Nd-Fe-B sintered magnet is an indispensable key component in the driving motors of hybrid electric vehicles and electric vehicles. Compared with other magnets, Neo magnets
not only have the strong magnetic force and can achieve high power enough to drive the vehicle, but also can reduce the motor to the size suitable for vehicle use.
So, do you know how this Nd-Fe-B magnet is made? It needs to crush the alloys containing the necessary materials into particles, aggregate these particles to form, and then sinter. Then cut to the required size to complete. This process always feels like making a cake.
Of course, it is not so simple to produce high-quality Nd-Fe-B high-strength magnets in actual quantities. It takes a lot of time to unify the particle size from 3 to 5 microns, to pay attention to the uniformity of the shape, and to consider the heating method during sintering. "By accumulating a large number of small technologies, we have reached today's practical level" (technicians engaged in the development of Neo magnets.
For example, one of them is the process of forming in a magnetic field after crushing the alloy to 3-5 microns. The process is to align the crushed micro-powder (micro-magnet). The orientation here refers to unifying the magnetization direction of the powder into a fixed direction. The higher the orientation, the greater the residual magnetic flux density (the index of magnetic field intensity). In this process, the micro-powder is filled into the mold, the orientation of the micro-powder is carried out by applying a strong magnetic field, and then the pressure forming process is carried out. The uniqueness of this method is that it is formed under gentle pressure to the extent that the molding body will not collapse. Because of the pressure is too high, it will disturb the uniform orientation of fine powder.
In order to achieve high orientation, it is also important to create a uniform magnetic field space inside the die. Because the configuration of the electromagnet and the size, shape, and material of the die will make the magnetic field uneven, leading to poor orientation, it is necessary to use magnetic field analysis and other means to fine-tune, so as to make the magnetic field uniform.