Multi-Phase Environmental Barrier Coating for Gas Turbine Oxidation Resistance

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Solution Overview

Problem

Gas turbine and hypersonic engines require lightweight materials with robust mechanical properties across a wide temperature spectrum, and existing coatings fail to provide adequate environmental and thermal protection while maintaining chemical and mechanical compatibility with structural materials.

Innovation Solution

A multi-component environmental barrier coating comprising a metal silicide phase, a crystalline ceramic phase, and an amorphous ceramic phase, with specific volume fractions and aspect ratios, applied using a plasma torch process to form an oxidation-resistant bond coat layer that can repair cracks and provide additional protection with a top coat layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a coating is applied to protect structural materials from combustion gas and harsh environment, then environmental protection and thermal protection are improved, but chemical compatibility and mechanical compatibility with the article may deteriorate

Engineering Contradiction:

Improveprotection from combustion gas and harsh environmentVSAvoidchemical and mechanical compatibility

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The coating is divided into multiple functional layers: a bond coat layer containing metal silicide phase, crystalline ceramic phase, and amorphous ceramic phase; and an environmental barrier top coat layer. Each layer is optimized for specific functions - the bond coat provides oxidation resistance and adhesion, while the top coat provides environmental protection, ensuring both protection and compatibility.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The bond coat layer uses a composite microstructure consisting of three phases: metal silicide phase (providing adhesion and oxidation resistance), crystalline ceramic phase (providing thermal stability), and amorphous ceramic phase (providing flexibility and crack resistance). This composite structure achieves both environmental protection and mechanical/chemical compatibility.

Inventive Principle:

Principle #40Composite materials

2Duration of action of stationary object

If the coating provides robust mechanical properties across wide temperature spectrum, then durability is improved, but material complexity increases

Engineering Contradiction:

Improvedurability across temperature spectrumVSAvoidcoating composition complexity

Core Design Contradiction:

Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

The coating design specifies precise parameter ranges: metal silicide phase aspect ratio of 1:1 to 50:1 (optimally 2:1 to 10:1), volume fractions of each phase (metal silicide: 20-80%, crystalline ceramic: 25-75%, amorphous ceramic: 1-30%), and particle size distributions. These controlled parameters ensure durable performance across wide temperature ranges while managing complexity through specification.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Different regions of the coating have optimized properties: the bond coat layer has higher metal silicide content for adhesion and oxidation resistance at the substrate interface, while the top coat has higher ceramic content for environmental protection. The aspect ratio and distribution of phases are locally optimized for their specific functional requirements.

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 coating effectively protects structural materials from oxidation and thermal degradation, maintaining durability and mechanical compatibility, and extends the service life of components by sealing cracks and accommodating thermal expansion mismatches.

Implementation Method 1

injecting the mixed powder feedstock into a plasma torch that is directed at a surface of the article to at least partially melt the silicide powder, the ceramic powder, and the glass powder

Methodology Applied

Scientific EffectPlasma: Plasma

Implementation Method 2

accommodating thermal expansion mismatches

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS11661380B2Multi-environmental barrier coating, processes for coating articles, and their coated articles

Publication Date: 2023.05.30 RTX CORP

AI summary

A coated article including an article having a surface; an oxidation resistant bond coat layer deposited on the surface, the oxidation resistant bond coat layer comprising a metal silicide phase, a crystalline ceramic phase and an amorphous ceramic phase, wherein the metal silicide phase has an aspect ratio greater than 1:1 but less than 50:1.