Magnetic properties and microstructure of NdFeB sintered magnets by the addition of Ag powder

NdFeB sintered magnets with the addition of Ag were prepared by blending hydrogen decrepitated NdFeB powder with Ag powder during ball milling. It was found that small additions of Ag powder increases the coercivity of the magnets without reducing the remanence. A microstructure study showed that oxygen content in the Nd-rich phase of the Ag-containing magnet is higher than that of the Ag-free magnet. This change in the composition of the Nd-rich phase increases the volume fraction of the Nd-rich phase in the Ag-containing magnet, which may be responsible for the increase of the coercivity