Turbine Thermal Barrier Coating with Depth-Varying Properties

Solution Overview

Problem

Turbine engine thermal barrier coatings (TBCs) face challenges with cracking and spallation due to thermal cycling and foreign object damage, leading to reduced structural integrity and increased maintenance needs, as well as susceptibility to calcium-magnesium-aluminum-silicon (CMAS) contamination, which compromises their thermal insulation and durability.

Innovation Solution

The implementation of engineered surface features (ESFs) and engineered groove features (EGFs) within the TBC layer, combined with depth-varying material properties and a CMAS-retardant material, to enhance adhesion, crack containment, and aerodynamic efficiency, thereby preventing crack propagation and maintaining thermal insulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a thermal barrier coating (TBC) layer is applied to turbine components, then thermal insulation is improved, but the coating becomes susceptible to cracking and spallation due to thermal cycling and foreign object damage

Engineering Contradiction:

Improvethermal insulationVSAvoidcrack resistance

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The TBC layer is designed with depth-varying material properties, creating a gradient structure where the inner portion has different fracture toughness and elastic modulus than the outer portion. This local differentiation allows the inner layer to absorb thermal stress while the outer layer maintains thermal insulation, resolving the contradiction between thermal protection and crack resistance.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention uses composite material structures with multiple layers or regions having different material compositions and properties. The TBC layer incorporates materials with varying fracture toughness, elastic modulus, and thermal conductivity at different depths, creating a composite structure that simultaneously provides thermal insulation and resistance to cracking and spallation.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If the TBC layer material properties are made uniform, then manufacturing simplicity is maintained, but crack propagation and spallation damage increase under thermal cycling

Engineering Contradiction:

Improvecoating application simplicityVSAvoidresistance to spallation

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The TBC layer is designed with depth-varying material properties, creating a gradient structure where the inner portion has different fracture toughness and elastic modulus than the outer portion. This local differentiation allows the inner layer to absorb thermal stress while the outer layer maintains thermal insulation, resolving the contradiction between thermal protection and crack resistance.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention changes material parameters (fracture toughness, elastic modulus, thermal conductivity) as a function of depth within the TBC layer. This parameter gradient is achieved through controlled variation of material composition during application or through multi-layer construction, enabling the coating to withstand thermal cycling without spallation while maintaining manufacturability.

Inventive Principle:

Principle #35Parameter changes

3Temperature

If the TBC layer is made thicker to improve thermal insulation, then thermal protection is enhanced, but the coating becomes more susceptible to crack propagation and spallation

Engineering Contradiction:

Improvethermal protectionVSAvoidcoating integrity

Core Design Contradiction:

TemperatureVSStrength

Solution Approach 1:

The TBC layer is designed with depth-varying material properties, creating a gradient structure where the inner portion has different fracture toughness and elastic modulus than the outer portion. This local differentiation allows the inner layer to absorb thermal stress while the outer layer maintains thermal insulation, resolving the contradiction between thermal protection and crack resistance.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention uses composite material structures with multiple layers or regions having different material compositions and properties. The TBC layer incorporates materials with varying fracture toughness, elastic modulus, and thermal conductivity at different depths, creating a composite structure that simultaneously provides thermal insulation and resistance to cracking and spallation.

Inventive Principle:

Principle #40Composite materials

4Productivity

If the TBC layer surface is left smooth, then aerodynamic efficiency is maintained, but calcium-magnesium-aluminum-silicon (CMAS) contamination adheres more readily to the surface

Engineering Contradiction:

Improveaerodynamic efficiencyVSAvoidCMAS adhesion

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The TBC layer is designed with depth-varying material properties, creating a gradient structure where the inner portion has different fracture toughness and elastic modulus than the outer portion. This local differentiation allows the inner layer to absorb thermal stress while the outer layer maintains thermal insulation, resolving the contradiction between thermal protection and crack resistance.

Inventive Principle:

Principle #3Local quality

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 isolates cracks and prevents spallation, maintaining the structural integrity of the TBC layer and enhancing the durability and efficiency of turbine engine components by containing cracks and reducing CMAS adhesion, thus extending the engine's service life and operational efficiency.

Implementation Method 1

The TBC provides an insulating layer over the component substrate, which reduces the substrate temperature

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 2

Exemplary depth-varying material properties include fracture toughness, elastic modulus, porosity and thermal conductivity that vary from the TBC layer inner to outer surface

Methodology Applied

Scientific EffectFracture mechanics: Fracture Mechanics

Implementation Method 3

apply a calcium-magnesium-aluminum-silicon (CMAS)-retardant material over the TBC layer to retard reaction with or adhesion of CMAS containing combustion particulates to the TBC layer

Methodology Applied

Scientific EffectChemical resistance:

Data Source

PatentUS10323533B2Turbine component thermal barrier coating with depth-varying material properties

Publication Date: 2019.06.18 SIEMENS ENERGY GLOBAL GMBH & CO KG

AI summary

A thermal barrier coating (TBC) with depth-varying material properties is formed on a turbine component. Exemplary depth-varying material properties include physical ductility, strength and thermal resistivity that vary from the TBC layer inner to outer surface. Exemplary ways to modify physical properties include application of plural separate overlying layers of different material composition or by varying the applied material composition during the application of the TBC layer. Various embodiment described herein also apply a calcium-magnesium-aluminum-silicon (CMAS)-retardant material over the TBC layer to retard reaction with or adhesion of CMAS containing combustion particulates to the TBC layer. In other embodiments the CMAS retardant material is also applied within engineered groove features (EGFs) that are formed in the TBC surface.