Aircraft Propulsion Component Passivation Against Hydrogen Embrittlement
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Solution Overview
Problem
Hydrogen embrittlement in aircraft propulsion system components due to hydrogen exposure reduces performance and requires frequent maintenance, especially in materials like steels, nickel alloys, and aluminium, which are crucial for their strength and weight ratios.
Innovation Solution
Exposing components to an oxygen-containing gas at suitable temperatures to form a passivation layer, which reduces hydrogen penetration and embrittlement, allowing the use of a wider range of materials and potentially extending component life and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If hydrogen is used as fuel in aircraft propulsion systems, then carbon dioxide emissions are reduced, but hydrogen embrittlement occurs in certain materials reducing component performance
Solution Approach 1:
The patent converts the harmful effect of hydrogen exposure into a beneficial passivation layer by controlling oxidation. By exposing components to oxygen at specific temperatures (200-600°C for stainless steel, 600-1200°C for nickel alloys), a protective oxide layer forms that actually protects the material from hydrogen embrittlement, thus converting the harmful hydrogen-m material interaction into a protective mechanism
Solution Approach 2:
The patent changes the physical and chemical parameters of the component surface through controlled thermal exposure to oxygen-containing atmospheres. By adjusting temperature ranges and exposure durations, the material surface undergoes oxidation that creates a passivation layer with different properties than the base material, thereby changing the interaction between hydrogen and the component material
2Strength
If conventional materials are used in hydrogen fuel systems, then component strength and weight ratios are maintained, but hydrogen penetration and embrittlement increase over time
Solution Approach 1:
The patent changes the surface parameters of conventional materials through controlled oxidation. By exposing materials like stainless steel, nickel alloys, and aluminium to oxygen at specific temperatures, the surface composition and structure are modified to create a passivation layer that reduces hydrogen penetration while preserving the bulk material's mechanical properties
Solution Approach 2:
The patent creates a composite structure at the material surface level, where a passivation layer (oxide compound) is formed on top of the base metal material. This composite structure combines the mechanical properties of the conventional material with the hydrogen-barrier properties of the oxide layer, achieving both strength and hydrogen resistance
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 passivation layer significantly reduces hydrogen embrittlement, enabling the use of a broader material selection and reducing maintenance needs, while maintaining or enhancing component performance and longevity.
Implementation Method 1
exposing one or more components that will contact hydrogen during engine running to an oxygen containing gas at a temperature suitable to cause passivation of at least part of the component
Data Source
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AI summary
A method of operating a hydrogen fuelled aircraft propulsion system (20), the method comprises exposing one or more components (36a, 38a, 40, 34a, 48, 50, 52, 54, 58) that will contact hydrogen during engine running to an oxygen containing gas at a temperature suitable to cause passivation of at least part of the component (36a, 38a, 40, 34a, 48, 50, 52, 54, 58).