The oxidation of Ni3Al containing decomposed SiC-particles

Alloys of Ni3Al-(0, 1, 3, 5 vol.%)SiC were prepared via powder metallurgica l routes and their oxidation kinetics were studied between 1273 and 1473 K in air. The initially added SiC particles were unstable and decomposed with in the: matrix. It was found that initially added SiC increased the isother mal oxidation resistance to a certain extent, but adversely decreased the c yclic oxidation resistance because silica made the Al2O3-rich oxide layer m ore susceptible to spallation. For SiC-added alloys, the oxide scales consi sted primarily of alpha -Al2O3 and SiO2 with and without NiAl2O4. During ox idation, Al, Si and a bit of Ni diffused outwardly to form the oxide scale, while oxygen and most of Ni transported inwardly. (C) 2001 Elsevier Scienc e Ltd. All rights reserved.