Ceramic Brake Discs via Expanded Graphite Solid Binder
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Solution Overview
Problem
The existing processes for manufacturing ceramic brake discs are costly and time-consuming, requiring a liquid binder and carbonization steps that are unnecessary when using expanded graphite as a solid binder.
Innovation Solution
A process that eliminates the need for a liquid binder and carbonization by using expanded graphite, which acts as a solid binder, allowing for melt infiltration under non-oxidizing conditions, and includes a densification step with predensified expanded graphite and consolidated carbon fiber bundles to enhance mechanical and thermal properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a liquid binder is used in the manufacturing process, then the green body can be formed and hardened, but additional steps of hardening and carbonization are required, increasing process complexity and time
Solution Approach 1:
The patent removes the liquid binder component from the manufacturing process entirely, replacing it with expanded graphite as a solid binder. This extraction eliminates the need for hardening and carbonization steps that are specifically required for liquid binder systems, thereby reducing process complexity while maintaining green body formation capability
Solution Approach 2:
The patent changes the physical state parameter of the binder from liquid to solid (expanded graphite). This parameter change fundamentally alters the binding mechanism, allowing the green body to maintain structural integrity through the expanded graphite's physical properties rather than requiring chemical hardening and carbonization processes
2Reliability
If liquid binder and carbonization steps are used, then the green body can be properly formed and stabilized, but the manufacturing process becomes more time-consuming and expensive
Solution Approach 1:
The patent extracts and eliminates the time-consuming carbonization step from the process by using expanded graphite as a solid binder that does not require thermal decomposition. The green body stability is achieved through the physical binding properties of expanded graphite rather than through carbonization, thereby significantly reducing manufacturing cycle time while maintaining reliability
Solution Approach 2:
The patent replaces expensive, time-intensive liquid binder systems with a simpler, more economical solid binder (expanded graphite) that achieves the same functional result without requiring additional processing steps, thereby reducing both time and cost while maintaining green body stability
3Productivity
If traditional manufacturing processes with liquid binder are used, then the ceramic component can be produced, but the cost and process time increase due to additional hardening and carbonization steps
Solution Approach 1:
The patent merges the binding function with the reinforcement function by using expanded graphite that serves both as binder and as carbon source for SiC formation. This consolidation eliminates separate hardening and carbonization steps, thereby improving productivity and manufacturing efficiency while maintaining process simplicity through the use of a single functional material
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 results in a more cost-efficient ceramic component with improved mechanical and thermal properties, suitable for brake discs, offering higher thermal conductivity and stability while avoiding the steps of binder hardening and carbonization.
Implementation Method 1
expanded graphite works in principle as a solid binder
Implementation Method 2
the green body would be heated to the melting temperature of silicon under non-oxidizing atmosphere
Implementation Method 3
The green body is finally infiltrated with a melt of carbide forming metal, like liquid silicon
Data Source
AI summary
The present invention relates to a process for the manufacture of a ceramic component comprising the following steps: a) providing expanded graphite and/or a precursor of expanded graphite, b) mixing of a composition comprising the material provided in step a) and one or more materials of the group consisting of carbon fibers and consolidated carbon fiber bundles and obtaining a mixture, wherein the composition does not comprise a liquid binder, c) densifying a defined amount of the mixture obtained in step b) in a mold and, c1) if a precursor of expanded graphite is provided in step a), heating up the densified mixture in the mold to at least 300°C, d) obtaining a green body of the ceramic component and e) subjecting the green body to reactive melt infiltration, wherein the process neither comprises a step of hardening a binder nor a step of carbonizing the green body of the ceramic component. Furthermore, the invention relates to components obtainable from the process and their use as brake discs, brake pads and clutches.