水蒸氣對AISI 316不銹鋼高溫氧化性質影響研究

Effect of Water Vapor on the High Temperature Oxidation Behavior of AISI 316 Stainless Steel

本研究主要探討AISI 316不銹鋼在含水蒸氣氣氛下進行退火處理時之高溫氧化行為。在本研究中利用熱重分析儀（TGA）分析其高溫氧化速率，並利用SEM及XRD觀察銹皮型態及其結構。實驗結果顯示：在含水蒸氣之空氣中於1030℃時，316 SS之氧化速率值遠比在乾燥空氣氣氛中為高。在乾燥空氣中之退火時所生成的氧化銹皮僅有一層，而在潮濕空氣中所生成者，則呈多層複雜的組織；此多層結構的銹皮是以氧化物及富含鎳元素的金屬層交互累積而成。在潮濕空氣中退火時生成複雜結構銹皮的機制因溫度不同而有所區別，本文中將加以詳細討論。

The effect of water vapor on the high temperature oxidation during annealing of AISI 316 stainless steel was investigated. The oxidation kinetics was studied by employing thermalgravimetric analysis (TGA). The morphology, compositions and structures of the scale were also examined by using SEM and XRD. The experimental results showed that a substantial increase in the oxidation rate of the 316 SS at 1030℃ was observed if the steel was annealed in water vapor containing atmosphere as compared with that in dry air. A single layer of scale was observed on the surface of 316 SS when annealed in dry air. However, the composition and structure of the scale became rather complex when it was annealed in wet air. Multi-layer structure of scale composed of alternate layer of oxide and Ni-rich metallic phase were observed in the later case. Furthermore, two different oxidation mechanisms might involve in the scaling of 316 SS during annealing in wet air. The complex process for the formation of complicated scale structure is to be discussed.