Nanocrystallization in Co67Cr7Fe4Si8B14 Amorphous Alloy Ribbons

The nanocrystallization of Co67Fe4Cr7Si8B14 amorphous ribbons which prepared by planar flow melt spinning process (PFMS) was investigated. Crystallization of the ribbons was studied by differential thermal analysis (DTA), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The DTA result of amorphous ribbon at heating rate of 10?C/min showed occurrence of phase transitions in two stages. The ribbons were isothermally annealed for 30 minutes in argon atmosphere at different temperatures between 300 and 650?C with 25?C steps. The magnetic properties of annealed samples were measured using a vibrating sample magnetometer (VSM). The VSM results revealed that optimum soft magnetic properties occurred at 400?C. XRD patterns showed that the samples isothermally annealed up to 450?C were amorphous, while TEM results at 400?C indicated 7-8 nm mean size nanocrytallites in amorphous matrix and size of the nanocrystallites increased by increasing temperature. Also by X-ray diffraction pattern, precipitation of different phases at higher temperatures confirmed.