CMAS mitigation for TBCs using a novel aluminum-phosphate based overlay coating

Environmental degradation of aerospace turbine components is a major concern for aircraft and power generation systems, and various surface treatments are utilized to extend the lifetimes of these critical components. This Phase II project is targeted toward extending the durability of thermal barrier coatings (TBCs) on hot section turbine components. TBCs are highly susceptible to degradation by corrosion at elevated temperatures, and degradation from Calcium Magnesium Alumino Silicate (CMAS) is of particular concern to the Navy. CMAS is a byproduct of decomposed jet fuel and can attack critical components. The mitigation of CMAS effects by use of thin overlay coatings on TBCs is the primary focus of this SBIR project. In Phase I, ATFI demonstrated that a low-cost, solution-based inorganic coating was effective in infiltrating the TBC and limiting corrosion by CMAS. Various TBC architectures were evaluated and, in most cases, positive impact was realized from the presence of the overlay coating. In Phase II, ATFI will work with engine manufacturers to further develop this concept and test performance under burner rig exposure conditions. Additionally, prototype parts will be developed and made available for testing by the Navy which will aide in preparation for transition planning and Phase III participation.