The role of carbon dioxide in the atmospheric corrosion of zinc: A laboratory study
- Chalmers Univ. of Technology and Univ. of Goeteborg (Sweden). Dept. of Inorganic Chemistry
The authors report on a laboratory study of the atmospheric corrosion of zinc in air containing different concentrations of carbon dioxide (CO{sub 2}) (< 1,350, 1,000, and 40,000 ppm CO{sub 2}). The samples were exposed to synthetic atmospheres with careful control of CO{sub 2} concentration, sulfur dioxide (SO{sub 2}) concentration, relative humidity, and flow conditions. The relative humidity was 95%. Mass gain and metal loss results are reported. The corrosion products were analyzed quantitatively and qualitatively by a combination of grazing-angle x-ray diffraction, scanning electron microscopy, gravimetry, and quantitative analysis for carbonate. The corrosion rate of zinc increased with increasing CO{sub 2} concentration. In the presence of carbon dioxide Zn{sub 4}CO{sub 3}(OH){sub 6} {center_dot} H{sub 2}O formed. Hydrozincite, Zn{sub 5}(CO{sub 3}){sub 2}(OH){sub 6} was only identified after exposure to high CO{sub 2} concentration. Zinc hydroxycarbonate was converted into hydroxysulfate exposed to air containing 225 ppb SO{sub 2}. Zn{sub 4}SO{sub 4}(OH){sub 6} {center_dot} 4H{sub 2}O was produced in all exposures including SO{sub 2}. The zinc hydroxycarbonate surface film formed in the presence of CO{sub 2} was not protective in humid SO{sub 2} polluted air.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 599640
- Journal Information:
- Journal of the Electrochemical Society, Journal Name: Journal of the Electrochemical Society Journal Issue: 1 Vol. 145; ISSN 0013-4651; ISSN JESOAN
- Country of Publication:
- United States
- Language:
- English
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