Carbon Seal Coating Interface for Low-Friction Housing Contact
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Solution Overview
Problem
Existing carbon seals in gas turbine engines face wear and friction issues due to direct contact with metallic housings, leading to reduced performance and lifespan.
Innovation Solution
A seal assembly featuring a housing with a carbide-based coating and a diamond-like carbon coating, which separates the carbon seal from the housing, reducing friction and wear by creating a carbon-on-carbon interface and generating a lubricant graphitic material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a carbon seal directly contacts a metallic housing, then the seal provides adequate sealing, but friction and wear increase significantly
Solution Approach 1:
A diamond-like carbon (DLC) coating is applied to the metallic housing surface to serve as an intermediary layer between the carbon seal and the metal housing. This DLC coating creates a carbon-on-carbon interface that reduces friction and wear while maintaining the sealing function, preventing direct contact between the carbon seal and metallic housing.
Solution Approach 2:
The housing surface is treated with a composite coating structure consisting of a carbide-based adhesive layer (such as tungsten carbide or chromium carbide) combined with a diamond-like carbon top layer. This composite material structure provides both strong adhesion to the metal substrate and low-friction surface properties for the carbon seal interface.
2Device complexity
If a carbon seal directly contacts a metallic housing, then the structure remains simple, but sub-surface heating and friction increase
Solution Approach 1:
The diamond-like carbon coating acts as a thermal and friction intermediary layer that reduces sub-surface heating by providing a low-friction interface. This coating layer prevents excessive heat generation at the contact interface while maintaining structural simplicity through a straightforward coating application process.
3Duration of action of moving object
If coatings are applied to the housing surface, then friction and wear are reduced, but manufacturing complexity increases
Solution Approach 1:
A two-layer composite coating system is employed: a carbide-based adhesive layer (tungsten carbide or chromium carbide) applied via conventional coating methods, followed by a diamond-like carbon top layer. This composite approach balances manufacturing feasibility with performance requirements, as each layer serves a specific function and can be applied using established coating technologies.
Solution Approach 2:
The coating parameters (thickness, composition, application method) are optimized to achieve the desired performance while maintaining ease of manufacture. The carbide layer thickness is controlled to provide adequate adhesion, while the DLC layer thickness is optimized for low-friction performance, allowing for practical manufacturing implementation.
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 reduces wear and friction, improving the long-term performance and lifespan of the carbon seal by maintaining a low friction coefficient and reducing sub-surface heating.
Implementation Method 1
reducing friction and wear by creating a carbon-on-carbon interface
Implementation Method 2
generating a lubricant graphitic material
Data Source
AI summary
A seal assembly includes a housing that includes a seal flange at least partially defining a seal opening. A carbon seal is located at least partially in the seal opening and includes a first axially facing surface. The seal flange includes an axially facing surface that has a carbide based coating and a diamond-like carbon coating in engagement with the first axially facing surface on the carbon seal.