TRANSIENT OXIDATION OF NIAL

The transient oxidation stage of single crystal (001)NiAl was investig ated using scanning electron microscopy, transmission electron microsc opy, electron diffraction and high resolution electron microscopy. (00 1)NiAl was oxidized in air at 950 degrees C for 50 h in order to produ ce transient forms of alumina on the surface. After oxidation, an oxid e scale with plate-like surface morphology formed. The platelets on th e surface of the oxide were formed due to the growth of gamma-Al2O3, n ot theta-Al2O3. Randomly-oriented alpha-Al2O3 grains were observed at the oxide/metal interface. (C) 1998 Acta Metallurgica Inc.