Abstract : A program to determine the phenomenological oxidation behavior of five commercial nickel-base alloys (IN-100, SM-200, Inco 713C, Rene 41, and U- 700) and one experimental alloy (Rene Y) is described to assure the intelligent application of these alloys and aid in the development of alloys with improved surface stability. The oxidation characteristics were established as a function of alloy composition, surface preparation, and environmental variables such as time (5 min to 1000 hrs), temperature (1400 to 2100 F), and air flow rate (to 75 ft/sec). The extent of scale and subscale reactions were measured, the reaction products identified and correlated with morphology, and the accompanying kinetics of their formation studied. The oxidation behavior of these alloys is complex due to the interplay between heterogeneous oxide growth, oxide interaction, oxide volatilization, and spalling. However, the general oxidation behavior is controlled by the competition between scaling and internal oxidation reactions which could be estimated by thermodynamics. Increased air flow, thermal cycling, and surface deformation generally decreased the oxidation resistance of the alloys. All the commercial alloys would be limited to service temperatures below 1800 F due to excessive spalling, oxide vaporization, or intergranular oxidation. Rene Y displayed potential application at temperatures in excess of 2000 F due to the lanthanum induced formation of a protective MnCr2O4 spinel oxide.