The effect of Co addition on the fracture strength of NdFeB sintered magnets

The bending strength and fracture toughness of the ternary and Co-containing NdFeB sintered magnets have been studied. The microstructure and the fracture behavior were examined utilizing micro-analysis. It is shown that the bend fracture of the NdFeB magnets is mainly intergranular. The Co addition with proper content increases the bending strength of NdFeB sintered magnets by about 80% and this is mainly due to the strengthening of Nd-rich grain boundary phase.