Crystallization kinetics and soft magnetic properties in metalloid-free (Fe, Co)90Zr10 amorphous and nanocrystalline alloys

Abstract

Microstructure and magnetic properties of metalloid-free (Fe100−xCox)90Zr10 amorphous and nanocrystalline alloys were characterized. Devitrification of these amorphous alloys occurs in two overlapped transformations leading to the formation of α-Fe(Co) and Fe(Co)Zr2 phases. Constant local Avrami exponents have been found for each individual process. Although Co-free alloy shows a larger grain size, crystalline fractions are similar for both alloys after equivalent annealing. Good soft magnetic properties at room temperature have been observed for amorphous and nanocrystalline alloy with x=30, which exhibits an amorphous Curie temperature of 735K. The x=0 amorphous alloy is paramagnetic at room temperature and nanocrystalline samples exhibit a transition to superparamagnetic behavior.