Nanocrystallization of Fe₄₀Ni₃₈B₁₈Mo₄ metglass

The development of nanocrystalline Fe-Si-B-Nb-Cu alloys, (FINEMET), established a new approach to develop soft-magnetic materials with excellent soft magnetic properties: extremely low coercivities, high permeabilities, low energy losses, etc. This has triggered major interest and research activity in this area. This paper reports the evolution of microstructure as a function of annealing time and temperature. Microstructure has been characterized by using transmission electron microscope (TEM), X-Ray diffraction and positron annihilation spectroscopy. The kinetics of the crystallization process have been determined using differential scanning calorimeter. The aim of the present study is to develop an understanding of the origins of the microstructures and properties, in order to facilitate the design and development of new materials and also to characterize the stability of the materials to assess possible problems in applications