Passivity and breakdown of carbon steel in organic solvent mixtures of propylene carbonate and dimethoxyethane
- Naval Surface Warfare Center, West Bethesda, MD (United States). Carderock Div.
- Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Materials Science and Engineering
- Naval Academy, Annapolis, MD (United States). Dept. of Mechanical Engineering
The passivity and breakdown of passivity of 1018 carbon steel in propylene carbonate (PC) and 1,2-dimethoxyethane (DME) mixtures with 0.5 molar lithium hexafluoroarsenate supporting electrolyte were examined via several electrochemical and surface analytical methods. The PC-DME/0.5 M LiAsF{sub 6} mixtures ranged from 10 to 90 mol % PC. The results from the PC/DME mixtures were compared to passivating mechanisms found in pure PC and DME solutions. In PC-rich mixtures, the breakdown of passivity occurred near the oxidation potentials of either organic solvent. Premature breakdown of the carbon steel in PC-DME mixtures occurred at sulfide inclusions as was observed earlier in PC/0.5 M LiAsF{sub 6} solutions although passive films attempted to form at these inclusion sites in mixtures containing at least 10 mol % DME. As the DME content increased in the PC-DME mixtures, the passive films formed on bare steel surfaces possessed an increasing polymer film character. In 50 and 70 mol % DME solutions nonprotective polymer films were formed. The nonprotective nature of these films indicated that PC passivation mechanisms competed and interfered with the DME mechanism of electropolymerized film formation. Only in 10 mol % PC-90 mol % DME mixtures were protective electropolymerized films formed on 1018 carbon steel.
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 653385
- Journal Information:
- Journal of the Electrochemical Society, Vol. 145, Issue 7; Other Information: DN: Paper presented at the Meeting of the Electrochemical Society, August 31--September 5, 1998, Paris (FR); PBD: Jul 1998
- Country of Publication:
- United States
- Language:
- English
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