Anisotropic NdFeB hard magnets by MIM

Hard magnets made from NdFeB play an important role in modern industry as they supply the magnetic energy in almost all applications where minimum weight and volume combined with maximum energy product is needed. They are the main reason why rare earth elements have been rated as a rare and strategic commodity, recently. NdFeB magnets are always produced from powder, mainly by CIP or uniaxial pressing plus sintering. Despite some early patents to also produce them by MIM no commercial production has taken place. The study presented here shows that NdFeB hard magnets produced by MIM reach properties easily comparable to CIP magnets. The influence of process parameters on the magnetic properties, additionally the effect of the direction of magnetisation upon the shrinkage of the magnets was analysed. An assessment of the potential of MIM in the market of hard magnets is given.