Raw Materials and Manufacturing
They are mainly made from SrO (strontium oxide) or BaO (barium oxide) and Fe₂O₃ (iron oxide) as raw materials through powder metallurgy and other methods. They belong to sintered permanent magnetic materials and are composed of barium and strontium ferrites.
Physical Properties
1. Hardness and Brittleness
They are hard and brittle. This requires special mechanical processing techniques during processing. However, they can be cut and processed using abrasive tools like carborundum tools.
2. Energy Product
The energy product ranges from 1.1 MGOe to 4.0 MGOe. Compared with some other permanent magnets, their magnetic energy is relatively low.
Magnetic Properties
1. Demagnetization Resistance
They have strong demagnetization resistance, are not easy to be demagnetized, have a relatively large coercive force, and strong anti-demagnetization ability. They are especially suitable for use in magnetic circuit structures under dynamic working conditions.
2. Magnetization Characteristics
They are divided into anisotropic and isotropic types. The magnetic performance of isotropic sintered ferrite permanent magnetic materials is relatively weak, but they can be magnetized in different directions of the magnet; while the anisotropic sintered ferrite permanent magnetic materials have relatively strong magnetic performance, but they can only be magnetized along the predetermined magnetization direction of the magnet. Anisotropic magnets must be magnetized along the manufacturing direction because they are oriented along that direction, while isotropic magnets can be magnetized in any direction since they have no orientation (although a slightly stronger magnetic induction is often found on the smaller compression surface).
Other Characteristics
1. Corrosion Resistance
Since the main raw materials are oxides, they have the advantage of being not easy to corrode.
2. Production Process and Cost
The production process is relatively simple and the cost is low. This leads to a relatively high production volume in the entire magnet industry and broad application fields. They are widely used in many fields such as motors, speakers, toys, and handicrafts.
3. Working Temperature Range
The working temperature ranges from -40 °C to +200 °C, and they can perform their functions normally within this temperature range.
4. Reversible Permeability
They have a relatively low remanence and a small reversible permeability.
