Preparation and TEM-study of sintered Nd/sub 18/Fe/sub 74/B/sub 6/Ga/sub 1/Nb/sub 1/ magnets

Ga-doped Nd-Fe-B sintered magnets show an improved wetting behavior of the liquid phase during sintering and the formation of additional Ga-containing intergranular phases. Nb forms precipitates within the hard magnetic grains and enhances the coercivity. In the as-sintered magnets, a new Nd-rich Ga-containing region which contains Nd/sub 3/Ga and Nd/sub 5/Ga/sub 3/ is found. This region is formed from the liquid phase during cooling. In addition, the delta -phase occurs in the annealed magnets. Nb is found in the hexagonal NbFeB intergranular boride and in small Nb-containing precipitates within the hard magnetic phase. There is no Nb detected in the Nd-rich phases.<
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