Researchers at the US Department of Energy`s Center for Critical Materials Innovation, led by Ames National Laboratory, have developed a new method for manufacturing high-performance permanent magnets. This new “neo-anchor-coil magnet” process is a simple and commercially scalable process for creating nanoparticle-encased neodymium permanent magnets in stainless steel. According to Ames Institute scientist Jun Kui, the biggest challenge in making permanent magnets is making them more resistant to high-temperature magnetization. The second method is to manufacture small magnets by starting the manufacturing process with much smaller particles of magnetic material.
” There are two traditional ways of making magnets, explains Cui. One is to produce a large quantity of power of a specific size (usually 3 to 5 microns). Second, start with tiny powders that are nanometers in size instead of microns. For new magnets containing dysprosium, sintering involves heating the material to very high temperatures to solidify the magnet.
In the nanoparticle method, the powder does not contain dysprosium, but the powder must first be made very dense, then it undergoes a two-step thermal deformation process to solidify the magnet. Because these magnets remain air-sensitive after they are formed, they undergo a final plating process where they are coated with a layer of nickel. A new method developed by Cui and his team simplifies the process. Third, the coating step is omitted because the material remains in the stainless steel body throughout the process.
Finally, instead of a batch process, “a very long magnet can be produced continuously and then cut into a large number of smaller magnets,” says Cui.