Many different kinds of magnets, generally divided into two types: permanent magnets and soft magnets. What we call the magnets, generally refers to the permanent magnets. Permanent magnets divides into two major categories:
The first major categories are: metal alloy magnets including neodyimium magnet (NdFeB, Nd2Fe14B)  , samarium cobalt magnet (SmCo), aluminum nickel cobalt magnet (ALNiCO). The second major categories are: Ferrite permanent magnet (Ferrite)

1. Ndfeb magnets: it is found that the highest performance magnets Known as the king of magnets, has the extremely high magnetic to its maximum magnetic energy product (BHmax) above Ferrite (Ferrite) more than 10 times. Machining properties of its itself is also quite good. Working temperature up to 200 degrees Celsius. And the quality of a material is solid, stable performance, good cost performance, so its application is very extensive. But because of its chemical activity is very strong, so you have to handle with coating on the surface layer. (such as zinc plating, Ni, electrophoresis, passivation, etc.

2.Ferrite magnets: it is the main raw material includes BaFe12O19 and SrFe12O19. Manufactured by ceramic technology, the quality of a material is hard, brittle material, because of the ferrite magnets have good temperature resistance, low cost, moderate performance, has become the most widely applied permanent magnets…..See category of ferrite magnet.

3.Alnico magnets: is made from aluminum, nickel, cobalt, iron and other trace metal elements. Casting process can make Alnico into different sizes and shapes, machinability is good. Casting aluminum nickel and cobalt permanent magnet has the lowest reversible temperature coefficient , working temperature can be as high as 600 degrees Celsius above. Alnico permanent magnet products are widely used in all kinds of instruments and meters and other application fields.

4.divided into SmCo5 and Sm2Co17. Because its material is expensive and make its development was restricted. Samarium cobalt (SmCo) as a rare earth permanent magnets, not only have higher magnetic energy product (14 to 28 MGOe), reliable, coercive force and good temperature characteristics. Compared with the ndfeb magnets, samarium cobalt magnet is more suitable for working in high temperature environment.