Ndfeb magnetNd-fe-b is currently found to be the most commercially available magnet, known as the magnetic king. It has extremely high magnetic energy and its maximum magnetic energy product (BHmax) is more than 10 times higher than that of Ferrite. Its own mechanical processing performance is also quite good. The working temperature can reach up to 200 degrees Celsius. And its quality is hard, performance is stable, have very good cost performance, therefore its application is extremely wide. But because of its strong chemical activity, it must be coated.

      Ndfeb permanent magnet is based on intermetallic compound Nd2Fe14B. Relative to the cast al-ni-co permanent magnet and ferrite permanent magnet, ndfeb has extremely high magnetic energy accumulation and coercivity, and can absorb mass equal to 640 times its own weight. Due to the advantages of high energy density, nd-fe-b permanent magnet materials have been widely used in modern industry and electronic technology, which makes it possible to miniaturize, lightweight and thin equipment such as instruments, electroacoustic motors and magnetic separation magnetization. Material characteristics of nd-fe-b are the advantages of high ratio of performance, good mechanical characteristics, easy to cut processing; The disadvantage is that the Curie temperature is low, the temperature characteristics are poor, and the powder corrosion is easy to be made, and it must be improved by adjusting its chemical composition and adopting surface treatment method to meet the requirements of practical application.
Manufacture process of ndfeb powder metallurgy process, will contain a certain proportion of raw materials such as: dysprosium, neodymium, iron, cobalt, niobium, praseodymium, aluminum, iron boron by medium frequency induction melting furnace smelting alloy ingot, and then broken into 3 ~ 5 microns powder, and forming technology in the field, the forming of the green compact sintering in vacuum sintering furnace and tempering time, thus obtained a certain magnetism of permanent magnet blank. After grinding, drilling and slicing, the finished product is obtained by surface treatment.
The length and volume of the air gap in the working process of the motor are varied, which belong to the dynamic magnetic circuit. The magnet is not only affected by the temperature change, but also affected by the armature electromotive force on its reverse demagnetization. As the working point changes back and forth on the reply line, the magnet is in a state of circular demagnetization. This requires us to consider not only the influence of temperature change, but also the additional influence of dynamic demagnetization when designing the magnetic circuit of the motor. For general power dc motors, due to armature effect, the lowest operating point is about -0.6. At this point, the b-h curve of the magnet is required to be a straight line under the continuous operating temperature of the motor. If the b-h curve is bent, the magnet will generate permanent demagnetization due to armature effect. In addition, under the limit temperature of the motor, the irreversible loss of the magnetic flux of the magnet is required to be less than 5%.
Nd-fe-b permanent magnet is mainly used in micro-motor, permanent magnetic instrument, electronic industry, automobile industry, petrochemical industry, nuclear magnetic resonance device, acoustic equipment, magnetic levitation system, magnetic transmission mechanism and magnetic therapy equipment, etc., and can also be used in magnetization of oil routes of motorcycle and automobile to save oil.
The third generation of rare earth permanent magnet NdFeB (NdFeB) is the strongest performance of permanent magnet in contemporary magnets, it not only has high remanence, high coercive force, high magnetic energy product and high performance price ratio features such as, and easily processed into a variety of sizes, is now widely used in aviation, aerospace, electronics, electro-acoustic, mechanical and electrical, instruments, meters, medical technology and other needs of permanent magnetic field of the equipment, especially suitable for the development of high performance, miniaturization, light-duty and upgrading of products.