CMC Aircraft Brake Fabrication for Faster High-Heat Sintering
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Solution Overview
Problem
Existing methods for fabricating brake components and heat sinks for aircraft wheel and brake assemblies, such as carbon/carbon (C/C) composites and silicon carbide (SiC) based ceramic matrix composites, face challenges including long processing times, high temperatures, imprecise stoichiometric control, and failure to meet target thermal requirements.
Innovation Solution
A method involving infiltrating a carbon fabric with a slurry containing ceramic powder and a sintering aid, followed by warm pressing and spark plasma sintering to form a ceramic matrix composite brake component, using sintering aids like aluminum oxide and yttrium oxide, and optionally including boron carbide or silicon carbide, at pressures less than 10,000 psi and temperatures less than 1,950°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional fabrication methods (CVI, PIP, MI) are used to produce CMC brake components, then the components can be manufactured with ceramic matrix composite structure, but the processing time extends to well over one-hundred hours or requires inordinately high temperatures
Solution Approach 1:
The invention changes the processing parameters by using spark plasma sintering with a specific pressure range (1,000-10,000 psi) and temperature range (1,500-2,000°C) combined with sintering aids to achieve rapid densification in 5-50 minutes, dramatically reducing processing time compared to conventional methods
Solution Approach 2:
The invention introduces sintering aids (aluminum oxide, yttrium oxide, boron compounds) as intermediary substances that facilitate the sintering process by lowering the required processing time and temperature, enabling rapid densification without compromising material properties
2Reliability
If conventional fabrication methods are used, then brake components can be produced, but they often fail to satisfy target thermal requirements (heat capacities)
Solution Approach 1:
The invention optimizes processing parameters including pressure (1,000-10,000 psi), temperature (1,500-2,000°C), and atmosphere (inert or vacuum) to achieve superior densification and microstructure that results in brake components exceeding target heat capacity requirements by 10-20%
Solution Approach 2:
The invention uses composite materials consisting of carbon fabric reinforcement within a ceramic matrix (alumina, yttria, boron carbide, silicon carbide) to achieve both mechanical strength and superior thermal performance including heat capacity and thermal conductivity
3Manufacturing precision
If conventional fabrication methods are used, then brake components can be manufactured, but imprecise stoichiometric control is achieved
Solution Approach 1:
The invention performs preliminary mixing of ceramic powders and sintering aids in precise stoichiometric ratios before infiltration, ensuring accurate composition control is established before the sintering process begins
Solution Approach 2:
The invention replaces conventional mechanical mixing and processing with spark plasma sintering, which uses electrical discharge and plasma to achieve uniform heating and densification that maintains precise stoichiometric control throughout the component
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 approach reduces processing time and temperature, achieves precise stoichiometric control, and enhances thermal performance, resulting in brake components with higher heat capacity and density, suitable for aerospace applications.
Implementation Method 1
infiltrating a carbon fabric with a slurry containing a ceramic powder and a sintering aid
Implementation Method 2
sintering the green component via a spark plasma sintering process to form a sintered component
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
A method of fabricating a brake component made from a ceramic matrix composite is disclosed. In various embodiments, the method includes infiltrating a carbon fabric with a slurry containing a ceramic powder and a sintering aid; laying up the carbon fabric in a desired geometry to form a raw component; warm pressing the raw component to form a green component; and sintering the green component via a spark plasma sintering process to form a sintered component.