Terms and results of hydrogen permeation testing of oxide-scaled high-temperature alloys

Journal Article · Sat Sep 01 04:00:00 EDT 1984 · Nucl. Technol.; (United States)

OSTI ID:6026062

Schaefer, J; Hecker, R; Stover, D

The phenomenon of hydrogen permeation through high-temperature alloys has been recognized as an important problem in developing nuclear energy production systems. Investigations are concerned with experimental techniques and requirements to conform with the concept of practical development. After establishing the data of hydrogen permeation through bare alloys, efforts are directed toward investigating the permeation behavior of surface oxidized walls. In this way 12 alloy types are examined under various conditions. The reduced penetration occurring under ''process gas'' atmosphere is determined by the ''impeding factor'': It is the ratio of permeation rates measured under special conditions in the case of bare alloy annealed in pure hydrogen and in the case of its oxidized surface. One influence on the permeation behavior is proceeding from the metallic substrate of oxide coating: Centricast and wrought types of alloys are effective in different ways. Varied treatment before coating was significant only in the case of annealing in hydrogen. Most influential is the temperature acting upon both the permeating and the coating quality in a compensating manner. Temperature cycling in oxidizing atmosphere points to improved impeding. The relationship between the oxidation potential and the impeding conditions is not yet clear. In the temperature range between 650 and 900/sup 0/C, a square root behavior below about5-bar hydrogen pressure is dominant, whereas a linear pressure dependence was detected above. A crossover range is obvious, especially distinct at higher temperatures. The influence of chromium oxide in the corrosion cover is manifested by metallurgical postexamination results corresponding with permeation data of selected samples.

• Research Organization: Kernforschungsanlage Julich GmbH Institut fur Reaktorentwicklung, D-5170, Julich
• OSTI ID: 6026062
• Journal Information: Nucl. Technol.; (United States), Journal Name: Nucl. Technol.; (United States) Vol. 66:2; ISSN NUTYB
• Country of Publication: United States
• Language: English

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ALLOYS
ANNEALING
CHALCOGENIDES
CHEMICAL REACTIONS
CHROMIUM COMPOUNDS
CHROMIUM OXIDES
COATINGS
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METALLURGICAL EFFECTS
NONMETALS
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OXIDES
OXYGEN COMPOUNDS
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PRESSURE DEPENDENCE
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REACTOR MATERIALS
REACTORS
SCALING
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