Alloys for Advanced Steam Turbines—Oxidation Behavior

Advanced ultra-supercritical (USC) steam power plants promise higher efficiencies and lower emissions. The U.S. Department of Energy (DOE) aims to achieve 60% efficiency in coal-based power generation, requiring steam temperatures of up to 760°C. This study presents ongoing research on the oxidation behavior of candidate materials for advanced steam turbines, with a focus on estimating chromium evaporation rates from protective chromia scales. Due to the high velocities and pressures in advanced steam turbines, evaporation rates of CrO₂(OH)₂(g) are predicted to reach up to 5 × 10⁻⁸ kg m⁻²s⁻¹ at 760°C and 34.5 MPa, corresponding to a solid chromium loss of approximately 0.077 mm per year.