本研究主要是以電化學量測方法，探討硫代硫酸根離子(O.OOlM-O.2M)對鎳墓的0合金於lw的氧化銷水溶液中之孔蝕性質的影響。 由實驗結果顯示;鎳基690合金在硫代硫酸銷水溶被中，並無孔蝕現象發生。但在lwt%NaCI水溶液中，隨著硫代硫酸根離子的添加，則會降低其孔蝕起始電位值(Enp) ，但當添加的硫代硫酸納濃度超過某一臨界值時，其Enp值有再上升的趨勢;且當硫代硫酸納濃度超過O.lM時，就會有抑制孔蝕的效果發生。 此外，經SEM觀察及EDS分析蝕孔得知，硫代硫酸根離子的添加會使得蝕孔平均深度增加，同時在蝕孔內部並發現有硫元素的存在。這顯示硫代硫酸根離子對於孔蝕的成長扮演重要角色。

Effect of S20/' on pitting corrosion of Alloy 690 in 1 wt% NaCI solution was investigated using cyclic potentiodynamic polarization technique. The results showed that no pit was observed on Alloy 690 in the plain S20/·(O.00l-0.IM) solution. The presence of S20/"(�0. 0lM)in 1 wt% NaCl solution leaded to a decrease in the pit nucleation potential (Enp)of Alloy 690 as compared with that without S20/' addition. However， there existed a minimum concentration of S20/" beyond which Enp increased with increasing the concentration of S2032- in NaCI solution. Furthermore， pitting corrosion was inhibited as the S20/' concentration reaching O.lM. SEM micrographs showed that the pit depth increased with increasing S2032- concentration in 1 wt% NaCI solution. EDS analysis also revealed the presence of sulfur within the pits. These results demonstrated that S20/' played an important role in pitting corrosion growth process of Alloy 690 in 1 wt% NaCl solution.