Co-Fe-Ni-B-Si-Cr based amorphous strips containing nitrogen were manufactured via melt spinning, and then devitrified by crystallization treatment at the various annealing temperatures of for up to 30 minutes in an inert gas atmosphere. The microstructures were examined by using XRD and TEM and the magnetic properties were measured by using VSM and B-H meter. Among the alloys, the amorphous ribbons of containing 121 ppm of nitrogen showed relatively high saturation magnetization. The alloy ribbons crystallized at showed that the grain size of alloy containing 121 ppm of nitrogen was about f nm, which exhibited paramagnetic behavior. The formation of nano-grain structure was attributed to the finely dispersed Fe4N particles and the solid-solutionized nitrogen atoms in the matrix. Accordingly, it can be concluded that the nano-grain structure of 5nm in size could reduce the core loss within the normally applied magnetic field of 300A/m at 10kHz.

This study investigated a mechanism for controlling the shape of Cu nanocrystals fabricated using the polyol process, which considers the thermodynamic transition from a facetted surface to a rough surface and the growth mechanisms of nanocrystals with facetted or rough surfaces. The facetted surfaces were stable at relatively low temperatures due to the low entropy of perfectly facetted surfaces. Nanocrystals fabricated using a coordinative surfactant stabilized the facetted surface at a higher temperature than those fabricated using a non-coordinative surfactant. The growth rate of the surface under a given driving force was dependent on the surface structure, i.e., facetted or rough, and the growth of a facetted surface was a thermally activated process. Surface twins decreased the activation energy for growth of the facetted surface and resulted in rod- or wire-shaped nanocrystals