การสร้างแผนภูมิพอร์เบซ์สำหรับเหล็กกล้าไร้สนิม 316L ในสารละลายที่มีคลอไรด์ผสมด้วยเทคนิคทางไฟฟ้าเคมี / ประทีป วงศ์บัณฑิต = Construction of Pourbaix diagrams for the 316L stainless steel in aqueous solution containing chloride by an electrochemical technique / Pratip Vongbandit
This research studied the effects of chloride concentrations of 0, 50, 500 and 5,000 ppm in the solution saturated with oxygen from air at the pH 2, 4, 6, 8, 10 and 12 at temperature of 25℃ on the corrosion behaviors of the AISI 316L stainless steel by using an electrochemical technique. The Pourbaix diagrams were constructed from the electrochemical data. Increasing of chloride concentration in the solution saturated with oxygen form air has no effects on the corrosion and primary passivation potentials. However, transpassive and protection potentials of the AISI 316L stainless steel decreases with increasing amount of chloride. The results reflect in the Pourbaix diagram that the passivity areas include perfect passivity and imperfect passivity areas are smaller when the chloride concentration increase, but no significant change in the immunity and general corrosion areas. Chloride in acidic solution has more influence on the change of areas in the Pourbaix diagram more than chloride in basic solution. Possible dissolved ions in general corrosion and pitting corrosion areas were analyzed. Only ferric ion (Fe3+) was detected เท general corrosion area. In the pitting corrosion area, ferrous ion (Fe2+), ferric ion (Fe3+), chromic ion (Cr3+)1 nikelous ion (Ni2+) and molybdate ion (MoO4 2-) were detected.