Effects of Coal Gasification Environments on Corrosion Behavior and Mechanical Properties of Siliconized Silicon Carbide

摘要

Potential applications of structural ceramic materials in coal gasifiers include high-temperature heat exchangers. This study is an evaluation of the effects of a coal gasification environment on the oxidation and corrosion behavior and mechanical properties of a candidate heat exchanger material, siliconized silicon carbide. The effects of exposure with and without acidic and basic coal slag coatings were studied. It was found that exposure of specimens from 1000 to 1300 exp 0 C without a slag coating resulted in silica scale growth by passive oxidation. Slag coatings had no effect at 1000 exp 0 C because the slags did not fuse. However, specimens exposed at 1250 and 1300 exp 0 C with slag coatings exhibited weight loss as a result of corrosive activity. The results of microscopic analyses suggest that a silica scale observed between the slag and silicon carbide may inhibit extensive corrosion after longer exposures. 14 refs., 15 figs., 9 tabs. (ERA citation 11:001948)