Method for preparing sintered neodymium iron boron magnets in 3D cold printing mode

Abstract

The invention provides a method for preparing sintered neodymium iron boron magnets in a 3D cold printing mode and belongs to the field of powder metallurgy. By wrapping the surfaces of neodymium ironboron magnetic powder with layers of oxygen-free organic film, the magnetic powder is prevented from being oxidized in the 3D cold printing process, meanwhile, printing slurry is prepared by adoptinga low-molecular-weight and low-oxygen gelatin system, printing orientation forming of the magnets is achieved through magnetizing, and after isostatic cool pressing and sintering are performed, sintered neodymium iron boron parts in complex shapes are finally obtained. Oxygen-free organic matter is adopted for wrapping the surfaces of the neodymium iron boron powder which is oxidized easily, theoxidation problem of the magnetic powder in the forming process is controlled, the 3D cold printing neodymium iron boron slurry is prepared by adopting the low-molecular-weight and low-oxygen gelationsystem, and the oxygenation situation of the magnets in the forming process are further controlled. The sintered neodymium iron boron magnets prepared through the method provided by the invention have the good magnetic performance, near-net forming of all complex shapes can be achieved, cutting machining of magnet complex parts is omitted, the production cost is greatly lowered, and resources aresaved.

Description

technical field [0001] The invention belongs to the field of powder metallurgy and provides a method for preparing sintered NdFeB magnets by 3D cold printing. Background technique [0002] Sintered NdFeB permanent magnet material is called "Magnetic King" because of its high energy density. It has become a core functional device in the fields of aerospace, biomedicine, information communication, household appliances, wind power generation and automobile industry. Among them, heavy rare earth Dy or Tb is an element commonly used in high-performance sintered NdFeB magnets. However, heavy rare earth Dy and Tb elements are scarce and expensive. Sintered NdFeB magnets are usually prepared by powder pressing and sintering processes, but in order to obtain parts with ideal shapes, a certain amount of machining is usually required on the sintered magnets, which causes a lot of waste of resources and increases production costs. Therefore, it is necessary to develop a technology tha...

AI Technical Summary

Problems solved by technology

For sintered NdFeB magnets, the particle size of the powder is generally 3-8μm, if the grain size is too large, the magnetic properties of the magnet will be greatly reduced

Therefore, high energy beam sintering rapid prototyping technology is not suitable for the preparation of sintered NdFeB magnets