Ceramic Seal Coating with Silicon Barrier for Rough CMC Surfaces

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Solution Overview

Problem

The implementation of ceramic matrix composite (CMC) materials in gas turbine engine systems faces challenges due to the surface roughness of CMCs, which leads to leakage and interaction issues with metallic components, potentially reducing thermal stability and durability.

Innovation Solution

A seal system comprising a ceramic component with a silicon-containing layer and a barrier layer, such as mullite, zircon, or hafnon, is used to address the surface roughness and interaction issues, with the silicon-containing layer reducing surface roughness and the barrier layer limiting silicon interaction with metallic elements, thereby enhancing sealing and thermal stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If CMC materials are used for high temperature resistance, then temperature capability is improved, but surface roughness causes leakage and interaction issues with metallic components

Engineering Contradiction:

Improvetemperature capabilityVSAvoidsealing performance

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

A silicon-containing layer is introduced as an intermediary between the CMC component and the metallic component. This intermediate layer fills the surface roughness of the CMC, providing a smooth sealing surface that prevents leakage while maintaining the high temperature resistance of the underlying CMC material.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The silicon-containing layer is applied in advance to the CMC surface before assembly with the metallic component. This preliminary action of smoothing the surface prevents subsequent leakage issues and interaction problems that would occur with the rough CMC surface directly contacting the metallic component.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If silicon-containing layer is applied to reduce surface roughness, then sealing performance is improved, but silicon may interact with metallic elements reducing thermal stability

Engineering Contradiction:

Improvesealing performanceVSAvoidthermal stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

A barrier layer is introduced as a second intermediary between the silicon-containing layer and the metallic component. This barrier layer prevents direct contact and interaction between silicon and metallic elements, thereby maintaining thermal stability while allowing the silicon layer to continue providing surface smoothing and sealing benefits.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Stability of the object's composition

If barrier layer is added to limit silicon interaction, then thermal stability is improved, but device complexity increases

Engineering Contradiction:

Improvethermal stabilityVSAvoidcoating system complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The barrier layer is designed with specific material properties and thickness parameters that optimize its function. By carefully controlling the parameters of the barrier layer (such as material composition and thickness), the system achieves thermal stability protection while minimizing the added complexity to acceptable levels.

Inventive Principle:

Principle #35Parameter changes

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 effectively reduces surface roughness, promotes mechanical bonding, and limits silicon migration, resulting in improved sealing and increased durability of the ceramic and metallic components, enhancing the thermal stability and performance of gas turbine engines.

Implementation Method 1

the silicon-containing layer reducing surface roughness

Methodology Applied

Scientific EffectSurface smoothing:

Implementation Method 2

the barrier layer limiting silicon interaction with metallic elements

Methodology Applied

Scientific EffectDiffusion barrier: Diffusion Barrier

Data Source

PatentUS11781486B2Ceramic component having silicon layer and barrier layer

Publication Date: 2023.10.10 RTX CORP

AI summary

A seal system includes a ceramic component that has a non-core-gaspath surface region that defines a first surface roughness and a core gaspath surface region. A metallic component is situated adjacent the non-core-gaspath surface region. A coating system is disposed on the ceramic component. The coating system includes a silicon-containing layer on the non-core-gaspath surface region and a barrier layer that has a first section on the silicon-containing layer and a second section on the core-gaspath region and that is connected to the first section. The surface of the barrier layer has a second surface roughness that is less than the first surface roughness. The first section is in contact with the metallic component and the second section serves as an environmental barrier on the core-gaspath region.