Effects of C and Ti additions on the microstructures of Nd9Fe77B14 nanocomposite magnets

The effect of Ti and C additions on the microstructures and the magnetic properties of Nd–Fe–B isotropic nanocomposite processed from Nd9Fe77B14, Nd9Fe73B14Ti4 and Nd9Fe73B12.6C1.4Ti4 (numbers indicate at.%) alloys has been investigated by transmission electron microscopy and three-dimensional atom probe techniques. The grain size was substantially refined by the addition of Ti due to the formation of Ti-enriched amorphous grain boundary. Further addition of C enhanced the enrichment of Ti in the grain boundary phase, which led to the increase of coercivity and maximum energy product.