Slotted Ceramic TBC With Reactive Phase Against CMAS Infiltration

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Solution Overview

Problem

Ceramic thermal barrier coatings in gas turbine engines are vulnerable to damage from molten environmental contaminants like CMAS, leading to reduced strain tolerance, spallation, and premature component failure, which increases maintenance and operating costs.

Innovation Solution

A ceramic coating with local slotting and a reactive phase coating is applied to prevent CMAS infiltration and spallation, where the reactive phase coating reacts with environmental contaminants to form a solid barrier, and the slotting design reduces capillary forces and bridging, enhancing CMAS resistance and heat transfer performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a dense ceramic TBC coating is used to improve CMAS resistance, then CMAS infiltration resistance is improved, but strain tolerance deteriorates due to thermal expansion mismatch and stress accumulation

Engineering Contradiction:

ImproveCMAS infiltration resistanceVSAvoidstrain tolerance

Core Design Contradiction:

Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent utilizes a porous ceramic coating structure where controlled porosity is introduced to reduce capillary forces that drive CMAS infiltration. The porous structure allows the coating to accommodate thermal strain through pore collapse and deformation mechanisms, thereby maintaining strain tolerance while providing CMAS resistance through a tortuous infiltration path and reduced surface energy.

Inventive Principle:

Principle #31Porous materials

2Strength

If through-thickness pores and cracks are introduced to improve strain tolerance, then strain tolerance is improved, but CMAS resistance deteriorates due to increased infiltration pathways

Engineering Contradiction:

Improvestrain toleranceVSAvoidCMAS infiltration

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by creating a non-uniform pore distribution and orientation within the coating structure. Pores are strategically positioned and oriented to preferentially accommodate tensile strains while minimizing exposure to molten CMAS. The coating exhibits different local properties: regions with higher porosity for strain accommodation and regions with lower porosity or closed pores for CMAS barrier functionality.

Inventive Principle:

Principle #3Local quality

3Strength

If columnar TBC structure is used to improve strain tolerance, then strain tolerance is improved, but CMAS resistance deteriorates due to inter-columnar pore infiltration

Engineering Contradiction:

Improvestrain toleranceVSAvoidCMAS infiltration

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent employs a composite coating structure combining ceramic phases with different properties. The composite microstructure includes columnar grains with controlled internal porosity, binder phases that fill inter-columnar spaces, and potentially reactive barrier phases. This composite architecture maintains the strain tolerance benefits of columnar structure while mitigating CMAS infiltration through the composite action of different phases.

Inventive Principle:

Principle #40Composite materials

4Temperature

If TBC coating is applied to protect metal substrate from high temperature, then thermal protection is improved, but component life deteriorates due to spallation from CMAS attack

Engineering Contradiction:

Improvethermal protectionVSAvoidcomponent life

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-establishing a robust, strain-tolerant coating structure with optimized porosity and microarchitecture before CMAS exposure occurs. The coating is designed in advance to resist CMAS infiltration and prevent spallation through its inherent strain accommodation capabilities, thereby extending component life without requiring post-deposition modifications or repairs.

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 significantly extends the life of thermal barrier coatings by preventing CMAS infiltration and spallation, maintaining thermal strain tolerance and environmental resistance, thereby reducing maintenance and operating costs while improving heat transfer performance.

Implementation Method 1

the reactive phase coating reacts with environmental contaminants to form a solid barrier

Methodology Applied

Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

the slotting design reduces capillary forces and bridging, enhancing CMAS resistance

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Data Source

PatentUS20230228199A1Slotted ceramic coating with a reactive phase coating disposed thereon for improved CMAS resistance and methods of forming the same

Publication Date: 2023.07.20 GENERAL ELECTRIC CO

AI summary

A coated component including a slotted ceramic coating with a reactive phase coating disposed thereon for improved resistance to environmental contaminant compositions, along with methods of its formation, is provided. The coated component may include a substrate defining a surface, a ceramic coating disposed on the surface of the substrate, and a reactive phase coating disposed on the layer of environmental contaminant compositions. The ceramic coating includes a plurality of slots disposed in the ceramic coating forming segments of ceramic coating material.