2101及2105雙相不鏽鋼於含氯離子水溶液中之孔蝕性質比較研究

Comparative Study on Pitting Corrosion Behaviors of 2010 and 2205 Duplex Stainless Steels

本研究探討2101和2205雙相不銹鋼在不同溫度及氯離子濃度的水溶液中的孔蝕敏感性，並比較其差異。利用動電位極化曲線來評估孔蝕敏感性，並以掃描式電子顯微鏡觀察孔蝕的形貌與微觀組織的關係。試驗結果顯示，兩種雙相不銹鋼的孔蝕電位皆隨著水溶液氯離子濃度及溫度的增加而降低；比較在恆溫下的孔蝕臨界氯離子濃度，以及在固定氯離子濃度下的臨界孔蝕溫度，2101雙相不銹鋼的孔蝕敏感性比2205雙相不銹鋼高。從試片表面腐蝕形貌的觀察，兩種雙相不銹鋼的孔蝕皆優先生成於肥粒體相（α相）。各組成相之化學成分與孔蝕敏感性的關係是本研究討論的重點。

The pitting corrosion behaviors of 2101 and 2205 duplex stainless steels (DSSs) in NaCl solutions with various concentration and at different temperature were studied and compared. Pitting corrosion susceptibility was evaluated by conducting cyclic polarization curve measurement. The corrosion morphology was examined by a scanning electron microscope (SEM). 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. The relative sensitivity to pitting corrosion of the constituent phases in both 2101 and 2205 DSSs was addressed in terms of their chemical composition.