Effect of Titanium Substitution on Magnetic Properties and Microstructure of Nanocrystalline Monophase Nd-Fe-B Magnets

Nd12.3Fe81.7-xTixB6.0 (x = 0.5-3.0) ribbons have been prepared by rapid quenching and subsequent annealing treatment. Effect of Ti substitution and annealing treatment on the microstructure, magnetic properties, and crystallization behavior of the ribbons was systematically investigated by the methods of differential scanning calorimeter (DSC), X-ray diffraction (XRD), transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM). It is found that Ti addition may increase the crystallization temperature and stabilize the amorphous phase. Ti element inhibits the grain growth during crystallization process and finally refines the microstructure. The exchange coupling interactions and magnetic properties of the ribbons increase with increasing x from 0.5 to 1 and then decrease with further increasing x >= 1.5. Optimum magnetic properties with (BH)(max) = 151.6 kJ/m(3), H-ci = 809.2 kA/m, J(r) = 1.02 T are achieved in the Nd12.3Fe80.7Ti1B6.0 ribbons annealed at 600 degrees C for 10 min.