HYDROGEN AND OXYGEN ISOTOPES APPLIED TO THE STUDY OF WATER-METAL REACTIONS. EXCHANGE OF D$sub 2$$O$$sup 18$ WITH ALPHA ALUMINA MONOHYDRATE

Technical Report · Fri Aug 01 00:00:00 EDT 1958

DOI:https://doi.org/10.2172/4324904· OSTI ID:4324904

Bernstein, R. B.

Isotopes of hydrogen and oxygen may be useful in elucidating the mechanism of aqueous corrosion reactions, in which an important step may be diffusion of protons and/or hydroxyl for oxide) ions through a thin protective film. The technique of isotope exchange and the kinetic isotope effect both appear applicable. For the reaction between water and aluminum, the product (above 90 deg C) is alpha -alumina monohydrate ( alpha -AlCDH). The exchange of D/sub 2/O/sup 18/ with alpha -AlOOH (sub-micron crystallite size) was examined from 100 to 230 deg C. The rate of D-H exchange was appreciable: O/sup 18 / exchange was slow. The O/sup 18/ content of the separate phases suggested that only half the O atoms in alpha -AlOOH are exchangeable. Results were interpreted on the basis of a slow step involving independent diffusion of protons and oxygen carrier ions. The activation energy for the proton diffusion coefficient was ~ 12 kcal. The isotope exchange technique was applied to the reaction between water and aluminum at 100 deg C. Al (type 1100) sheets reacted with H/sub 2/O to the ''protective film'' stage, then with D/sub 2/O. The D content of the film increased, but the net exchange (corrected for D uptake) was only slight. Impurities (Fe and Si) in the Al may enter into the alpha -AlOOH lattice and reduce proton mobility. Further corrosion-exchange studies with pure aluminum are needed to decide whether or not there exists a relationship between proton lability and corrosion rate. The D isotope effect on the rate of aqueous corrosion reactions should be useful in assessing the importance of proton mobility in the mechanism. (auth)

• Research Organization: Argonne National Lab., Lemont, Ill.
• DOE Contract Number: W-31-109-ENG-38
• NSA Number: NSA-12-015322
• OSTI ID: 4324904
• Report Number(s): ANL-5889
• Resource Relation: Other Information: Orig. Receipt Date: 31-DEC-58
• Country of Publication: United States
• Language: English

Related Subjects

CHEMISTRY
ALUMINUM
ALUMINUM HYDROXIDES
ALUMINUM OXIDES
CHEMICAL REACTIONS
CORROSION
CORROSION PROTECTION
DEUTERIUM
DIFFUSION
ENERGY
EXCITATION
FILMS
GRAIN SIZE
HEAVY WATER
HYDROGEN
HYDROXIDES
IMPURITIES
IONS
IRON
ISOMERS
ISOTOPE EFFECTS
ISOTOPIC EXCHANGE
OXIDES
OXYGEN 18
OXYGEN ISOTOPES
PROTONS
REACTION KINETICS
SHEETS
SILICON
TEMPERATURE
TRACER TECHNIQUES
VELOCITY
WATER