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Electrochemical corrosion and film analysis studies of Fe and Fe- 18Cr in 1N H2SO4.

Authors
Driscoll-TJ; Covino-BS Jr.; Rosen-M
Source
Avondale, MD: U.S. Department of the Interior, Bureau of Mines, RI 8378, 1979 Jan; :1-33
Link
NIOSHTIC No.
10007964
Abstract
The electrochemical polarization behavior of Fe and Fe-18Cr has been characterized in rigorously controlled 1N H2SO4 solutions stirred with oxygen or an inert gas. Samples that underwent various levels of corrosion or passivation were examined using auger electron spectroscopy (aes) and ion sputtering. Passivation of iron occurred at a potential of approximately 0.6 Volt (1) in poorly stirred, oxygen-saturated solutions for forward polarization (scanning from cathodic to anodic potentials); (2) in ph-adjusted (increased), well-stirred, oxygen-saturated solutions for forward polarization; and (3) in well- and poorly stirred, oxygen- and helium-saturated solutions for reverse polarization. Passivation of Fe-18Cr occurred at a potential of approximately -0.1 Volt in helium-, nitrogen-, and oxygen-saturated solutions for all cases of forward polarization and most cases of reverse polarization. Elemental depth profiles indicated that films or adsorbed species were present on iron samples in solution subjected to open-circuit, active, and transpassive corrosion, cathodic reduction, and passivation. This conclusion was reached by considering the distribution of the solution species, primarily sulfur, in the films. Sulfur was present throughout the films on actively corroding samples, in the outer regions of films of passive and transpassive samples, and on the film surfaces of open-circuit and cathodically reduced samples.
Publication Date
19790101
Document Type
IH; Report of Investigations
Fiscal Year
1979
NTIS Accession No.
PB80-122716
NTIS Price
A04
Identifying No.
RI-8378
NIOSH Division
AVRC
Source Name
Avondale, MD: U.S. Department of the Interior, Bureau of Mines, RI 8378
State
MD
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