Application of the Polarised Potential-pH Diagrams to Investigate the Role of Sulfate and Dissolved Oxygen in the 3550-ppm NaCl Solution on the Corrosion Behaviour of AISI 316L Stainless Steel원문보기
Chandra-ambhorn, S.
(Department of Production Technology, The Sirindhorn International Thai-German Graduate School of Engineering (TGGS), King Mongkut’s Institute of Technology North Bangkok (KMITNB))
,
Kumpai, K.
(Corrosion Technology Department, Thai-French Innovation Centre, The Sirindhorn International Thai-German Graduate School of Engineering (TGGS), King Mongkut's Institute of Technology North Bangkok (KMITNB))
,
Muangtong, P.
(Department of Production Technology, The Sirindhorn International Thai-German Graduate School of Engineering (TGGS), King Mongkut's Institute of Technology North Bangkok (KMITNB))
,
Wachirasiri, W.
(Materials and Metallurgical Engineering Program, The Sirindhorn International Thai-German Graduate School of Engineering (TGGS), King Mongkut’s Institute of Technology North Bangkok (KMITNB))
,
Daopiset, S.
(Department of Production Engineering, Faculty of Engineering, The Sirindhorn International Thai-German Graduate School of Engineering (TGGS), King Mongkut’s Institute of Technology North Bangkok (KMITNB))
The cyclic polarisation technique was applied to determine the corrosion, primary-passivation, transpassive, and protection potential of AISI 316L stainless steels immersed in 3550-ppm NaCl solution containing sulfate in the content up to 3000 ppm. The solutions were kept constant at $27^{\circ...
The cyclic polarisation technique was applied to determine the corrosion, primary-passivation, transpassive, and protection potential of AISI 316L stainless steels immersed in 3550-ppm NaCl solution containing sulfate in the content up to 3000 ppm. The solutions were kept constant at $27^{\circ}C$ and saturated by laboratory air. The solution pH was varied from 3 to 11. Each type of potentials was plotted in function of pH and linked as lines to determine the different zones in the constructed potential-pH diagram. The predominant regimes of the immunity, general corrosion, perfect passivation, imperfect passivation, and pitting corrosion were determined based on those lines of potentials. Comparing to the potential-pH diagram of specimens immersed in the aerated and deaerated 3550-ppm NaCl solutions, the addition of 3000-ppm $Na_2SO_4$ to these solutions increased the overall, perfect and imperfect, passivation regime by shifting the transpassive-potential line to the noble direction. However, it also widened the imperfect passivation area. The addition of $Na_2SO_4$ did not significantly affect the corrosion potential. It was found that the dissolved oxygen tends to negatively shift the transpassive-potential and protection-potential lines at all studied pH. The considerable effect of dissolved oxygen on corrosion and primary-passivation potentials could not be observed.
The cyclic polarisation technique was applied to determine the corrosion, primary-passivation, transpassive, and protection potential of AISI 316L stainless steels immersed in 3550-ppm NaCl solution containing sulfate in the content up to 3000 ppm. The solutions were kept constant at $27^{\circ}C$ and saturated by laboratory air. The solution pH was varied from 3 to 11. Each type of potentials was plotted in function of pH and linked as lines to determine the different zones in the constructed potential-pH diagram. The predominant regimes of the immunity, general corrosion, perfect passivation, imperfect passivation, and pitting corrosion were determined based on those lines of potentials. Comparing to the potential-pH diagram of specimens immersed in the aerated and deaerated 3550-ppm NaCl solutions, the addition of 3000-ppm $Na_2SO_4$ to these solutions increased the overall, perfect and imperfect, passivation regime by shifting the transpassive-potential line to the noble direction. However, it also widened the imperfect passivation area. The addition of $Na_2SO_4$ did not significantly affect the corrosion potential. It was found that the dissolved oxygen tends to negatively shift the transpassive-potential and protection-potential lines at all studied pH. The considerable effect of dissolved oxygen on corrosion and primary-passivation potentials could not be observed.
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제안 방법
Not only the effect of dissolved ions, the dissolved gases in solution especially oxygen from air also play the role on the corrosion behaviour of the alloy contacted with solution. The objectives of this work are then to investigate the role of dissolved ions, particularly the sulfate one in chloride-containing aqueous solution, and dissolved oxygen on the corrosion behaviour of stainless steels. The cyclic polarisation method is primarily performed in order to obtain data to construct the potential-pH diagram.
대상 데이터
A material used in this experiment was an AISI 316L stainless steel. The chemical composition is given in Table 1.
1 mV/sec. Reference and counter electrodes were Ag/AgCl and platinum respectively. The cyclic polarisation curves illustrating the polarized potential as a function of current density were obtained.
이론/모형
The cyclic potentiodynamic experiment was carried out using potentionstat model 352/252. The scan rate was 0.
참고문헌 (7)
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