抄録
Amorphous and crystallized Fe78Si9B13 alloys were oxidized in a 20%O2–Ar gas stream at the temperatures of 623 to 973 K for 70 to 80 ks. The mass change of the sample was continuously measured during the oxidation. The oxidation products formed on the sample surface were examined with using XRD, SEM, EPMA, ESCA and SIMS. The mass gain of the amorphous sample during the oxidation at 673 K for 72 ks was higher than that of the crystallized alloy. The thin oxide film formed on the amorphous and crystallized samples were about 13 and 8 nm, respectively.
SIMS profile revealed that the thin oxide was mainly composed of Fe-oxides and SiO2 in the outer and inner portions, respectively. Nodular oxides which were composed of Fe2O3, Fe3O4, SiO2 and B2O3 were also formed on the amorphous sample. As the temperature was raised, the number and size of the nodular oxides increased, and the oxide formed at 973 K was composed of Fe-oxides, SiO2 and B2O3. The oxidation rate of the alloy was much lower than the pure Fe due to the formation of the thin oxide film containing SiO2.
