Isothermal oxidation of a NiAI/TiB2 composite material has been investigated. Samples of NiAl with 0, l 0 and 20 vol.% TiB 2 particulates were oxidized at 1000, 1100 and 1200Β°C for 48 h. Thermogravimetric analysis was used to quantify oxide growth kinetics. Scanning electron microscopy with energy dispersive X-ray spectrometry was used along with X-ray diffraction to identify oxidation products and characterize oxide scale morphology. Oxidation was observed to follow parabolic kinetics. Rate of oxidation increased with TiB 2 content. The oxide that developed on the composite material formed an alumina scale that was not entirely protective. The development of microscopic channels allowed oxygen penetration below the alumina, resulting in subscale oxidation. Crystallites of TiO2 formed on the surface, increasing in size with oxidation temperature. Void formation between scale and substrate was much more extensive for the composite than for NiAI. Microstructural evidence indicates that TiB 2 dissociates within the void regions leading to outward diffusion of titanium through the oxide scale and formation of TiO 2 at the outer surface, while the AI203 scale forms at the metal-oxide interface.