic shock absorbers
• Microphones and acoustic detectors
• Plate magnets
• Lifting magnets
• Magnetic clamps
• Magnetic brakes
These are some of the reasons why many companies buy ferrite magnets instead of more expensive alnico magnets and very high-priced rare earth magnets. Thanks to their excellent physical properties, they are commonly found in many situations where extremely high magnetic field densities are not required.
To find out more about ferrite magnets, contact us at our UK office.