Cool Side Coating for CMC Substrates Sealing Orifices

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Solution Overview

Problem

Ceramic or ceramic matrix composite materials used in high-temperature mechanical systems, such as gas turbine engines, can react with water vapor, leading to material recession and reduced mechanical properties, which can result in damage and reduced component lifetime.

Innovation Solution

A ceramic or ceramic matrix composite substrate with a cool side coating comprising a material having a flow temperature equal to or slightly less than the temperature of the heated gas environment, which melts and flows into damage orifices to seal them, reducing further exposure to hot gases and preventing performance loss until the substrate can be replaced or repaired.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a ceramic or CMC substrate is used in high-temperature environments, then mechanical and thermal properties are improved, but the material reacts with water vapor causing recession and reduced lifetime

Engineering Contradiction:

Improvehigh-temperature resistanceVSAvoidcomponent lifetime

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The coating system is divided into two distinct segments: a hot-side environmental barrier coating and a cool-side coating with sealant material. This segmentation allows each layer to perform its specific function - the hot-side coating protects against environmental attack while the cool-side coating provides self-sealing capability for through-orifice damage

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The cool-side coating acts as an intermediary that contains sealant material positioned to plug through-orifices. When damage occurs allowing hot gas penetration, this intermediary layer activates to seal the damage and prevent further substrate degradation

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the substrate is exposed to hot gases, then the component operates in its intended environment, but damage orifices allow hot gas flow to the cool side causing further damage

Engineering Contradiction:

Improveoperating environment compatibilityVSAvoidhot gas flow through damage

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The sealant material is pre-positioned in the cool-side coating before any damage occurs. This preliminary preparation ensures that when through-orifice damage happens, the sealant is already in place to immediately activate and seal the damage, preventing hot gas flow to the cool side

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The temperature differential that initially causes the problem (hot gases flowing through damage) is converted into a benefit by using the hot gas temperature to activate the sealant material. The harmful hot gas flow triggers the self-sealing mechanism that stops further damage

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Duration of action of stationary object

If a cool side coating with low flow temperature material is applied, then through-orifice damage is sealed extending service life, but the coating must be precisely formulated to melt at the right temperature

Engineering Contradiction:

Improveservice lifeVSAvoidcoating formulation precision

Core Design Contradiction:

Duration of action of stationary objectVSEase of manufacture

Solution Approach 1:

The flow temperature of the sealant material is precisely controlled as a critical parameter, formulated to be equal to or slightly less than the heated gas environment temperature. This parameter change ensures the sealant remains stable during normal operation but activates when exposed to hot gas temperatures, sealing damage automatically

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The sealant material utilizes phase transition from solid to liquid at a specific flow temperature. During normal operation below this temperature, the sealant remains solid and stable. When hot gas exposure occurs, the temperature rise triggers melting and flow, allowing the sealant to plug through-orifices and seal damage

Inventive Principle:

Principle #36Phase transitions

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 cool side coating effectively reduces the flow of hot gases through the substrate, minimizing further damage and extending the service life of the component by sealing orifices formed due to material recession.

Implementation Method 1

The cool side coating includes at least one material having a flow temperature equal to or slightly less than a temperature of the heated gas environment

Methodology Applied

Scientific EffectMelting: Melting

Data Source

PatentUS11643369B2Cool side coating for ceramic or ceramic matrix composite article

Publication Date: 2023.05.09 ROLLS ROYCE CORP

AI summary

An article may include a substrate including a ceramic or a ceramic matrix composite. The substrate defines a hot side surface configured to face a heated gas environment and a cool side surface opposite the hot side surface. The article also includes a cool side coating on the cool side surface. The cool side coating comprises at least one material having a flow temperature equal to or slightly less than a temperature of the heated gas environment.