Permanent magnet materials are an important functional material with energy and information storage and conversion functions. More than two thousand years ago, people discovered that iron ore (Fe3O4) in nature has attractive characteristics. At that time, people called it "magnet." In the year of 1080 AD, the invention of the compass was the earliest practical application of permanent magnet materials. The permanent magnet materials that humans can produce in large quantities are just a variety of hardened martensitic steels. An alloy of Fe2AlNi appeared after 1931, and an AlNiCo permanent magnet alloy was gradually formed by the addition of Co. These permanent magnet materials have a coercivity of only a few hundred Oersted. The ferrite permanent magnet material has a high coercive force and has a uniaxial hexagonal crystal system. At this point, people's understanding of permanent magnet materials has made important developments: in order to obtain high coercivity permanent magnet materials, it is necessary to have a large magnetocrystalline anisotropy. Although Fe, Co, and Ni of VIII in the periodic table have strong exchange effects and high magnetic order temperature, since the 1960s, intermetallic compounds formed by rare earth metals and 3d transition metals have been used as matrix. Permanent magnet materials have become an important material basis for the high-tech multi-functional and intelligent new technology industry. The rare earth permanent magnet is divided into: samarium cobalt 1:5 (SmCo 5 ), samarium cobalt 2:17 (Sm 2 Co 17 ) and neodymium iron boron (Nd 2 Fe 14 B). In 1983, at the 29th World Magnetic Conference in Pittsburgh, Sagawa and others of Sumitomo Special Metals Co., Ltd. announced the invention of the "NdFeB" rare earth permanent magnet material, and the third generation rare earth permanent magnet material was born. NdFeB is the most prominent advantage of traditional permanent magnet materials because of its high magnetic properties. It is known as the ¡°permanent magnet king¡±.

Tags: neodymium magnets neodymium magnet neodymiummagnets Smco magnets