Applied Magnets 10 of Ceramic Magnets

Ferrite magnet is a Ceramic Magnet material, which is composed of barium and strontium iron. In addition to strong demagnetization resistance, this kind of magnet has the advantage of low cost. Ferrite magnet is hard and brittle, which needs special machining technology. Heterotropic magnets, because they are oriented in the direction of manufacture, must be magnetized in the direction taken, while homogenous magnets, because they are not oriented, may be magnetized in any direction, although a slightly stronger magnetic induction is often found on the smallest side of the compression plane. The magnetic energy product ranges from 1.1MGOe to 4.0MGOe. Due to low cost, ferrite magnet has a wide range of applications, from motors, speakers to toys, crafts, so it is the most widely used Permanent Ferrite Magnet material.

characteristic:
The powder metallurgy method has low remanence and low recovery magnetic permeability. High coercivity, strong anti-demagnetization ability, especially suitable for dynamic working conditions of magnetic circuit structure. Hard and brittle material, can be used for emery tools for cutting processing. The main raw material is oxide, so it is not easily corroded. Operating temperature :-40℃ to +200℃. 
Ferrite magnets are divided into anisotropic (heterotropic) and isotropic (isotropic). The magnetic properties of the isotropic sintered ferrite materials are weak, but they can be magnetized in different directions of the magnet. Heteromorphic sintered ferrite Permanent Magnet materials have strong magnetic properties, but only along the intended direction of magnetization of the magnet. 

Physical property:
In the actual production of ferrite magnets, raw materials with good chemical composition may not be able to obtain ferrite magnets with good properties and microstructure sometimes, because of the influence of physical properties. The listed physical properties of iron oxide include mean particle size APS, specific surface area SSA, and loose density BD. As iron oxide accounts for about 70% in the formula of manganese zinc ferrite magnet, its APS value has a great influence on the APS value of ferrite magnet powder. Generally speaking, the APS value of iron oxide is small, and the APS value of ferrite magnet powder is also small, which is conducive to speeding up the speed of chemical reaction. However, the APS value should not be too small considering that the fine particle of powder is not conducive to post-process pressing and sintering easy crystallization. Obviously, when the APS value of iron oxide is too large, only the diffusion reaction of spinel phase can be carried out in the pre-firing process due to the large particle size, and the grain growth process can not be further carried out. This inevitably leads to the increase of activation energy required during sintering, which is not conducive to solid phase reaction. 

The main performance and grade parameters of Hard Ferrite Magnet

Range of applications:

Hard ferrites have high coercivity, so are difficult to demagnetize. They are used to make permanent magnets for applications such as refrigerator magnets, loudspeakers, and small electric motors.