Selective Hot Gas Channel Coating for Turbomachine Components

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Solution Overview

Problem

Existing methods for coating components in turbomachines' hot gas channels face challenges such as aerodynamic disadvantages from complete coating, risk of crack formation during post-processing, and inefficiencies in targeted area protection against oxidation and hot gas corrosion.

Innovation Solution

A method involving the application of a particle-infused binder to specific areas of the component, followed by heat treatment, where the binder dissolves and the coating material, such as aluminum, diffuses into the surface, providing targeted protection while maintaining a smooth, aerodynamically advantageous surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the entire surface of the component is coated to provide comprehensive protection against oxidation and hot gas corrosion, then the protection coverage is improved, but the aerodynamic performance deteriorates due to the rougher surface of the coating

Engineering Contradiction:
Improveprotection against oxidation and hot gas corrosionVSAvoidaerodynamic disadvantage
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies coating only to specific areas of the component surface that are particularly vulnerable to oxidation and hot gas corrosion, rather than coating the entire surface. This selective area coating approach protects critical zones while maintaining smooth aerodynamic surfaces in non-critical areas, thus resolving the contradiction between comprehensive protection and aerodynamic performance

Inventive Principle:
Principle #3Local quality

2Object-generated harmful factors

If post-processing of the coating is performed to improve surface smoothness, then the aerodynamic performance is improved, but the risk of cracking in adjacent layer areas increases

Engineering Contradiction:
Improveaerodynamic disadvantageVSAvoidrisk of cracking
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The patent performs surface smoothing and preparation before applying the coating, rather than attempting post-processing of the coated surface. This preliminary action ensures a smooth base surface that promotes uniform coating application and adhesion, eliminating the need for subsequent machining or grinding that could cause cracking in the coating or adjacent layers

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If gas phase deposition is used to apply the coating, then the coating can be applied uniformly, but the component would have to be covered in a much more complex and almost complete manner, increasing device complexity

Engineering Contradiction:
Improveuniform coating applicationVSAvoidcomplexity of covering the component
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent extracts the coating application process from the constraints of gas phase deposition by using liquid or slurry-based coating methods. This allows the coating to be applied in a controlled, selective manner to only the areas requiring protection, using simple application techniques such as brushing, spraying, or dipping, thereby avoiding the need for complex complete coverage and extensive masking required by gas phase deposition

Inventive Principle:
Principle #2Taking out (Extraction)

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

This method allows for selective coating of high-risk areas, reducing the risk of crack formation and aerodynamic inefficiencies, while providing effective protection against oxidation and hot gas corrosion, with economic advantages over complete coating methods.

Implementation Method 1

The component, partially covered with the particle-infused binder, is then heat-treated, whereby the binder dissolves and the coating material remains on the component

Methodology Applied
Scientific EffectDissolution:

Implementation Method 2

the coating material remains on the component (at the surface or diffuses into it)

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP3428308B1Method for coating a component for the hot gas channel of a turbomachine
Publication Date: 2024.09.04 MTU AERO ENGINES GMBH
  • EP3428308B1 patent drawingFigure 1a
  • EP3428308B1 patent drawingFigure 1b~3b
  • EP3428308B1 patent drawingFigure 2

AI summary

The invention relates to a method for coating a component (6) intended for the hot gas channel of a turbomachine (1), wherein the coating material (35) in the form of particles (31) in a mixture with a binder (32) is applied to the uncoated component surface (30) and the component (6) with the particle-impregnated binder (32) is then heat-treated in such a way that the binder (32) dissolves and the coating material (35) remains on the component (6).