Influence of low-temperature annealing on the morphology of the surface layer of an iron-based amorphous alloy

摘要

The influence of isothermal annealing on the chemical composition, microstructure, and surface relief of ribbons of an amorphous Fe77NiSi9B13 alloy was studied using Auger electron spectroscopy and transmission electron, atomic-force, and scanning tunneling microscopy. It is established that an annealing below the glass transition temperature results in a boron enrichment of the ribbon surface layer on the side of the ribbon that was not in contact with the roller during quenching. On both sides of a ribbon, islands of crystallized material 2-5 mu m in size appear consisting of nano- and microcrystals of alpha-Fe on the roller-contacting side and of iron boride on the opposite side. The surface relief on the roller-contacting side of a ribbon and that on the opposite side are shown to differ in terms of their spectral and fractal characteristics after annealing. The effect of the chemical composition and excess free volume of the surface layer on the formation of islands of crystallized material and surface relief is discussed.