本研究主要探討氯離子濃度及溫度對2101雙相不銹鋼孔蝕性質的影響。實驗材料使用2101雙相不銹鋼，並在1100 °C下進行固溶均質化熱處理，而後藉由循環極化試驗評估2101雙相不銹鋼之孔蝕敏感性隨環境條件不同的變化。並且透過定電位鈍化處理去釐清不同溫度下，鈍化膜之化學組成的差異，進一步說明其對於孔蝕抵抗性的影響。此外以2205雙相不銹鋼作為實驗對照組，藉此探討合金含量在孔蝕性質中所扮演的角色。
電化學實驗結果顯示，在所有環境條件下，2205雙相不銹鋼之抗蝕性質皆優於2101雙相不銹鋼。在不同氯離子濃度之NaCl水溶液中，2101雙相不銹鋼之孔蝕性質以在21300 ppm氯離子濃度中受溫度變化的影響最為顯著，當 10 °C升溫至25 °C時，表面開始有孔蝕生成；而2205雙相不銹鋼之孔蝕性質同樣以在21300 ppm氯離子濃度中受溫度變化的影響最為顯著，但卻於50 °C下才開始發生孔蝕。另一方面在不同溫度下，2101雙相不銹鋼之Enp值在25 °C下受氯離子濃度變化的影響最為顯著，而2205雙相不銹鋼之Enp值則是在50 °C下受氯離子濃度變化的影響最為顯著，且兩者之Enp驟降的氯離子濃度區間皆為250 ppm至2500 ppm。此外孔蝕皆優先發生於2101及2205雙相不銹鋼中的α相，並隨著溫度上升，孔蝕將由點狀轉為蕾絲狀的腐蝕形貌，而當表面蕾絲覆蓋層進一步受到溶解後，最終則會留下碗狀的蝕孔。
XPS分析結果顯示，兩種雙相不銹鋼之O1s複合峰中氧化層的含量比例皆隨溫度上升而增加，其中氧化層含量比例的增加是由2101雙相不銹鋼中的Fe2O3所貢獻，而2205雙相不銹鋼則是Cr2O3。此外兩種雙相不銹鋼之N1s的化學態主要以NH3存在，且其含量比例以2101雙相不銹鋼較高，而這可能與2101雙相不銹鋼具有較高的N含量有關。藉此可以進一步證實Mo與N之間的協同作用，主要由於2101雙相不銹鋼具有的Mo含量較低，因此無法藉由增加N含量來提升抗孔蝕性質，而有較高的孔蝕敏感性。

The corrosion behavior of 2101 duplex stainless steel (DSS) in NaCl solution was studied and compared with that of 2205 DSS. The effects of chloride concentration and solution temperature on pitting corrosion behavior were focused. The relative sensitivity to pitting corrosion of the constituent phases in both 2101 and 2205 DSSs was also explored. Pitting corrosion susceptibility was evaluated by conducting cyclic polarization curve measurement. The corrosion morphology was examined by a scanning electron microscope (SEM), while the corrosion product and the passive film were analyzed by using energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The experimental results showed that the pitting corrosion resistance of 2101 DSS was inferior to that of 2205 DSS by exhibiting a lower threshold chloride concentration and a lower critical pitting temperature. For both 2101 and 2205 DSSs, the ferrite phase was more susceptible than austenite phase to pitting corrosion.

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