Hard Ferrite Magnet
Hard Ferrite magnets are commonly known as Ceramic magnets due to the process used to produce them. Ferrite magnets are manufactured mainly of strontium or barium ferrites and iron oxide. Hard Ferrite magnets are produced as Isotropic and Anisotropic types. Isotropic type magnets are produced without orientation and can be magnetized in any direction. On the other hand, Anisotropic magnets are exposed to an electromagnetic field during their process to achieve higher magnetic energy and properties. Ferrite magnets have good resistance to demagnetization and with their high Curie temperature they have excellent high working temperatures and most of all they have excellent resistance to corrosion. Ferrite magnets are excellent choices for many applications due to their economical low price and abundance of raw materials and they do not fluctuate much in price. They are the most widely used magnets in a wide range of applications.
The raw material - iron oxide - for hard ferrite magnets is mixed with either strontium or barium and milled down to a fine powdered form. The powder is then mixed with a ceramic binder and magnets are produced through a compression or extrusion molding technique that is followed by a sintering process.
Magnetic and Physical Properties
Hard ferrite magnets are composed of iron and barium or strontium oxides. They conduct magnetic flux well and have a high magnetic permeability. This enables these so-called ceramic magnets to store stronger magnetic fields than iron itself. Hard Ferrite magnets are 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 they may be utilized in environments up to 300°C.
Machining and Dimensions
Ferrite magnets come in a variety of shapes; round, square, rectangular, arc segments, triangle, rings and special shapes. Because of the manufacture equipments constraint, there is a certain limit range of the dimensions and the mechanism accuracy of magnets.
Hall Effect Devices,