ausblenden:
Schlagwörter:
FeAl; FeAl2; Microstructure; Oxidation
Zusammenfassung:
The oxidation behavior of binary Fe-Al alloys with an aluminum content between 58 and 64 at.% was studied by isothermal and cyclic oxidation experiments in a temperature range of 900-1000 A degrees C. The parabolic rate constants were determined to be comparable to those of B2-ordered Fe-48Al. All investigated alloys exhibited a fine-scaled, lamellar microstructure (< 300 nm lamellar spacing), which was a result of the eutectoid decomposition of the high-temperature phase Fe5Al8 into FeAl and FeAl2. None of these two phases showed a preferential oxidation. At 900 A degrees C theta-Al2O3 formed, whereas at 1000 A degrees C a transformation of the initially formed theta-Al2O3 to the slower growing and passivating alpha-Al2O3 was confirmed by grazing incidence X-ray diffraction measurements.
