Ceramic-Coated Carbon-Carbon Seal Ring for Oxidation Resistance
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Solution Overview
Problem
Gas turbine engine components, particularly seals, experience wear and oxidation issues that reduce their lifetime and effectiveness, necessitating improved wear protection and oxidation resistance.
Innovation Solution
A carbon-carbon composite seal ring with a monoaluminum phosphate binder layer and a ceramic layer, such as SiC or Si3N4, applied via atomic layer deposition, provides enhanced oxidation resistance and fills sub-surface porosity to extend the seal's lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If carbon-carbon composite seal ring is used, then wear resistance is improved, but oxidation resistance deteriorates
Solution Approach 1:
The seal ring uses a composite structure combining carbon-carbon composite material with ceramic coating layers. The carbon-carbon composite provides wear resistance while the ceramic coating (such as silicon carbide, silicon nitride, or oxidation-resistant ceramic) provides oxidation resistance, creating a multi-functional composite material system that resolves the contradiction between wear resistance and oxidation resistance.
Solution Approach 2:
The ceramic coating is applied selectively to specific surfaces of the seal ring that are most susceptible to oxidation, while maintaining the carbon-carbon composite structure in areas requiring high wear resistance. This localized application optimizes both properties where needed most.
2Object-affected harmful factors
If ceramic layer is applied to protect seal ring, then oxidation resistance is improved, but manufacturing complexity increases
Solution Approach 1:
The ceramic coating is applied as a pre-manufacturing step during the seal ring production process, before the seal ring is installed in the engine. This preliminary application of protective coating integrates the oxidation protection into the manufacturing workflow, reducing the need for separate post-manufacturing treatment steps and maintenance interventions.
3Strength
If binder layer is applied on seal ring surface, then adhesion is improved, but surface finish complexity increases
Solution Approach 1:
A binder layer (such as aluminum phosphate binder) is introduced as an intermediary substance between the carbon-carbon composite seal ring substrate and the ceramic coating. This binder layer enhances the adhesion and bonding between the two materials, ensuring the ceramic coating remains firmly attached to the seal ring during operation, while the binder is selected to be compatible with both surfaces.
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 carbon-carbon composite seal ring with a ceramic layer significantly improves oxidation resistance and wear protection, extending the seal's operational life and maintaining sealing effectiveness.
Implementation Method 1
applying a ceramic layer over the binder layer on at least one surface of the seal by atomic layer deposition
Data Source
AI summary
A sealing system includes a shaft, a rotor configured to rotate with respect to the shaft, and a carbon-carbon composite seal ring arranged around the shaft such that it seals against the rotor. The carbon-carbon composite seal ring includes a monoaluminum phosphate binder layer disposed on at least one surface of the carbon-carbon composite seal ring and a ceramic layer disposed over the monoaluminum phosphate binder layer on the least one surface of the carbon-carbon composite seal ring. A method of manufacturing a seal is also disclosed.