Evaluation of compositional homogeneity of Fe-Co alloy nanoparticles prepared by thermal plasma synthesis

Abstract We successfully prepared nanosized Fe-Co alloy powder directly by a thermal plasma process, although a small amount of unprocessed Co was observed in the X-ray diffraction results. The mean particle size was ∼90 nm. The processed alloy particles were found to be single crystals, as confirmed by EBSD measurement. When an initial mixed powder having an Fe: Co ratio of 70 : 30 was used as the starting material, the mean and standard deviation of the Co concentration were 26.7 at% and 3.0 at%, respectively. The saturation magnetization values were in agreement with the bulk value, indicating that this small amount of oxygen dose not greatly affect the value of mass magnetization. This research realized the first full magnetization of a bare FeCo nanosized powder without any reduction treatment.