Effect of DyHx addition on the magnetic properties and microstructure of Nd14.1Co1.34Cu0.04FebalB5.84 magnets

The sintered Nd14.1Co1.34Cu0.04FebalB5.84 permanent magnets with DyHx addition have been prepared by powder-blending technique. The magnetic properties and microstructures of the magnets were investigated. It was found that Dy element is enriched in the intergranular phase, being evenly distributed throughout the grain boundary and improving the orientation of magnets as a lubricant, and 1.2% to 2% DyHx additions are proved to be very effective in improving the permanent magnetic properties of Nd14.1Co1.34Cu0.04FebalB5.84 magnets. Further analysis revealed that the increase of coercivity and slight decrease of remanence due to DyHx addition can be attributed to the reduction of the primary phase volume, formation of the (NdDy)-rich phase and grain refinement of the main phase.