UNS S44400不銹鋼在不同氧分壓下之高溫氧化行為

High-Temperature Oxidation of UNS S44400 Stainless Steel at Various Oxygen Atmospheres

本論文探討UNS S44400不銹鋼在850 ~ 950℃不同氧分壓下（Po2 = 0.01 ~ 1 atm）的氧化行為。整體而言，合金之氧化動力學皆遵守抛線律，且氧化速率會隨溫度上升而加快；但氧化速率不隨氧分壓增加而增加，顯示合金氧化後的氧化生成物呈現N型半導體的特徵。由顯微結構分析得知，合金氧化的主要生成物以Cr2O3為主，並有少量Mn1.5Cr1.5O4及MnCr2O4生成；而在氧化層次表面的基材中亦有少量的TiO內氧化粒子生成；此外，在900℃以上氧化時更有少量的TiO2在表面生成。

The oxidation behavior of UNS S44400 Stainless Steel (444SS) was studied over a temperature range of 850 ~ 950 ℃ at various oxygen-containing atmospheres (at Po2 = 0.01 ~ 1 atm). The oxidation kinetics of the alloys followed the parabolic-rate law in all cases and the oxidation rate constants (kp values) increased with increasing temperature. It was found that the kp values of the alloy were independent of oxygen pressure, indicating that the scaling behavior of the alloy exhibited an N-type semiconductor property. Based on microstructural analyses, the scales formed on the 444SS consisted mostly of Cr2O3, minor amounts of Mn1.5Cr1.5O4 and MnCr2O4, and TiO particles generated by internal oxidation. In addition, a small amount of TiO2 was also observed on the surface of scales at T ≥ 900 ℃.