NDFEB SYSTEM SINTERED MAGNET AND METHOD FOR PRODUCING THE SAME

摘要

Provided is a NdFeB system sintered magnet which can be used in the grain boundary diffusion method as a base material in which R H can be easily diffused through the rare-earth rich phase and which itself has a high coercive force, a high maximum energy product and a high squareness ratio, as well as a method for producing such a NdFeB system sintered magnet. A NdFeB system sintered magnet according to the present invention aimed at solving the aforementioned problem is characterized in that the average grain size of the main-phase grains in the NdFeB system sintered magnet is equal to or smaller than 4.5 µm, the carbon content of the entire NdFeB system sintered magnet is equal to or lower than 1000 ppm, and the percentage of the total volume of a carbon rich phase in a rare-earth rich phase at a grain-boundary triple point in the NdFeB system sintered magnet to the total volume of the rare-earth rich phase is equal to or lower than 50 %.