OXIDATION OF Cu-Cr-Ni ALLOYS UNDER 0.1 MPa PURE O_2 AT 800℃

The oxidation behaviors of Cu-20Cr-20Ni and Cu-20Cr-40Ni alloys at 800 ℃ under 0.1 MPa pure oxygen were studied. The kinetic curves for oxidation of both alloys followed nearly the parabolic rate law. The scales are complex and consist of a CuO outer layer and an inner larer composed of Cu2O, NiO, Cr2O3. Metallic chromium particles in Cu2O matrix result from kinetic factors. The oxidation of Cu-20Cr-40Ni alloy is very severe because a continuous Cr2O3 layer did not form at the ioterface of oalde scale and alloy. For Cu-20Cr-40Ni alloy, the oxidation is restrained because there is a nearly continuous Cr2O3 layer at the okide scale/alloy. The scale formed on Cu-20Cr-20Ni alloy is much thicker than that on Cu-20Cr40Ni alloy The composition of scale changes evendently as a function of the distance from the alloys/scale illterface. This morphology is more complex than that of metals or binary alloys.