Hot corrosion of TBC‐coated components upon combustion of low‐sulfur fuels

Materials and Corrosion, vol. 72, pp. 1643–1655

Abstract

Abstract Gas turbine reliability is a crucial requirement for passenger safety in aviation and a secure energy supply. Hence, corrosive degradation of combustor parts, vanes, and blades in gas turbines must be prevented. One of the most severe forms of corrosion is alkali‐sulfate‐induced hot corrosion, which is associated with internal sulfidation of components and is usually anticipated to fade in importance in the absence of sulfur. However, the literature suggests that hot corrosion might still occur in low‐sulfur combustion gases. In this study, established thermodynamic modeling methods are used to analyze the low‐sulfur hot corrosion regime. Liquid sodium chromate is found to be stable in these conditions. A comparison of calculation results and engine findings suggests that high alkali levels can negatively impact thermal barrier coating life even if sulfur is absent in the fuel. Laboratory tests are carried out to validate the chromate formation on MCrAlY‐coated specimens. It is shown that molten sodium chromate can alter the oxidation behavior of MCrAlY, promoting the formation of voluminous spinel. This represents a new and different form of hot corrosion compared to type I hot corrosion.

Authors 8

1. Christian Holländer corresponding Aachen

   RWTH Aachen University · Siemens Energy

   Affiliation as printed

   Large Gas Turbine Materials, Service Engineering Siemens Energy Mülheim an der Ruhr Germany

   RWTH Aachen University Templergraben 55 52062 Aachen Germany

   Large Gas Turbine Materials, Service Engineering Siemens Energy Mülheim an der Ruhr Germany

2. Stefan W. Kiliani

   Siemens Energy

   Affiliation as printed

   Large Gas Turbine Materials, Service Engineering Siemens Energy Mülheim an der Ruhr Germany

3. Werner Stamm

   Siemens Energy

   Affiliation as printed

   Large Gas Turbine Materials, Service Engineering Siemens Energy Mülheim an der Ruhr Germany

4. Oliver Lüsebrink

   Siemens Energy

   Affiliation as printed

   Large Gas Turbine Materials, Service Engineering Siemens Energy Mülheim an der Ruhr Germany

5. Harald Harders

   Siemens Energy

   Affiliation as printed

   Large Gas Turbine Materials, Service Engineering Siemens Energy Mülheim an der Ruhr Germany

6. E. Wessel

   Forschungszentrum Jülich

   Affiliation as printed

   IEK‐2 Forschungszentrum Jülich GmbH Jülich Germany

7. Michael Rolf Müller

   Forschungszentrum Jülich

   Affiliation as printed

   IEK‐2 Forschungszentrum Jülich GmbH Jülich Germany

8. L. Singheiser

   Forschungszentrum Jülich

   Affiliation as printed

   IEK‐2 Forschungszentrum Jülich GmbH Jülich Germany