CMAS-Resistant Thermal Barrier Coating via Laser Activated Reactive Layer
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Solution Overview
Problem
Traditional thermal barrier coatings in gas turbine engines are susceptible to spallation due to calcium-magnesium-alumino-silicate (CMAS) deposits, which limit durability and maximum temperature capability, and existing solutions like additional reactive layers are not activated until in service, with uncertain effectiveness.
Innovation Solution
A method involving the deposition of a reactive layer with predetermined CMAS reaction kinetics onto a thermal barrier coating, activated by laser scanning, which includes chemically conditioned CMAS powder and materials like Y2Zr2O7, to create a higher melting temperature barrier against environmental CMAS.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a traditional thermal barrier coating is used, then the component can operate at high temperatures, but the coating becomes susceptible to spallation due to CMAS deposits
Solution Approach 1:
The reactive layer is applied and activated before the component enters service, creating a pre-formed barrier that reacts with CMAS deposits. This preliminary action ensures the protective function is active from the start, preventing the spallation issues that occur with traditional coatings where the protective layer only forms after exposure to CMAS in service.
Solution Approach 2:
The coating system uses a composite structure combining a thermal barrier coating layer with a reactive layer containing specific compounds (such as alumina, magnesia, and cristobalite). This composite material approach allows the system to provide both thermal insulation and chemical resistance to CMAS deposits simultaneously.
2Object-affected harmful factors
If an extra protective layer is deposited over the thermal barrier coating, then CMAS resistance may be improved, but the layer is not activated until CMAS is encountered in service, making effectiveness uncertain
Solution Approach 1:
The reactive layer is pre-applied and activated during manufacturing before the component enters service. This ensures the protective chemistry is ready in advance to react with CMAS deposits, eliminating the uncertainty of whether the layer will activate properly when CMAS is first encountered during operation.
Solution Approach 2:
The reactive layer contains carefully selected chemical compounds with specific reaction kinetics designed to react with CMAS at operating temperatures. By controlling the composition and activation parameters, the layer reliably transforms into a protective barrier when exposed to CMAS, ensuring consistent effectiveness across different service conditions.
3Reliability
If a reactive layer with known CMAS reaction kinetics is deposited and heat treated, then spallation effects are mitigated, but the process adds manufacturing complexity
Solution Approach 1:
The reactive layer is applied as a thin, localized coating only where needed on the thermal barrier coating surface. This targeted approach provides spallation protection at the critical interface without requiring complex modifications to the entire coating system or component design.
Solution Approach 2:
The coating system integrates the reactive layer as part of a multi-layer composite structure that combines thermal barrier functionality with chemical resistance. This composite approach achieves enhanced spallation protection through material composition rather than complex structural designs or additional processing steps.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution significantly enhances CMAS resistance and reduces spallation, providing improved durability and temperature tolerance for gas turbine engine components by forming a robust, graded reactive layer that bonds with the thermal barrier coating.
Implementation Method 1
activating the reactive layer with a laser
Implementation Method 2
fusing the reactive layer and at least a portion of the thermal barrier coating
Data Source
AI summary
A method for forming a coating system on a component includes depositing a reactive layer with predetermined CMAS reaction kinetics on at least a portion of a thermal barrier coating. The method also includes activating the reactive layer with a scanning laser. A component, such as a gas turbine engine component, includes a substrate, a thermal barrier coating and a reactive layer. The thermal barrier coating is deposited on at least a portion of the substrate. The reactive layer is deposited on at least a portion of the thermal barrier coating. The reactive layer has predetermined CMAS reaction kinetics activated by laser scanning.