A group of commercially available alloys was tested for resistance to synthetic combustion atmospheres at 1350 F, in controlled laboratory experiments, to determine their suitability for use as superheater-tubing materials. Variables in the corrosive environment included two concentration levels of sulphur dioxide, carbon monoxide, and alkali-metal salts. Evaluation on the basis of resistance to both scaling and subsurface corrosion showed that alloys of the 25–12 and 25–20 types were superior. AISI 304 also behaved very well in these tests. These results verify the conclusions of the field tests in installations burning low-sulphur natural gas or coal. The conditions obtained in burning high-sulphur, high-vanadium oil were not included in the laboratory tests.