Hard Magnetic Ferrite
Ceramic magnets, also called hard ceramic ferrites, are composed of cesium carbonate and iron oxide, and are widely used in motors, speakers, toys, etc. because of their good anti-demagnetization and low cost.
Ferrite magnets are manufactured by sintering and injection molding processes. Although the molds used for injection molding are very expensive, they can be used for processing products with complex shapes and tight tolerances.
Although hard magnetic ferrite magnets have poor thermal stability, they can be used in environments up to 300 degrees Celsius. Because they are hard and brittle, they can only be cut and ground with a diamond wheel. The ferrite has very good rust resistance, so there is no need to treat the surface.
After the raw materials are proportioned, they are granulated, and then calcined (pre-sintered) and then after several transition stages, a barium ferrite phase (BaFe12O19 or SrFe12O19) is gained.
After the pre-sintered particles are ground into a powder, they are wet or dry pressed into a magnetic field (non-isotropy, anisotropy) or isotropic (isotropic) and sintered. Ceramic materials for the hard magnetic ferrite system has the mechanical hardness and brittleness of ceramic and are usually ground by a diamond circular saw blade.
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