This research extends understanding of particle erosion-corrosion processes to metal alloy systems based on nickel, cobalt and iron. A wide variety of erosive conditions of particle loading, velocity, angle of incidence, and temperature are employed in the experiments in controlled gaseous environments. Mechanisms of deformation and heat evolution at the specimen surface are analyzed. Of particular interest is the possible development of concentration gradients near the alloy surface, internal oxidation, and extensive transient oxidation, all of which can contribute strongly to the failure of the alloys to form protective oxide layers. %%% Erosion-corrosion processes are responsible for serious material degradation in a wide range of industrial processes, including gas turbines and coal gasifiers. This research should aid in the design of alloys that resist this type of degradation.