Effects of compositions on characteristics and microstructures for melt-spun ribbons and die-upset magnets of Nd12.8+xFe81.2-x-y-zCoyGazB6

The effects of varying Nd-contents on the magnetic properties of Nd12.8+xFe81.2-x-y-zCoyGazB6 ribbons and the resulting die-upset magnets have been investigated. It was found that the Nd content has a significant effect on both magnetic properties and texture of the die-upset magnets. An optimum Nd content exhibits good texture, while both Nd-lean and excessively Nd-rich Nd-Fe-B alloys lead to unsatisfactory textures. The magnetic properties and texture of the die-upset magnets strongly deteriorated with a further increase in the Nd-content. The thermo-mechanical characteristics and the formation mechanism of two kinds of cracks in backward-extruded ring magnets have also been investigated.