Oxidation Resistant Thermal Barrier Coating for Combustor Panels

Solution Overview

Problem

Thermal barrier coatings on combustor panels of gas turbines and jet engines degrade due to sintering, oxidation, and inter-diffusion, leading to reduced interfacial toughness and accelerated oxidation, which limits the lifetime of components.

Innovation Solution

A coating system comprising a first metallic coating applied by cathodic arc deposition, a second metallic coating by air plasma spray, and a ceramic top coating, providing enhanced oxidation resistance and mechanical interlocking for improved durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a conventional thermal barrier coating is applied to combustor panels, then the component can operate at high temperatures, but the coating degrades due to sintering, oxidation, and inter-diffusion, reducing lifetime

Engineering Contradiction:

Improveoperating temperatureVSAvoidcoating lifetime

Core Design Contradiction:

TemperatureVSDuration of action of stationary object

Solution Approach 1:

The coating system is divided into multiple functional layers: a first metallic bond coat layer applied by cathodic arc deposition, a second metallic bond coat layer applied by air plasma spray, and a ceramic top coat layer. Each layer serves specific functions to address different degradation mechanisms, with the first layer providing oxidation resistance and the second layer providing thermal barrier functionality.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses a composite coating structure combining different materials (metallic alloys and ceramic) and different deposition techniques (cathodic arc deposition and air plasma spray) to create a multi-layer system that simultaneously provides oxidation resistance, thermal insulation, and mechanical integrity at high temperatures.

Inventive Principle:

Principle #40Composite materials

2Temperature

If the ceramic layer and bond coat are exposed to high temperature service, then thermal barrier function is provided, but sintering and oxidation occur, reducing interfacial toughness

Engineering Contradiction:

Improvethermal barrier functionVSAvoidinterfacial toughness

Core Design Contradiction:

TemperatureVSStrength

Solution Approach 1:

The first metallic bond coat layer is applied by cathodic arc deposition before the ceramic top coat to create a pre-oxidized, adherent chromium oxide scale that protects the underlying bond coat from further oxidation and maintains interfacial toughness during service. This preliminary protective layer prevents degradation before it can compromise the interface.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Different regions of the coating system have different compositions and properties: the first bond coat layer contains oxidation-resistant alloys (e.g., nickel-chromium) specifically designed to form protective oxides, while the second bond coat layer provides thermal insulation, and the ceramic top coat provides the primary thermal barrier. Each layer is optimized for its specific local function.

Inventive Principle:

Principle #3Local quality

3Device complexity

If a single-layer thermal barrier coating is used, then the coating structure is simple, but oxidation resistance and durability are insufficient

Engineering Contradiction:

Improvecoating structureVSAvoidoxidation resistance

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The coating system is divided into multiple functional layers: a first metallic bond coat layer applied by cathodic arc deposition, a second metallic bond coat layer applied by air plasma spray, and a ceramic top coat layer. Each layer serves specific functions to address different degradation mechanisms, with the first layer providing oxidation resistance and the second layer providing thermal barrier functionality.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses a composite coating structure combining different materials (metallic alloys and ceramic) and different deposition techniques (cathodic arc deposition and air plasma spray) to create a multi-layer system that simultaneously provides oxidation resistance, thermal insulation, and mechanical integrity at high temperatures.

Inventive Principle:

Principle #40Composite materials

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 system significantly increases the oxidation resistance and lifetime of combustor panels by up to 20 times compared to conventional systems, preventing burn-back, spallation, and burn-through, while maintaining structural integrity and reducing thermal fatigue.

Implementation Method 1

a first metallic coating applied by cathodic arc deposition

Methodology Applied

Scientific EffectCathodic arc deposition: Cathodic Arc Deposition

Implementation Method 2

a second metallic coating by air plasma spray

Methodology Applied

Scientific EffectPlasma spray: Plasma Spray

Data Source

PatentUS10859267B2Oxidation resistant thermal barrier coating system for combustor panels

Publication Date: 2020.12.08 RTX CORP

AI summary

An oxidation resistant coating system for a turbine engine component includes a cathodic arc coating applied to a surface of the engine component, a thin APS metallic coating applied to a surface of the cathodic arc coating, and a ceramic top coating applied to a surface of the thin APS metallic coating to improve lifetime of the engine components.