Corrosion of ceramic materials in hot gas environment

The corrosion resistance of various oxide and non-oxide ceramic materials in hot gas environment was investigated. The tests were performed in a high temperature burner rig at 1450°C with 100 m/s gas flow speed and a water vapor pressure of 0.27 bar. The corrosion of the materials was characterized by the measurement of the weight balance and microstructural investigations. Non-oxide ceramic materials based on silicon exhibited the typical degradation behavior with the formation and evaporation of silicon hydroxides. A different behavior was found in case of oxide materials. Meanwhile ZrO(sub 2) was found to be stable in this environment, a high corrosion attack was observed for alumina and mullite. Oxide compounds e.g. rare earth disilicates or garnet structures decompose with the formation of a fairly dense oxide surface layer protecting the materials from further corrosion.