Impact of cobalt content on the crystallization pattern in the Finemet-type ribbons

In this paper, crystallization behavior of BCC iron phase in two Finemet-type ribbons with different cobalt content has been studied. Studied ribbons consist of 58.8 and 65 M percents of cobalt (Fe14.7Co58.8Cu1Nb3Si13.5B9 and Fe13.8Co65Cu0.6Nb2.6Si9B9). Identification of crystallized phase has been performed by means of X-ray diffraction and Neutron Diffraction. Kinetics parameters of this process have been obtained through the Differential Scanning Calorimetry measurements with different heating rates. The main aim of this work was to check the correlation between the kinetic parameters such as activation energy, rate constant and crystallization difficulty and the cobalt content in the studied ribbons. It was shown that the slight increase of cobalt amount leads to the significant change of activation energy from 300 to 250 kJ/mol.