Microstructure of Zr containing NdFeB

Simultaneous additions of Co, Al, and Zr to Nd(Dy)FeB alloys substantially improve the coercivity and corrosion resistance, and somewhat increases the Curie temperature. It was found that the microstructure of starting materials affects the final magnetic properties of the resulting sintered magnets. A cast ingot having /spl alpha/-Fe with Nd/sub 2/Fe/sub 14/B, Nd-rich and Zr-rich phases has generated higher coercivity than a homogenized ingot without /spl alpha/-Fe. This may be explained by the grain boundary phase change of the resulting sintered magnets.