Ferrite Magnet

Description

Ferrite magnets, sometimes referred to as ceramic because of their production process, are the least expensive class of permanent magnet materials.Ferrite magnets became commercially available in the mid 1950’s and has since found its way into countless applications including arc shaped magnets for motors, magnetic chucks and magnetic tools.

The raw materials of ferrite magnets are mixed in the correct proportions, granulated, and calcined (presintered). After going through several intermediate phases, a hexaferrite phase (BaFe12O19 or SrFe12O19) is achieved. The presintered granulate is ground to a powder. It can then be pressed wet or dry in a magnetic field (anisotropic) or in the absence of a magnetic field (isotropic) and sintered. The nature of the manufacturing process results in ferrite magnets that frequently contains imperfections such as cracks, porosity, chips, etc. Fortunately, these imperfections rarely interfere with a magnet’s performance.

Ferrite magnet is inherently brittle, and it is highly recommended that they NOT be utilized as structural elements in any application. Their thermal stability is the poorest of all the magnetic families, but ferrite magnets may be utilized in environments up to 300 °C (570 °F). The dimensional repeatability of ferrite magnets that as pressed components is difficult to control, consequently, components requiring tight tolerances necessitate secondary grinding operations to assure conformity.