Air Oxidation of an Fe{sub}48Cr{sub}15C{sub}15Mo{sub}14B{sub}6Er{sub}2 Bulk Metallic Glass at 600-725℃

摘要

The oxidation behavior of an Fe{sub}48Cr{sub}15C{sub}15Mo{sub}14B{sub}6Er{sub}2 bulk metallic glass (Fe-BMG) was studied over the temperature range of 600-725℃ in dry air. The oxidation kinetics of the glassy alloy followed a two-stage parabolic rate law at T ≤ 650℃, while the single-stage linear rate was observed at higher temperatures (T ≥ 675℃). The oxidation rates of the Fe-BMG at T ≤ 625℃ were much lower than those of the commercial 304 stainless steel (304 SS), revealing the excellent oxidation resistance of the amorphous alloy. A continuous, thin layer of chromium oxide (Cr{sub}2O{sub}3) containing some iron was formed at T ≤ 650℃, while typical hump iron oxides intermixed with minor amounts of Cr{sub}2O{sub}3 and MoO{sub}2 were observed at T ≥ 675℃. In addition, a substrate phase transformation from the amorphous structure to Fe-Cr and FeCrMo crystalline phases was detected after the oxidation. Very likely, the formation of the non-protective Fe{sub}3O{sub}4 and MoO{sub}2 breaks the scale integrity and allows the rapid cation/anion transportation, resulting in the fast linear-kinetics behavior of the Fe-BMG at T ≥ 675℃.