Structural and magnetic properties of heat-treated ultrafine single crystalline Nd2Fe14B particles obtained by ball-milling of dynamic hydrogenation disproportionation desorption and recombination powder

Isolated single crystalline Nd2Fe14B particles (200–500 nm) prepared by wet/surfactant-assisted ball milling were heat-treated at different temperatures under high vacuum, and structural and magnetic properties were investigated. Maximum coercivity values of 0.73 and 0.70 T were obtained after 400 °C heat-treatment for oleic acid and ethanol milled samples, respectively. With a further increase in the heat-treatment temperature the coercivity decreases. An increase in α-Fe and Nd2O3 phases and a sharp change of lattice parameter - c were observed when heat-treating above 400 °C.