화학공학소재연구정보센터
Materials Science Forum, Vol.461-464, 321-326, 2004
Coating design using computational codes for steam oxidation conditions
Thermodynamical calculations were performed using Thermo-Calc codes to obtained equilibrium diagrams of the heterogeneous system (steel P92, Fe-30Al-6Cr coating (wt. %))\(oxide compounds)\(O-2 + H2O gas mixture). Calculations were made for 650degreesC, constant water vapour pressure, equal 10(-1) atm, and variable oxygen partial pressure from. 1(.)10(-20) to 1(.)10(-1) atm. From obtained results indicate that in the steam gas enviromnents the highest volatile compounds form Mo, W and Cr oxides. Formation of volatile products depends on the oxygen pressure in the O-2 + H2O gas mixture. There is change of the principle volatile species in the Fe-Cr system, when at constant water vapour pressure, the oxygen partial pressure decrease. In such conditions there is a decrease of CrO2(OH)(2) vapour pressure, which is accompanied by an increase of Fe(OH)(2) vapour pressure. At higher oxygen partial pressure vapour pressure of CrO2(OH)(2) exceeds that of the most volatile aluminium species, Al(OH)(3), by many orders of magnitude.