Geometrically Segmented Insulating Topcoat for Spallation Control

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Solution Overview

Problem

Existing thermal insulation coatings in gas turbine engines suffer from spallation due to severe operating environments, leading to increased maintenance costs and reduced durability.

Innovation Solution

A geometrically segmented thermally insulating topcoat with surface features and faults extending through the coating, designed to dissipate internal stresses and prevent spallation by allowing thermal expansion and contraction without significant stress buildup.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the thermal insulation coating is made thicker to improve insulation performance, then the strain tolerance improves, but the coating becomes more prone to spallation due to stress buildup

Engineering Contradiction:

Improvethermal insulation performanceVSAvoidcoating durability

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The coating is divided into segmented portions separated by faults or cracks that extend vertically through the coating thickness. This segmentation allows the coating to accommodate thermal expansion and contraction stresses without building up sufficient stress to cause spallation, thereby enabling thicker coatings to maintain both insulation performance and durability.

Inventive Principle:

Principle #1Segmentation

2Reliability

If geometric surface features are formed on the substrate to induce vertical cracks, then strain tolerance increases, but the manufacturing complexity increases

Engineering Contradiction:

Improvestrain toleranceVSAvoidcoating fabrication

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Geometric surface features (such as pyramids, ribs, or protrusions) are formed on the substrate or bond coat before applying the thermal insulation coating. These pre-formed features serve as stress concentration points that guide the formation of vertical faults or cracks during coating deposition or subsequent thermal cycling, thereby simplifying the overall process compared to attempting to create controlled cracks after coating application.

Inventive Principle:

Principle #10Preliminary action

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 enhances strain tolerance and durability of the coating, reducing the need for cooling air and maintaining efficient engine operation at higher temperatures.

Implementation Method 1

designed to dissipate internal stresses and prevent spallation by allowing thermal expansion and contraction without significant stress buildup

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP4636224A1Geometrically segmented coating for thermal insulation and abradability protection

Publication Date: 2025.10.22 RTX CORP

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AI summary

A process of preventing spallation for a geometrically segmented thermally insulating top coat on an article, the process including forming a surface feature with a surface feature tip on a surface of the article; disposing the thermally insulating topcoat over the surface feature; and forming segmented portions that are separated by faults extending through the thermally insulating topcoat from the surface feature tip.