Carbon-Carbon Composite Encapsulation for Brake Disc Wear Resistance

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Solution Overview

Problem

Carbon-carbon composite materials, such as brake discs, face issues with isotropic carbon's brittle nature leading to poor frictional characteristics and reduced wear performance due to fracturing under braking loads, necessitating improved structural and frictional properties.

Innovation Solution

A method involving chemical vapor deposition (CVD) or chemical vapor infiltration (CVI) to deposit an initial carbon material into a porous carbon fiber preform, followed by infusion and pyrolysis of an isotropic resin to form isotropic carbon, which is then encapsulated with graphitizable carbon to enhance mechanical and frictional properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If isotropic resin is pyrolyzed to form isotropic carbon within the porous preform, then the preform density is enhanced and rigidity is improved, but the frictional characteristics deteriorate and wear performance reduces due to the brittle nature of isotropic carbon

Engineering Contradiction:
ImproverigidityVSAvoidwear performance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent creates a composite carbon structure by combining isotropic carbon (from pyrolyzed resin) with graphitizable carbon (from subsequent CVD/CVI deposition). This composite approach allows the isotropic carbon to provide density and rigidity enhancement while the graphitizable carbon layer provides improved frictional characteristics and wear resistance, resolving the contradiction between strength improvement and reliability deterioration

Inventive Principle:
Principle #40Composite materials

2Quantity of substance

If isotropic carbon is formed within the porous preform, then the carbon content and density increase, but the material becomes more prone to fracturing under braking loads

Engineering Contradiction:
Improvecarbon contentVSAvoidfracture resistance
Core Design Contradiction:
Quantity of substanceVSStrength

Solution Approach 1:

The patent applies different carbon types in different locations within the composite structure. The isotropic carbon is formed within the pores to increase density and carbon content, while the graphitizable carbon is deposited on the exterior surfaces and interfaces where it provides fracture resistance and mechanical strength. This spatial differentiation of material properties resolves the contradiction between increasing carbon content and maintaining fracture resistance

Inventive Principle:
Principle #3Local quality

3Reliability

If graphitizable carbon is deposited after isotropic carbon formation, then wear performance and friction characteristics improve, but the manufacturing process complexity increases

Engineering Contradiction:
Improvewear performanceVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent performs the graphitizable carbon deposition as a preliminary or subsequent treatment step that builds upon the already-formed isotropic carbon structure. By using CVD or CVI processes that can be integrated into existing manufacturing workflows, the additional deposition step adds wear performance improvement without requiring fundamentally new manufacturing equipment or processes, thus limiting the increase in manufacturing complexity

Inventive Principle:
Principle #10Preliminary action

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 encapsulation of isotropic carbon with graphitizable carbon significantly improves wear performance, friction characteristics, and thermal properties, reducing the likelihood of fracturing and enhancing the service life of carbon-carbon composite components.

Implementation Method 1

depositing an initial carbon material into a porous carbon fiber preform using chemical vapor deposition (CVD) or chemical vapor infiltration (CVI)

Methodology Applied
Scientific EffectChemical vapor deposition: Chemical Vapour Deposition

Implementation Method 2

pyrolyzing the infused isotropic resin to form carbon within pores of the rigidized porous carbon fiber preform

Methodology Applied
Scientific EffectPyrolysis: Pyrolysis

Data Source

PatentEP3401294B1Carbon-carbon composites including encapsulated isotropic carbon and production method thereof
Publication Date: 2021.03.31 HONEYWELL INTERNATIONAL INC
  • EP3401294B1 patent drawingFigure 1
  • EP3401294B1 patent drawingFigure 2~4
  • EP3401294B1 patent drawingFigure 5~6

AI summary

The disclosure describes a method of forming a carbon-carbon composite component including depositing an initial carbon material into a porous preform using chemical vapor deposition (CVD) or chemical vapor infiltration (CVI) to form a rigidized porous preform, infusing the rigidized porous preform with an isotropic resin, pyrolyzing the infused isotropic resin to form an isotropic carbon within pores of the rigidized porous preform, and encapsulating the isotropic carbon with a graphitizable carbon to form the carbon-carbon composite component.