| Summary: | In this work, the mechanochemical synthesis method was used for the first time to produce powders of the nanocrystalline Nd<sub>1.1</sub>Fe<sub>10</sub>CoTi compound from Nd<sub>2</sub>O<sub>3</sub>, Fe<sub>2</sub>O<sub>3</sub>, Co and TiO<sub>2</sub>. High-energy-milled powders were heat treated at 1000 °C for 10 min to obtain the ThMn<sub>12</sub>-type structure. Volume fraction of the 1:12 phase was found to be as high as 95.7% with 4.3% of a bcc phase also present. The nitrogenation process of the sample was carried out at 350 °C during 3, 6, 9 and 12 h using a static pressure of 80 kPa of N<sub>2</sub>. The magnetic properties M<sub>r</sub>, µ<sub>0</sub>H<sub>c</sub>, and (BH)<sub>max</sub> were enhanced after nitrogenation, despite finding some residual nitrogen-free 1:12 phase. The magnetic values of a nitrogenated sample after 3 h were M<sub>r</sub> = 75 Am<sup>2</sup> kg<sup>–1</sup>, µ<sub>0</sub>H<sub>c</sub> = 0.500 T and (BH)<sub>max</sub> = 58 kJ·m<sup>–3</sup>. Samples were aligned under an applied field of 2 T after washing and were measured in a direction parallel to the applied field. The best value of (BH)<sub>max</sub> ~ 114 kJ·m<sup>–3</sup> was obtained for 3 h and the highest µ<sub>0</sub>H<sub>c</sub> = 0.518 T for 6 h nitrogenation. SEM characterization revealed that the particles have a mean particle size around 360 nm and a rounded shape.
|
|---|