メスバウアー効果からみたFe-B-Si系非晶質合金の構造と結晶化挙動の組成依存性

抄録

Fe_90−xB_xSi₁₀ amorphous alloys containing 10∼17 at%B were studied by ⁵⁷Fe Mössbauer spectroscopy. The internal magnetic field distribution which was derived from the observed spectrum by a Fourier analysis was approximated by a sum of three Gaussian lines with the average internal fields of about 15.9 MA/m (component A), 19.9 MA/m (component B) and 23.9 MA/m (component C). With increasing boron content, the component A increases and the component C decreases. The intensity of the component A sharply increases from the composition of about 13 at% boron which is slightly higher than the eutectic composition. The component B increases to a maximum at about 13 at% boron and then decreases at higher boron contents. The compositional dependence of the fraction and the average internal field of each structural component suggests that the components A and B have Fe₂B-like and Fe₃B-like short range orders, respectively, and the component C has a lower boron content and a relatively high Si content of about 9 at%. The results of DSC and Mössbauer effect measurements on annealing Fe₈₀B₁₀Si₁₀ and Fe₇₆B₁₄Si₁₀ amorphous alloys suggest that the nucleations of the Fe₂B intermatallic compound and the α-Fe(Si) solid solution take place in the regions of components A and C, respectively.