Influence of heat treatment on structure and properties of cast magnets of the Nd-Ge-C system alloyed by copper

The structure-phase transformation after heat treatment and Cu-doping of Fe66Cu2Nd20C9.5B0.5 cast alloy is investigated in a present work. For Fe66Cu2Nd20C9.5B0.5 alloy preparation, constituent elements are inductively melted under argon atmosphere. The magnets are prepared by the annealing of ingots. As revealed, complex processes of main-elements' dilution are occurred after Nd-Fe-C-magnets' annealing. Such processes lead to the optimal-microstructure formation at annealing temperature 950degreesC. As shown, during annealing-temperature enhancement, coercivity correlates with NdsFe14C and Nd2Fe17 phases' microhardness and lattice-parameters' change. In Cu-doped alloys after annealing during 5 h at 950degreesC, coercivity is raised up to 880 kA/m and residual induction up to 0.58 T. The Cu addition to Nd-Fe-C alloys appears to be a promising way for high-coercivity magnets' production.