Method for producing a rare earth-based magnet

摘要

A method of diffusing a rare earth element into a plurality of sintered magnets 4 which comprises a R2Fe14B phase (where R is a rare earth element). Particles 1 comprising a rare earth element R' are applied to a surface 3 of each magnet 4 and particles 2 of further material are also applied to a surface 9 of each magnet 4 . The magnets 4 are arranged such that particles 1 comprising R and particles 2 of the further material are positioned between adjacent magnets 4 â and then the magnets 4 heat treated at a temperature and for a time selected to allow diffusion of R' into adjacent magnets 4 while the further material remains solid and particulate. The particles 1 containing R can be a hydride, an alloy or a hydrogenated alloy and the further material can be a rare earth oxide. The particles 1 & 2 can be applied as a mixed paste (Fig. 1) or as separate pastes (Fig. 4).