Commercialization of it is currently highest performance magnet, known as the King of magnetic, has a very high magnetic properties of the maximum energy product (BHmax) higher than ferrite (Ferrite) more than 10 times. Its own mechanical processing performance is also very good. Operating temperatures of up to 200 degrees Celsius. But its hard, stable performance, there is a very good price, so its application is extremely extensive. But because of their chemical activity is very strong, so it must deal with the tinted layer on its surface. (Such as Zn,Ni coating, electrophoresis, passivation).