本研究探討2205 雙相不銹鋼經由包覆擴散製程 (Pack cementation) 進行表面滲矽處理，以掃描式電子顯微鏡觀察滲矽後組織變化及分析兩相之矽化梯度差異，並對表面矽化後之雙相不銹鋼進行極化曲線測試，分析其耐蝕影響。試驗結果矽元素在雙相不銹鋼中的肥粒體（α相）與沃斯田體（γ相）中有顯著不同的固溶及擴散行為，且當表面矽固溶量大於3%時，雙相組織消失而形成單一α相。而從能量散佈能譜 (EDS) 發現在α及γ相中的擴散深度和濃度梯度有明顯差異，滲矽量α相較γ相高且深度較深，矽化處理後雙相區中γ/α體積分率大幅上升至74/26。
經過矽化處理且研磨至雙相組織後之試片，其表面矽含量約1.0%，並分別在1M氯化鈉、1M鹽酸及1M硫酸溶液下進行動電位極化曲線測試。在鹽酸溶液下進行動電位極化曲線顯示鈍態區範圍縮小；在氯化鈉及硫酸溶液下進行動電位極化曲線皆能維持寬廣鈍化區。

The purpose of this study is to explore the effect of siliconization on microstructure and corrosion resistance of 2205 duplex stainless steel. Siliconization was achieved by pack cementation. The microstructure and Si concentration of siliconized 2205 DSS were analyzed by a scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS), respectively. Corrosion behavior was evaluated by polarization curve measurement. The experimental results showed that the Si solubility and diffusion behavior between austenite and ferrite were quite different. Duel phases transformed single phase as the Si concentration increases to 3%. The concentration and diffusion depth of α phase were more than γ phase. The passive region of siliconized 2205 DSS under 1M HCl solution were narrowed after polarization curve. The passive region of siliconized 2205 DSS under 1M NaCl and 1M H2SO4 solutions remained broad after polarization curve.

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