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The third generation of rare earth permanent magnet ndfeb magnets, rounding _ ndfeb strong magnet manufacturers

by:Newland     2020-04-06
Human understanding of rare earth permanent magnet materials from Leningrad, 1935 scientists in the journal Nature of a short essay 'has more than 340 ka/m Nd - coercive force Fe materials. Rare earth permanent magnet materials since the 1960 s, has experienced three stages, namely, the first generation ( 1:5 SmCo5) And the second generation ( Which type Sm2Co17) And the third generation ( 钕铁硼) 。 Rare earth is a chemical element in the periodic table - lanthanide elements - - - - - - - - - - - - Lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium, and the two are closely associated with lanthanide elements - - - - - - - - - - - - - Scandium and yttrium, a total of 17 elements. Was originally found in Sweden's relatively scarce mineral, & quot; Soil & quot; Was the physical habit of calling on insoluble in water, therefore calls the rare earth. After the second world war, with the development of rare earth elements separation technology and low temperature, low temperature properties of rare earth elements was studied, and found that most strong magnetic rare earth elements in low temperature, but because of the Curie temperature lower than at room temperature, therefore cannot be directly made into permanent magnetic material. Considering the elements such as iron, nickel and cobalt at room temperature has a strong magnetic, people began to research using rare earth and alloy of iron, cobalt, can improve the rare earth elements in room temperature magnetic. 1959 GdCo5 alloy has strong magnetocrystalline anisotropy, YCo5 alloy were found in 1966, in 1967, the American scholar K. J。 Strant et al. developed the magnetic energy product for 5 mgoe SmCo5 powder bonded permanent magnetic material, become the first generation of milestone of the birth of a rare earth permanent magnet materials, 1968 ordinary milling method is used to manufacture the SmCo5 magnetic energy product is 8 mgoe, static pressure technology on the same year, produce magnetic energy product of 17. 5 mgoe SmCo5 permanent magnets. Using liquid phase sintering process for the first time in 1970 manufacturing SmCo5 permanent magnets, so that the manufacture technology of SmCo5 to gradually perfect and mature. In 1977, the Japanese T. Ojima et al. , using the method of powder metallurgy developed magnetic energy product for 30 mgoe Sm2Co17 permanent magnetic material, marks the birth of the second generation of rare earth permanent magnet materials. Because of SmCo5 contains about 66% Co, and Co is expensive strategic elements. So SmCo5 appeared, people started to consider Co substitution materials in 1983, Japan's sumitomo special metals company developed the magnetic energy product by powder metallurgy method is 36 mgoe NdFeB permanent magnet material, gm also announced the successful development of the NdFeB NdFeB strong magnet marks the birth of the third generation of rare earth permanent magnet NdFeB material. Ndfeb permanent magnets with rare earth element neodymium instead of samarium cobalt permanent magnet of samarium ( In the rare earth mine, the content of neodymium 5 ~ 10 times of samarium) 。 Cobalt and contains no material as this is what people study new permanent magnet materials goal. In 1995, NdFeB permanent magnet magnetic energy product has reached to 51. 2 mgoe, with fast hardening and hot extrusion method in the production of the anisotropy of quick quenching magnet magnetic energy product has reached 40 mgoe, made of reduction diffusion method NdFeB magnetic energy product reach 36 mgoe. In 1987, Japan's sumitomo special metals company announced the magnetic energy product of 50. Successfully developed six mgoe NdFeB magnet; In 1990, researchers at Japan's northeast metal company claims can get magnetic energy product is 52. 3 mgoe NdFeB magnets, in 1993, made the world's highest sumitomo special metals company announced NdFeB magnet magnetic energy product! Magnetic energy product for 54 mgoe. The main composition of ndfeb permanent magnet is Nd2Fe14B, is the strongest permanent magnet magnetic materials. The maximum magnetic energy product of up to 398 kj/m3 for 5 ~ 12 times of ferrite permanent magnet materials, aluminum nickel and cobalt permanent magnet 3 ~ 10 times, the theoretical value of 527 kj/m3; Remanent magnetism of up to 1. 47 t, coercive force up more than 1000 ka/m, can suck up the equivalent of a weight of 640 times its own weight. Because do not contain cobalt and neodymium in rare earth content is more than ten times that of samarium, summary of rare earth cobalt prices are much lower. Ndfeb magnet low Curie temperature! For 310 ~ 410 ℃ temperature stability is poorer, remanence temperature coefficient is - ( 0. 095-0. 15) % / K, coercive force for - temperature coefficient ( 0. 4 to 0. 7) % / K, usually the highest working temperature is 150 ℃, the new magnetic electronics now provides 200 ℃ high temperature resistant ndfeb permanent magnets, room temperature demagnetization curve is linear, but the heat causes the bending of the lower part of the demagnetization curve if poorly designed, prone to irreversible demagnetization. Ndfeb strong magnet contains a lot of neodymium, iron, and is easy to rust, poor chemical stability, its surface is usually need to do plating processing, such as zinc, nickel, tin, silver, gold, etc. , can also do phosphating treatment or coating to slow down the oxidation rate of epoxy resin, coating thickness is usually 10 ~ 40 & mu; m。
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