Inhibition of Chloride Induced Crevice Corrosion in Alloy 22 by Fluoride Ions
Alloy 22 (N06022) is highly resistant to localized corrosion. Alloy 22 may be susceptible to crevice corrosion in pure chloride (Cl{sup -}) solutions under aggressive environmental conditions. The effect of the fluoride (F{sup -}) over the crevice corrosion induced by chloride ions is still not well established. The objective of the present work was to explore the crevice corrosion resistance of this alloy to different mixtures of fluorides and chlorides. Cyclic potentiodynamic polarization (CPP) tests were conducted in deaerated aqueous solutions of pure halide ions and also in different mixtures of chloride and fluoride at 90 C and pH 6. The range of chloride concentration [Cl{sup -}] was 0.001 M {le} [Cl{sup -}] {le} 1 M and the range of molar fluoride to chloride ratio [F{sup -}]/[Cl{sup -}] was 0.1 {le} [F{sup -}]/[Cl{sup -}] {le} 10. Results showed that Alloy 22 was susceptible to crevice corrosion in all the pure chloride solutions but not in the pure fluoride solutions. Fluoride ions showed an inhibitor behavior only in mixtures with a molar ratio [F{sup -}]/[Cl{sup -}] > 2. For mixtures with a molar ratio [F{sup -}]/[Cl{sup -}] of 7 and 10 the inhibition of crevice corrosion was complete.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 881887
- Report Number(s):
- UCRL-PROC-216071; TRN: US200613%%175
- Resource Relation:
- Conference: Presented at: Corrosion/2006 Conference and Exposition, San Diego, CA, United States, Mar 12 - Mar 16, 2006
- Country of Publication:
- United States
- Language:
- English
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