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Project Dates: 8/1/2007 - 9/30/2010

Area of Research: Materials

Federal Project Manager: Mark Freeman

Project Objective: The primary goal of this project is to determine if the high steam and CO₂ levels expected in coal-based oxy-fuel systems will cause severe oxidation degradation of alloys and coatings currently used in gas turbines. Objectives are to evaluate the performance of candidate alloys and coatings in 85% steam and 15% CO₂ (by volume), and then in an environment with reduced levels of steam to accommodate up to 5% O₂, which may represent excess oxygen needed to assure complete oxy-fuel combustion; to advance the existing knowledge of how steam (water vapor) affects the selective oxidation of high-temperature alloys; to investigate the effects of carbon and hydrogen on the oxidation and ductility of alloys exposed to H₂O-CO₂ mixtures; to examine the effects of contaminants such as SO₂ and alkali deposits ((Na, K)₂ SO₄, CaO) on the degradation of alloys in H₂O-CO₂ gas mixtures; and to examine the effects of steam and CO₂ gas mixtures on the degradation of yttria-stabilized zirconia thermal barrier coatings.