EFFECTS OF AL ADDITION AND MINOR ELEMENTS ON OXIDATION BEHAVIOR OF FECR ALLOYS

It is shown that the addition of aluminium is very effective for the h igh temperature oxidation resistance of FeCr alloys. 1% aluminium prod uces a continuous protective Al2O3 oxide for FeCr alloy that contains more than 13% of chromium. However this aluminium content is not enoug h for the high temperature resistance of thin foils and a 5% aluminium content is needed since the substrate plays the role of an aluminium reserve susceptible to oxidation. Impurity elements such as sulphur ar e detrimental and give rise to scaling of the oxide layer. Active elem ents such as Y, Ce, La, Zr are therefore necessary to tie up sulphur a nd increase the life of the alloys.