Corrosion behaviours of heat resisting alloys in steam at 8000C and 40 atm pressure

The corrosion behaviours of 3 heat resisting alloys, Inconel 600, Inconel 617 and Incoloy 800, have been studied in steam at 8000C and 40 atm pressure. A protective Cr2O3-rich scale is formed initially on the 3 alloys. After this introductory stage, the formation of nodular oxides on Inconel 600 and Inconel 617 drastically increases the weight gain rate. No evidence is found for the formation of these nodular oxides on Incoloy 800. The effect of the alloy composition, especially the concentration of Cr, on the nucleation and the growth of the nodular oxides is discussed. (orig.)