EFFECT OF HEAT FLUX ON THE CORROSION OF ALUMINUM BY WATER. PART II. INFLUENCE OF WATER TEMPERATURE, VELOCITY, AND pH ON CORROSION-PRODUCT FORMATION
S>The influence of water temperature, pB, and velocity on corrosion and on corrosion-product formation on the surface of aluminum alloys subjected te a very high heat flux was detemnined. At a heat flux of 1.5 x 10/sup 6/ Btu/hr-ft/ sup 2/ and with cooling-water temperatures and velocities in the ranges of 131 to 223 deg F and 32 te 48 fps, respectively, a tightly adherent layer of corrosion products ( alpha Al/sub 2/O/sub 3/ - H/sub 2/O) formed on the surface of the aluminum specimens at a linear rate during 10-day tests. The rate at which the corrosion product formed (and the rate of temperature increase in the aluminum) was markedly influenced by the pH of the coolant. With high-purity water as the coolant, oxide films as thick as 1.5 to 2.0 mils formed in 10 days. When the pH of the cooling water was adjusted to 5 with nitric acid, oxide films less than 0.5 mil formed under the same conditions. From measured oxide thicknesses and temperature drops across the corrosion-product films, a thermal conductivity of 1 Btu/hr- ft/sup 2/- deg F/ft was calculated for the aluminum oxide film. The rate of oxide formation was independent of the alloy and the velocity in the range investigated The temperature of the cooling water was a significant factor; the lower the water temperature, the slower the rate of film formation Because of the manner in which the specimens were fabricated, quantitative corrosion measurements were not possible. However, it was qualitatively established that corrosion was not severe; and, except in one case, evidence of localized attack was not found. It was concluded that under the conditions expected to exist during operation of the High-Flux Isotope Reacter, aluminum would be a suitable material for cladding fuel elements. (auth)
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- DOE Contract Number:
- W-7405-ENG-26
- NSA Number:
- NSA-15-011524
- OSTI ID:
- 4084602
- Report Number(s):
- ORNL-3056
- Resource Relation:
- Other Information: Orig. Receipt Date: 31-DEC-61
- Country of Publication:
- United States
- Language:
- English
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