Definition - What does Ferrite mean?

Ferrite is a ceramic-like material with magnetic properties, which is used in many types of electronic devices. Ferrite is used in:

  • Permanent magnets
  • Ferrite cores for transformers and toroidal inductors
  • Computer memory elements
  • Solid-state devices

Ferrites are composed of iron oxide and one or more other metals in chemical combination, and their properties include:

  • Hard
  • Brittle
  • Iron-containing
  • Polycrystalline
  • Generally gray or black

Ferrite is also known as ferrate.

Corrosionpedia explains Ferrite

Ferrites are explained as any of a group of nonmetallic, ceramic-like, usually ferromagnetic compounds of ferric oxide with other oxides, especially a compound characterized by extremely high electrical resistivity.

A ferrite is usually described by the formula M(FexOy), where M represents any metal that forms divalent bonds, such as nickel ferrite (NiFe2O4).

Ferrite may refer to:

  • Ferrite (iron) - iron or iron alloys with a body-centered cubic crystal structure
  • Ferrite (magnet) - ferromagnetic ceramic materials used in magnetic applications
  • Ferrite bead - components placed on the end of data cables to reduce interference
  • Calcium aluminoferrite - a mineral found in cements
  • Ferrite core - a structure on which the windings of electric transformers and other wound components are formed

Properties of ferrites include:

  • Significant saturation magnetization
  • High electrical resistivity
  • Low electrical losses
  • Very good chemical stability

Ferrites are often classified as "soft" or "hard" in terms of their magnetic properties:

  • Soft ferrites - used in transformer or electromagnetic cores. They have a low coercivity (manganese-zinc ferrite, nickel-zinc ferrite).
  • Hard ferrites- have a high coercivity. They are cheap, and are widely used in household products such as refrigerator magnets (strontium ferrite, barium ferrite).

Soft ferrite does not retain significant magnetization, whereas hard ferrite magnetization is considered permanent.

Ferrite components are pressed from a powdered precursor and then sintered (fired) in a kiln. The mechanical and electromagnetic properties of the ferrite are heavily affected by the sintering process which is time-temperature-atmosphere dependent.

Ferrite shrinks when sintered. Depending on the specific ferrite, this shrinkage can range from 10% to 17% in each dimension. Maintaining correct dimensional tolerances as well as the prevention of cracking and warpage related to this shrinkage are fundamental concerns of the manufacturing process.

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