In-Module Repair of Engine Seal Teeth Ceramic Coatings
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Solution Overview
Problem
Existing gas turbine engine inter-stage seals, particularly those with seal teeth, face challenges with maintainability and reliability due to uneven temperature distributions and spallation of the ceramic-based top layer, requiring complete component replacement and engine dismantling for repair.
Innovation Solution
A new material composition and method for repairing the ceramic-based top layer of seal teeth, involving a slurry composition with sintering additives like low melting glass and a nucleating agent, applied at room temperature and cured with localized heat at lower temperatures to restore toughness and adhesion without dismantling the engine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If the ceramic-based top layer is repaired using conventional methods, then the component can be restored, but the engine must be dismantled and the entire component replaced
Solution Approach 1:
The repair system is segmented into modular components: a localized heating device that can be positioned at the damage site, a separate material composition application system, and an independent curing mechanism. This segmentation allows the repair process to be performed in-module without dismantling the entire engine assembly.
Solution Approach 2:
A low melting glass sintering additive acts as an intermediary material between the damaged ceramic surface and the repair material. This intermediary enables bonding at lower temperatures, facilitating in-module repair without requiring high-temperature equipment that would necessitate engine disassembly.
2Manufacturing precision
If high temperature curing is applied to repair the ceramic layer, then the repair material cures properly, but the underlying layers are damaged
Solution Approach 1:
The curing temperature parameter is changed from conventional high temperatures to a lower temperature range enabled by the low melting glass sintering additive. This parameter change allows the repair material to cure properly while maintaining the integrity of the underlying nickel-aluminide bond coat and base layer, which would be damaged by high temperatures.
Solution Approach 2:
The low melting glass sintering additive undergoes phase transition at relatively low temperatures, enabling the curing process to occur without exposing the underlying layers to damaging high temperatures. This phase transition mechanism allows proper curing while protecting the multi-layer structure.
3Loss of time
If the ceramic-based top layer is repaired in-module, then engine dismantling is avoided, but heat exposure to the rest of the component increases
Solution Approach 1:
The heating and curing process is applied locally only to the damaged area rather than to the entire component. This localized approach minimizes heat exposure to the rest of the engine component while still achieving proper repair curing, thus reducing the harmful thermal effects on surrounding areas.
Solution Approach 2:
The repair system uses localized heating devices and targeted material application that segment the thermal process to only the necessary repair zone, preventing unnecessary heat exposure to the entire component while maintaining repair effectiveness.
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 enables in-module repair of seal teeth, maintaining the integrity of the underlying layers, providing erosion resistance, and ensuring a smooth surface, while minimizing heat exposure to the rest of the component, thus enhancing maintainability and reliability.
Implementation Method 1
cured with localized heat at lower temperatures to restore toughness and adhesion
Implementation Method 2
the sintering additive converts crystalline phases during processing to restore toughness of the ceramic-based top layer
Implementation Method 3
the sintering additive converts crystalline phases during processing
Implementation Method 4
the nucleating agent converts the sintering additive to a ceramic material to reduce brittleness
Data Source
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AI summary
A method (100) of repairing a multi-layer component (50) of an engine (10) in-module includes identifying a damage location (202) on the multi-layer component (50). The damage location (202) extends at least partially into a ceramic-based top layer (56) of the multi-layer component (50). The method (100) further includes depositing a material composition (206) onto the damage location (202) at a first temperature range so as to cover the damage location (202). The material composition (206) includes one or more sintering additives. Further, the method (100) includes applying localized curing to the material composition (206) deposited at the damage location (202) at a second temperature range, the second temperature range being higher than the first temperature range.