Rare Earth Permanent Magnet Material

Before understanding rare earth permanent magnet materials, we need to understand what is permanent magnet material? As the name suggests, permanent magnet materials can be understood as always magnetic materials, which are essentially materials that can maintain constant magnetism after magnetization, such as natural magnets in nature. We called it "Si Nan" in ancient times. For the description of permanent magnet, the earliest seen in the Spring and Autumn period "Guiguzi" "Zheng people take jade also, carrying the car of Sinan"; "On Heng" in the Eastern Han Dynasty, "the ladle of Si Nan, into the land, its end guide".

The development of permanent magnet materials has experienced metal permanent magnet materials, ferrite permanent magnet materials and rare earth permanent magnet materials.

Metal permanent magnet material stage: around 1880, the first carbon steel made of metal permanent magnet material, after the development of tungsten steel, cobalt steel and other permanent magnet materials. In 1931, iron-nickel aluminum alloy was developed in Japan, and elements such as cobalt, copper and titanium were added to form the famous AINiCo magnet. Since then, AINiCo magnet has occupied a dominant position in metal permanent magnet materials until the 1960s.

Ferrite permanent magnet material stage: also known as permanent magnet ferrite, with strontium oxide or barium oxide and ferric oxide as raw materials, made by ceramic process. Ferromagnetism is permanent magnetism because the magnetic moments of some iron ions are antiparallel to each other. The chemical formula of the current mainstream permanent magnet ferrite in the market is MO·6Fe2O3, in which M is barium, lead, strontium and other elements. Because of its low price and simple technology, it developed rapidly in the 1970s.

Rare earth permanent magnet material stage: The alloy composed of samarium, neodymium mixed rare earth metals and transition metals (such as cobalt, iron, etc.) is pressed and sintered by powder metallurgy method and magnetized by magnetic field to produce a magnetic material. Including: Samarium cobalt (SmCo) permanent magnet, NdFeB permanent magnet. The magnetic energy of NdFeB magnet is more than 100 times higher than that of magnetic steel. It is the highest magnetic permanent magnet material at present, so it is called "permanent magnet King".

NdFeB permanent magnet is actually the third generation of rare earth permanent magnet in the development stage. It was jointly developed by the United States and Japan in 1982 and realized industrial mass production in 1983. It can be said that NdFeB permanent magnet is a major revolution in the field of permanent magnet materials.

Good technology and products must be born to meet the needs of the market. From the demand side, NdFeB permanent magnets are widely used in high-tech industries such as wind power generation, new energy, energy-saving home appliances, industrial robots and high-speed rail/maglev trains.