The experimental setup included a simple furnace with a gas feeder, which is schematically shown in Figure 1. The furnace was composed of a ceramic tube, hot coils, a refractory, and a flask for feeding different types of corrosive gases. A block specimen was placed in the middle of the furnace in a high-temperature environment. Single particle impact tests on block specimens ( mm or mm) in high-temperature corrosive environments were conducted with a compact gas gun, which is schematically shown in Figure 1. Glass beads 2, 3, and 5 mm in diameter were projected at 50 and 70 ms−1 into specimens that were coated with either a corrosion product or an oxide film. The specimen surfaces at high temperature were observed with a video camera connected to a computer. The spalled and detached areas of the films caused by impact were measured using image processing. The impact craters were observed by scanning electron microscopy (SEM). The contact pressure was calculated as the impact energy divided by the indentation volume, which was geometrically calculated by the crater diameter.