THERMOMECHANICAL TREATMENT AND HEAT-TREATMENT OF ND2.5FE13COC1.425B0.075 BULK MATERIAL

Nd2.5Fe13CoC1.425B0.075 is considered as new permanent magnet material of technical interest. Time-temperature-transition diagrams were inve stigated for 800, 850, 900 and 950-degrees-C. The starting microstruct ure consists mainly of dendrites of free iron with an intergranular Nd -rich phase. The desired Nd2Fe14B-type phase (PHI phase, tetragonal) f orms at the interfaces of iron/Nd-rich. After 15 min at 850-degrees-C more than 50% of the material consists of the PHI phase. The applicati on of a thermomechanical treatment (hot deforming) causes the PHI phas e crystallites to break and to align in the flow direction of the mate rial. A large amount of Nd-rich phase can be pressed out of the sample during deformation. Further experiments are necessary to prevent this . Another technique to obtain anisotropic bulk material is the heat tr eatment in a temperature gradient.