Li B, Lang Y, Chen H, Feng H, Qu H, Sun X, Tian Z. Combined role of molybdenum and nitrogen in Limiting corrosion and pitting of super austenitic stainless steel.
Heliyon 2024;
10:e25964. [PMID:
38375291 PMCID:
PMC10875432 DOI:
10.1016/j.heliyon.2024.e25964]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 02/05/2024] [Accepted: 02/06/2024] [Indexed: 02/21/2024] Open
Abstract
The molybdenum and nitrogen content of super austenitic stainless steel in Cl- solution is shown to influence pitting resistance using immersion, electrochemical testing, and simulation. Variations in Mo and N content affect the defect density, resistance, and densification of the passive film, thereby reducing the number of pitting. A higher local pH associated with the pitting pits and an increase in NH3(NH4+) are the results of increased N content, which also slows the rate of pitting expansion. The combined effects of fewer actively reactive spots within the passive film retarded pitting, and decreased corrosion rates due to NH3(NH4+) mitigation of local acidity which serves to reduce the corrosion rate. The work function is improved to a greater extent when Mo and N are co-doped compared with individual Mo and N doping, and the adsorption energy is significantly increased when Mo and N are co-doped, indicating a synergistic role for Mo and N in the prevention of corrosion by Cl-.
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