Science Underpinning TBC Design to Overcome the CMAS Threat to Progress in Gas Turbine Technology
Technical Report,05 Feb 2008,30 Jun 2014
The Regents of the University of California, Santa Barbara Campus Santa Barbara United States
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This project aimed to develop the scientific foundation for TBC concepts that are sufficiently robust to withstand CMAS degradation in current and future gas turbine engines with expected material temperatures 1300 deg. C. The overarching goal was to elucidate the dynamics of the infiltration-d issolution -crystallization processes that eventually arrest the CMAS penetration into the TBC, and to assess the robustness of the affected TBC system under static and changing thermal gradients. The approach involved three distinct activities i characterizing and understanding CMAS related damage mechanisms in field specimens provided by industrial collaborators, ii investigating the reaction kinetics of different CMAS and CMASTBC combinations using differential scanning calorimetry and isothermal furnace exposures, and iii evaluating the thermomechanical response of infiltrated systems to varying thermal gradients using a laser based test facility developed at UCSB under this project. Modeling aspects were addressed through collaborations with other investigators. The overarching themes were microstructure evolution, its connection to material and environmental parameters, and its thermo-mechanical implications. The expected benefit to the US Navy would be i a science-based strategy toguide coating design for CMAS environments through suitable control of the composition and architecture, ii an enhanced scientific foundation for high temperature materials and i ii the training and diversity of human resources in this important area.