Fe72B22Y6塊狀非晶合金在600~700℃空氣下之氧化行為

Oxidation Behavior of an Fe72B22Y6 Bulk Metallic Glass in Air at 600 ~ 700 ℃

本研究探討鐵基塊狀非晶合金Fe72B22Y6及其結晶材料X-Fe72B22Y6在空氣下600 ~ 700℃之氧化行為。研究顯示，兩種合金之氧化動力學皆遵守拋物線型定律，唯非晶合金在700℃時呈現㆔段式之動力學行為；此外，兩種合金之氧化速率常數皆隨溫度升高而加快，而非晶合金之氧化速率較結晶合金慢約20倍。非晶合金氧化後生成的氧化物主要為B2O3及少量的Fe3O4與FeO，而晶質合金之氧化物分為內、外兩層，其中，外層主要為Fe2O3，內層為Fe3O4和YBO3；生成B2O3是非晶合金氧化速率較慢的主因。

The oxidation behavior of an Fe72B22Y6 bulk glassy alloy and its crystalline counterpart was studied over the temperature range 600 ~ 700 ℃ in dry air. The oxidation kinetics of both glassy and crystalline alloys generally followed the parabolic rate law although three-stage kinetics was noted at 700℃ for the glassy alloy. The oxidation rates of the two alloys increased with increasing temperature, and the parabolic rate constants of the glassy alloy are much lower than those of the crystalline counterpart. The scales formed on the glassy alloy consisted mainly of boron oxide (B2O3) and minor amounts of iron oxides (Fe3O4/FeO). Conversely, duplex scales formed on the crystalline counterpart were composed of an outer layer of Fe2O3 and an inner layer of Fe3O4 and YBO3. The formation of B2O3 is responsible for the reduced oxidation rates of the glassy alloy as compared to those of crystalline counterpart.