Carbon-Carbon Brake Disk Purification by Hydrogen Reduction
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Solution Overview
Problem
Carbon fiber reinforced carbon matrix composites used in high-performance braking systems, such as aircraft brakes, face contamination issues from carbon fiber precursors, the fiber preform needling process, CVI deposit, or pitch/resin infiltration processing, which negatively impact brake performance and structural integrity.
Innovation Solution
A method involving the use of a gaseous reducing agent, typically hydrogen gas, is introduced into a furnace containing a carbon fiber preform at controlled temperatures and pressures to react with and reduce contaminants, followed by purging to remove them, with multiple temperature and pressure stages to ensure complete contamination removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional manufacturing processes (carbon fiber precursors, needling, CVI, pitch/resin infiltration) are used, then carbon/carbon composite can be produced, but contamination occurs that negatively affects chemical and structural properties
Solution Approach 1:
The patent applies preliminary action by performing purification of the carbon fiber preform before the main carbonization and densification processes. The preform is purified at temperatures between 200-1000°C to remove contaminants from precursors, needling, and infiltration processes before they can affect the final composite structure.
Solution Approach 2:
The patent utilizes parameter changes by varying temperature (200-1000°C), pressure (vacuum to atmospheric), and gas flow rates during the purification process. These parameter changes enable selective removal of different types of contaminants while preserving the carbon fiber structure.
2Object-affected harmful factors
If purification processes are added to remove contamination, then contamination levels decrease, but process complexity and time increase
Solution Approach 1:
The patent merges the purification process with the existing carbonization and densification furnace operations. The purification is performed in the same equipment used for subsequent processing, combining multiple functions (purification, carbonization, densification) into a single integrated process flow, thereby reducing overall process complexity.
Solution Approach 2:
The patent employs an inert atmosphere (nitrogen or argon) during purification to prevent oxidation of carbon fibers while removing contaminants. This inert environment protects the carbon structure during the purification process without requiring additional complex equipment.
3Object-affected harmful factors
If high temperature treatment is applied to remove contaminants, then contamination is reduced, but energy consumption increases
Solution Approach 1:
The patent performs preliminary purification at relatively low temperatures (200-1000°C) before high-temperature carbonization and densification. This preliminary removal of contaminants at lower temperatures reduces the energy burden on subsequent high-temperature processing steps.
Solution Approach 2:
The patent optimizes temperature parameters by using the minimum effective temperature for contaminant removal and maintaining this temperature for sufficient time. This controlled parameter approach minimizes energy consumption while achieving effective purification.
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 effectively reduces contamination levels in carbon/carbon brake disks, enhancing their chemical and structural properties, leading to improved brake performance and reliability by minimizing the impact of metallic contaminants.
Implementation Method 1
purifying the preform with a gaseous reducing agent... causing the gaseous agent to react with and reduce a contaminate
Implementation Method 2
removing the gaseous reducing agent by one of a first pressure differential and a first purging gas flow
Implementation Method 3
carbonizing the preform, and densifying the preform
Implementation Method 4
carbonizing the preform
Data Source
AI summary
A method of manufacture for a carbon/carbon part including a method to remove contamination from an intermediate product of the carbon/carbon part and furnace utilizing a gaseous reducing agent hydrogen gas to reduce the contaminates, thereby causing the contaminates to transition to a gaseous state at relatively lower temperatures. A method to remove contamination from an intermediate product of the carbon/carbon part and furnace utilizing hydrogen gas to reduce the contaminates, thereby causing the contaminates to transition to a gaseous state at relatively lower temperatures.