R-T-B system permanent magnet

摘要: An R-T-B system permanent magnet 1 comprises a body 2 comprising sintered at least main phase R2T14B grains (wherein R represents one or more rare earth elements, and T transition metal elements including Fe Co essentially) grain boundary containing in larger amount than the phase, having 300 μm less thick (not inclusive of zero thick) hydrogen-rich layer 21 hydrogen concentration ppm formed surface portion, an overcoat 3 covering can improve corrosion resistance with thereon without degrading magnetic properties thereof. The present invention be applied to formation by electrolytic plating, fully ensure as primary target substantially production efficiency, provide high dimensional precision suppressing partial collapse (detachment grains)