Magnetic materials are functional materials of ancient and very wide range of uses, the magnetism is recognized and applied 3000 years ago, for example Chinese ancient natural magnet used as a compass. Magnetite exists widely in nature, is a natural magnet, the molecular structure of Fe3O4. in recent years, with the development of industry and technology, a large number of new magnetic materials were found, according to the main application is roughly divided into three generations: the first generation is aluminum nickel cobalt (AlNiCo magnet
), the second generation is hard ferrite magnet(also called as ceramic magnets), the third generation is rare earth permanent magnet(including SmCo magnets and neodymium magnets). The rare earth magnet is divided into three stages: the first stage SmCo5 magnets, second stage Sm2Co17 magnets, third stage Nd2Fe14B(that is NdFeB magnets or neodymium magnets)
The following is a brief history of the development of magnetic materials(known as permanent magnets):
First Century B.C.:Sima Qian, < < historical records > > describes the battle of Yellow Emperor that uses compass.
In the year 1086,the Song Dynasty Shen Kuo "MengXiBiTan > remember compass manufacturing method etc.
In the year 1119,The Song Dynasty "Zhu" or "Ping Chau" can be talked about. The record compass is used for navigation
In the year 1600,British William.Gibert, the earliest work of the
In the year 1820,H.C.Oersted first discovered that current could produce a magnetic field.
In the year 1822,The French lussac invented electromagnet, i.e. the current through the winding can magnetize iron block.
In the year 1826,French ampere discovered Abe's law, that is, the right-hand spiral rule.
In the year 1831,Faraday demonstrated the phenomenon of electromagnetic induction and revealed the relationship between electric and magnetism.
In the year 1832,The French A.H. pixii invented permanent magnet AC generator rotating made by natural magnets.
In the year 1931, Japan T.Mishima invented AlNiCo magnets.
In the year 1933,ferrite magnet Co containing Fe2o3 was found in Kato and Takei, Japan
In the year 1935,soft ferrite magnets invented by SNoek in Holland.
In the year 1965,CoP ferromagnetic amorphous alloy was prepared by Mader and Nowick.
In the year 1967,the discovery of type 1:5 SmCo magnet in the United States of America marked the arrival of the era of rare earth permanent magnets (the third generation of magnetic materials) .
In the year 1977,Japanese Ojima found 2:17 type SmCo magnets and contained a small amount of Cu, Zr.
In the year 1983,Japan Sagawa discovered Nd2Fe14B, NdFeB magnet known as the contemporary magnet king.
In the year 1983,General motors of the United States, followed Japan discovered neodymium iron boron magnet, each has a patent, that is patent magnets.
In the year 1984, NdFeB magnets with magnetic energy product exceeding 35MGOe have been developed by China National Iron and Steel Research Institute.
In the year 1992, China neodymium magnets factory purchased Sumitomo NdFeB patent.
In the year 2002,China's annual output of NdFeB magnet/neodymium magnet has reached 8000 tons, surpassing Japan as the first in the world.
In the year 2008,China NdFeB magnet producer reached more than 100, with an annual output of 46000 tons neodymium magnets.
Since the year of 2008,since the inception of NdFeB magnet laboratory has more than 30 years, due to the rare earth is expensive, especially under the influence of heavy rare earth terbium dysprosium shortage, countries in the world are competing to develop a new generation of magnetic materials, such as samarium iron nitrogen permanent magnetic nanocomposite rare earth permanent magnet, but the effect is still not ideal, neodymium-iron-boron magnet in the next ten or twenty years, the status is still unshakable.