Airfoil Environmental Barrier Topcoats for Volatilization and CMAS Resistance
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Solution Overview
Problem
Gas turbine engine airfoils face durability challenges due to severe environmental conditions, including volatilization and CMAS exposure, which can lead to material loss and structural integrity reduction, as existing environmental barrier coatings are not optimized for varying conditions between suction and pressure sides.
Innovation Solution
The airfoil features a silicon-containing ceramic wall with a first environmental barrier topcoat on the suction side and a second topcoat on the pressure side, each of different compositions tailored to resist volatilization and CMAS infiltration respectively, and additional topcoats on the leading and trailing ends for enhanced protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single environmental barrier coating composition is used on the airfoil, then the coating can be applied uniformly and manufactured easily, but it cannot effectively resist both volatilization on the suction side and CMAS infiltration on the pressure side simultaneously
Solution Approach 1:
The patent applies different coating compositions to different regions of the airfoil based on local environmental conditions. The suction side receives a coating optimized for volatilization resistance, while the pressure side receives a coating optimized for CMAS infiltration resistance. This local differentiation resolves the contradiction by tailoring protection to specific operational challenges at each location.
Solution Approach 2:
The environmental barrier coating is segmented into multiple zones with different compositions. The airfoil surface is divided into suction side and pressure side regions, each receiving a specialized coating formulation. This segmentation allows the system to address multiple protection needs simultaneously without requiring a single complex universal coating.
2Reliability
If location-specific topcoats are applied to different sides of the airfoil, then protection against volatilization and CMAS infiltration is optimized, but the manufacturing process becomes more complex
Solution Approach 1:
Different topcoat compositions are applied to specific locations on the airfoil - the suction side receives volatilization-resistant coating while the pressure side receives CMAS-resistant coating. This local quality approach optimizes durability for each environmental exposure while maintaining a systematic manufacturing process.
Solution Approach 2:
The solution uses composite coating structures where different material compositions are combined in specific spatial arrangements. Each topcoat layer is formulated as a composite material optimized for its specific operational environment, achieving enhanced durability through material diversity rather than process complexity.
3Object-affected harmful factors
If the airfoil wall is made of silicon-containing ceramic, then it provides good baseline environmental resistance, but it remains vulnerable to volatilization and CMAS attack without additional protective topcoats
Solution Approach 1:
The airfoil structure combines silicon-containing ceramic substrate with specialized environmental barrier topcoats forming a composite material system. The substrate provides baseline thermal and structural properties, while the topcoats provide specialized chemical resistance against volatilization and CMAS infiltration, together achieving comprehensive protection that neither component could provide alone.
Solution Approach 2:
The environmental barrier topcoats are applied in advance to the airfoil surface before service exposure. This preliminary protective action prevents direct contact between the silicon-containing ceramic and harmful environmental factors, maintaining structural integrity by blocking degradation pathways before they can compromise the underlying material.
Data Source
AI summary
An airfoil includes an airfoil wall that defines a leading end, a trailing end, and suction and pressure sides that join the leading end and the trailing end. The airfoil wall is formed of a silicon-containing ceramic. A first environmental barrier topcoat is disposed on the suction side of the airfoil wall, and a second, different environmental barrier topcoat is disposed on the pressure side of the airfoil wall. The first topcoat is vaporization-resistant and the second topcoat is resistant to calcium-magnesium-aluminosilicate.