Ferrite Permanent Magnet Blocks with North Pole Mark

What are ferrite permanent magnets?How to make ferrite magnets?

Permanent ferrite magnet is more commonly referred to as Ceramic Magnet. They are obtained from iron oxides and from strontium or barium carbonate: these raw materials are generous on Earth, so availability of ferrite is rather high.

The raw materials are mixed together, granulated and thermally treated to get finally hexaferrite phase (SrFe12O19 or BaFe12O19). This granulate is then ground to a powder.Pressing can be performed under magnetic field (to maximize anisotropy of the magnet) or not (isotropic ferrite magnet) and can be wet or dry.

Features & Benefits

Due to their ceramic nature, ferrite magnets are very hard and brittle. Special machining techniques must be utilized for these magnets. Ceramic or ferrite magnets come in discs, cylinders, rings, blocks and arcs and are charcoal grey.

Ferrite permanent magnets are a low cost solution to an endless list of magnetic applications.As important parts of magnetic materials, ferrite (ceramic) magnets play an important role in electrical, electronic information, car, motorcycle industries etc. They are also widely used in medical treatment, mining and metallurgy, industrial automation, oil energy and civil industries.

Are surface treatments required for a Ceramic Ferrite Magnet?

Both Isotropic Ferrite Magnets and anisotropic ferrite magnets do not need to be protected for surface rust. A thin film of magnet powder on the surface is common.

Slightly pinched edges, stains, fine cracks, are specific to the material and production process and do not affect in any way the performance of the magnet.

What shapes are available for ferrite permanent magnets? 

In principle all shapes can be produced by mold pressing: rod magnet,bar magnet, Block Ferrite Magnet, Ferrite Ring Magnet and other shapes. Sharpedges and corners have to be avoided as the high brittleness level of the material can cause cracks and fractures.

Drill holes and grooves can only be applied in the direction of pressing, because the preferred direction is usually parallel to it.

Indirect shaping is also possible.  This is usually achieved by cutting from large sintered blocks (mainly for small magnets).

Precautions for use

1. Consider the decrease of intrinsic coercivity at low temperature to avoid demagnetization.

2. A ferrite magnet is especially hard and fragile. When it is exposed to vibration or impacts, design the structure properly.

3. When thermal shock is applied to a magnet, magnet breakage may occur. Never expose a magnet to thermal shock such as a rapid heating or cooling speed.

4. If magnets rub against each other during transportation, magnet powder may be seen on the surface.