Prepared by melt-spinning process of NdFeB magnetic powder. Will be quenched by the alloy ribbon made of powder products can be quenched directly from the powder. The following three methods can be made of magnetic practical permanent magnet: The isotropic bonded magnets bonded into the legal system; with hot isotropic pressing method into dense magnets; with the legal system into a thermal processing thermal deformation anisotropic deformation magnet. Quenched NdFeB magnetic alloy Comparison of three magnets. If the thermal deformation of anisotropic permanent magnet crushing, grinding into the magnetic points, and then use it made of anisotropic bonded magnet.
Preparation of NdFeB melt-spinning with a twin-roll thin and single roller method two. Vacuum single-roller rapid quenching method method of production equipment. Induction loop in NdFeB quartz crucible heating and melting a master alloy melt by argon gas pressure regulating valve will melt from the crucible bottom of the narrow high-speed direct injection into the surface of rotating copper roll. Copper roller can be cooled through the cooling liquid, or use their own good thermal conductivity, will jet to the surface of the magnetic alloy liquid cooling speed of 10 to 20. In the copper roller diameter and the temperature under certain conditions, copper roller speed or surface speed is proportional to its cooling rate. Prepared by single roll thin strip of the thickness of NdFeB 30 ~ 80UM, generous to 1 ~ 3MM, length depends on the capacity of the crucible. Preparation of NdFeB alloy quick-setting process In the traditional metal mold ingot process, thinning the thickness of ingots to be effective in refining grain size. However, the Ministry of the ingot center and surface of the cooling conditions are very different, for the NdFeB alloy is still difficult to eliminate A-FE precipitation. The elimination of the magnetic alloy of the A-FE is to obtain high performance sintered NdFeB magnet important means. To this end, in 1995, who developed the so-called quick-setting ingot process.
Accelerating the basic principles of casting and rapid quenching method similar to the magnetic alloy melt is cast into a certain water-cooled copper roller speed, in the 102 to 104 of the cooling rate to form a thickness of 0. 03 ~ 10MM range magnetic alloy sheet. Shenyang Vacuum Technology, North VI-SC developed a new series of quick-setting principle of vacuum melting. It consists of induction melting crucible, tundish, rotating cooling roller, turn the cooling container assembled in a large vacuum container and vacuum unit and its external intermediate frequency power supply connections. Loading in the smelting crucible, the frequency power supply connected to the magnetic alloy material melting, the magnetic iron alloy by electromagnetic stirring solution of uniform structure, to be magnetic alloy to reach the required temperature, the magnetic alloy liquid flow into the middle of a certain package. Intermediate frequency power supply connected with the package is also to ensure that the magnetic alloy tundish fluid to maintain a constant temperature, while maintaining a constant tundish magnetic alloy surface to a certain velocity and flow of the magnetic alloy liquid injection to a certain speed of rotation cooling roller surface, it will stretch a certain thickness of the melt pool of quick-setting thin strip, which scales the ingot. SC into the rotation and the cooling container, the SC cooling to a certain temperature in order to avoid adhesion between the SC.
Rotating roller by a reasonable choice of materials and cooling capacity to control the microstructure of the ingot scale, so that ingot memory in A-FE, there is no Nd-rich phase of block, there is no small equiaxed zone or amorphous , so that the ingot can be prepared with the required high performance sintered NdFeB magnet microstructure. NdFeB alloys prepared using different ingot casting process and the corresponding results of chemical analysis of the magnetic properties of sintered magnets. Preparation of quick-setting process can be seen the scales with homogeneous, fine grain, non-A-FE, Nd-rich phase uniformly dispersed around the main phase and around the advantages of sintered magnets obtained significantly better than the magnetic properties of magnetic alloy systems Wei ingot obtained in the magnet. In addition, also found that the scales in the atmosphere the oxygen content of only 20 days after placing 120X10, that scale has a certain antioxidant capacity, suitable for large-scale production of neodymium iron boron magnets.