Kinetics and influence of thermally induced crystallization of Fe,Ni-containing phases on thermomagnetic properties of Fe 40 Ni 40 B 12 Si 8 amorphous alloy

Thermal treatment of Fe 40 Ni 40 B 12 Si 8 amorphous alloy leads to crystallization of various Fe and Ni-containing phases and their recrystallization, affecting the functional properties of the alloy. Kinetics of multistep crystallization of Fe 40 Ni 40 B 12 Si 8 amorphous alloy and influence of thermally induced microstructural transformations on magnetic moment of the alloy were studied by means of structural examination, thermal analysis and thermomagnetic measurements. Temperature regions of growth and loss of magnetic moment of the alloy were correlated with the microstructural changes. Curie temperatures of the alloy in fully amorphous and fully crystallized form were observed at 620 and 910 K, respectively. Detailed kinetic study including deconvolution of the complex exothermic DTA peaks yielded Arrhenius parameters and kinetic model of individual crystallization steps, which reflect the nature of the studied processes and the alloy chemical composition. The obtained parameters and kinetic models can be used for kinetic predictions of thermal stability and functionality of the alloy.