Researchers at the National Research Council of Canada (NRC), Ottawa, have reportedly developed a method to produce permanent magnets for electric motors by cold spray metal additive manufacturing. Fabrice Bernier and Jean-Michel Lamarre, the team who developed the new method, think this technology could make it possible to produce magnets in complex shapes and for complex parts without the need for assembly.
Currently, high-performance magnets in electric motors are typically made by processes such as powder compaction for sintered magnets, or injection molding for bonded magnets. In these processes, magnets must first be fabricated and then shaped and assembled into a final product. The NRC’s cold spray technology is said to combine all the steps into one, and could lead to significant cost reductions. It also opens up a world of design possibilities not achievable with traditional manufacturing processes.
The cold-sprayed magnets also have excellent mechanical and thermal properties. The high velocities of the powder deposition and the absence of polymer in the material matrix are said to give the magnet mechanical properties superior to those of conventional magnets, including increased thermal conductivity and resistance to corrosion and oxidation.
The adhesion of the magnetic material to the surface of the part is also exceptional, since neither glue nor assembly is needed. In addition, magnets fabricated by cold spray AM are easier to machine than more brittle sintered magnets.
