Synergistic Effects in the Environmental Degradation of Ceramic Coatings in Gas-Turbine Engines and its Mitigation
Abstract
The purpose of this action is to add a FY23 funding increment in the amount of $150,000.50 for a new start Grant, GRANT#13612780.-The unpredictability in the environmental degradation of hot-section components of gas-turbine engines used in Navy aircraft compromises the critically needed durability and reliability of these assets. In this context, the most relevant environmental corrodents include those ingested by the engine: (i) siliceous particles (from sand/dust/ash, referred to as calcia-magnesia-aluminosilicate orCMAS); (ii) seasalt (from marine environment); and (iii) sulfates (from dust). As the operating temperatures of gas-turbine enginesare rising for more power and higher efficiency, the environmental degradation of the hot-section components, in particular ceramiccoatings, is becoming more severe and unpredictable. This is most likely due to a combination of environmental corrodents acting inconcert, resulting in synergistic severe degradation effects. However, when the degradation in the engine hardware in the field is characterized, it is difficult to tell how that particular mode of degradation took place. While there is scattered ongoing researchon evaluating, understanding, and mitigating degradation of ceramic thermal-barrier coatings (TBCs) and environmental-barrier coatings (EBCs) due to CMAS-alone, seasalt-alone, and sulfates-alone, there is a lack of coordinated, systematic basic research effort onthe combined-corrodents effects. The proposed research aims to address this important need.The broad objectives of the proposed research, that integrates experiments and modeling efforts, are: (a) to understand the melting behavior of various combinations of relevant environmental corrodents; (b) to understand the high-temperature interactions between combined-corrodents and coating ceramics,and the nature of the synergistic environmental degradation; and (c) based on the understanding, to design and demonstrate approaches for mitigating the degradation. The proposed research is divided into three interrelated tasks and several subtasks within.In Task 1, various combinations of the relevant environmental corrodents (CMASs, seasalt, sulfates) will be mixed, and their chemistries, reactivities, and melting/flow behavior will be characterized. These targeted experiments will be informed by basic thermodynamic modeling. These results will provide insights into any synergistic effects on the high-temperature behavior of the various combinations of the corrodents.In Task 2, TBC, EBC, and TEBC ceramics of relevant compositions will be fabricated. High-temperature interactions between these coating ceramics and the combined-corrodents from Task 1 will be realized, and the resulting materials characterizedextensively. These results, in conjunction with basic thermodynamic modeling, will be analyzed to provide a deep understanding of the nature of the high-temperature interactions, in particular enhanced/accelerated degradation caused by synergistic effects of the combined-corrodents.In Task 3, based on the understanding from Tasks 1 and 2, we will design and demonstrate innovative #chemical# and #microstructural# approaches to mitigate combined-corrodents-induced degradation of TBCs.At the end of the 3-year project we willhave accomplished the following: (1) identify and characterize synergistic effects of combined-corrodents (CMASs, seasalt, sulfates); (2) gain deep understanding of the high-temperature interactions between combined-corrodents and coatings ceramics (TBC, EBC, TEBC); (3) design and demonstrate innovative #chemical# and #microstructural# approaches for mitigating synergistic degradation of TBCs; (4) train graduate students in materials research; (5) disseminate research findings via presentations and several high-quality journal publications; and (6) communicate the findings to OEMs for possible commercialization.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 12, 2023
- Source ID
- N000142312384
Entities
People
- Nitin P Padture
Organizations
- Brown University
- Office of Naval Research
- United States Navy