J. Klower, Factors affecting the oxidation behaviour of thin Fe-Cu-Al foils - Part II: The effect of alloying elements: overdoping, MATER CORRO, 51(5), 2000, pp. 373-385
The oxidation behaviour of iron-chromium-aluminium alloys containing 7 mass
-% aluminium, additions of silicon and reactive elements (Hf, Y,Ti, Ce, La,
Zr) was investigated at temperatures ranging between 900 and 1300 degrees
C. It was found that a significant increase in the oxidation rate and in th
e depth of internal oxidation (so-called "overdoping") occurs above a criti
cal concentration of reactive elements. The critical upper limit of each re
active elements depends on the aluminium concentration, on the kind of the
respective reactive element and on the type and amount of other reactive el
ements. Alloys containing yttrium are only subject to internal oxidation at
yttrium concentrations of 0.08 mass-% and more. The susceptibility to "ove
rdoping" is significantly increased by additions of zirconium and titanium
to yttrium-containing alloys. Additions of hafnium, on the other hand, decr
ease the oxidation rate and the susceptibility to overdoping.