Ferrite product introduction
The ferrite magnet is a sintered permanent magnet material composed of tantalum and niobium iron. In addition to strong anti-demagnetization properties, this magnetic material has the advantage of low cost. Ferrite magnets are rigid and brittle and require special machining processes. The opposite-sense magnets are oriented in the manufacturing direction and must be magnetized in the direction in which they are taken, while their isotropic magnets can be magnetized in any direction because they are not oriented, although a slightly stronger magnetic induction is found on the smallest side of the pressure-receiving surface. The magnetic energy product ranges from 1.1 MGOe to 4.0 MGOe. Due to its low cost, ferrite magnets have a wide range of applications, from motors and speakers to toys and crafts, making them the most widely used permanent magnet materials.
Ferrite features:
It is produced by powder metallurgy method, with low residual magnetism and low magnetic permeability.
It has large coercive force and strong anti-demagnetization ability, and is especially suitable for magnetic circuit structure used as dynamic working conditions.
The material is hard and brittle and can be used for cutting tools.
The main raw material is oxide, so it is not easy to corrode.
Operating temperature: -40 ° C to +200 ° C.
It is divided into anisotropic (isotropy) and isotropic (isotropic). The magnetic properties of isotropic sintered ferrite permanent magnet materials are weak, but can be magnetized in different directions of the magnet; Sintered ferrite permanent magnet materials have strong magnetic properties, but can only be magnetized along the predetermined magnetization direction of the magnet.
Ferrite physical properties
In the production of actual ferrite magnets, raw materials with good chemical composition may not necessarily obtain ferrite magnets with good performance and good microstructure, which are due to physical properties. The physical properties of the listed iron oxides include average particle size APS, specific surface area SSA and bulk density BD. Since the iron oxide accounts for about 70% of the MnZn ferrite magnet formulation, its APS value has a great influence on the APS value of the ferrite magnet powder. In general, the APS value of the iron oxide is small, and the APS value of the ferrite magnet powder is also small, which is advantageous for accelerating the speed of the chemical reaction. However, considering that the fine particles of the powder are not conducive to the subsequent pressing and sintering, the APS value should not be too small. Obviously, when the APS value of the iron oxide is too large, in the case of calcination, since the particle diameter is large, only the diffusion reaction of the spinel phase can be performed, and the grain growth process cannot be further performed. This inevitably leads to an increase in the activation energy required for sintering, which is disadvantageous for the solid phase reaction.
Ferrite performance parameter comparison table and physical characteristics
Ferrite use:
For speakers, pickups, recorders, etc.
Used in automotive motors: wipers, starters, heaters, fuel pumps, seat motors, etc.
Used in exercise bike magnetrons, massage chairs, automatic controls, microwave devices, radar and medical equipment.
Also suitable for making instruments, meters, micro motors, electro-acoustics, devices, copiers, magnetic actuators, etc.
