Carbon-Ceramic Body Production via Cellulose Carbonisation and Silicisation
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Solution Overview
Problem
The production of carbon-ceramic shaped bodies with improved mechanical properties and reduced costs, while avoiding additional materials and method steps such as separate carbonisation of precursor fibres and polymer matrices, is challenging due to issues like inhomogeneous microstructure, internal stresses, and poor fibre-matrix interfaces in existing methods.
Innovation Solution
A method involving carbonisation of a cellulose-based organic matrix reinforced with carbonisable textile structures followed by silicisation to form a carbon-ceramic shaped body with a carbon fibre-reinforced silicon carbide and silicon content, where the cellulose is optimised and the carbonisation process is controlled to achieve a porous structure that is then infiltrated with liquid silicon, enhancing fibre-matrix adhesion and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If separate carbonisation of precursor fibres and polymer matrix is performed, then fibre-matrix interface is improved, but production costs and energy input increase
Solution Approach 1:
The patent combines the carbonisation of precursor fibres and polymer matrix into a single simultaneous process step, eliminating the need for separate carbonisation operations. This merging approach maintains adequate fibre-matrix interface strength while significantly reducing production costs and energy consumption compared to sequential carbonisation methods.
2Reliability
If silicon coating is applied to improve oxidation resistance, then oxidation and temperature resistance increase, but production costs increase due to additional materials and method steps
Solution Approach 1:
The patent achieves oxidation resistance by controlling the chemical composition and reaction parameters during the silicisation process, rather than applying a separate silicon coating. By adjusting parameters such as silicon content, reaction temperature, and atmosphere composition, the polymer matrix itself develops oxidative stability, eliminating the need for additional coating materials and process steps.
3Ease of manufacture
If inhomogeneous ceramic composite materials are produced, then production process is simpler, but mechanical properties deteriorate
Solution Approach 1:
The patent employs local quality control through targeted fibre treatment and controlled silicisation conditions that create regions of optimized properties. The precursor fibres undergo specific surface modifications that enhance local bonding with the polymer matrix, while the silicisation process creates a gradient structure with improved mechanical properties at the fibre-matrix interface, ensuring high overall mechanical performance despite process simplicity.
4Stability of the object's composition
If large amount of metal powder is introduced at the beginning, then homogeneous distribution of metal is achieved, but production complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-treating the fibre surfaces with specific coatings or chemical modifications before composite formation. This preliminary preparation ensures that fibres readily bond with the polymer matrix during subsequent processing, achieving homogeneous distribution and strong interfaces without requiring complex mixing equipment or multi-step metal powder introduction procedures.
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 reduces production costs and energy input, maintains high mechanical properties like elongation at break and flexural modulus, and achieves a compact, high-performance carbon-ceramic material with improved thermal and oxidative resistance, suitable for aerospace and automotive applications, while using renewable cellulose as a cost-effective reinforcement.
Implementation Method 1
the silicon melt is infiltrated into the porous carbon precursor via capillary forces and reacts with the carbon skeleton to form silicon carbide
Implementation Method 2
a carbonisable shaped body having an organic matrix based on cellulose and reinforced with carbonisable textile structures has been carbonised to form a porous shaped body
Data Source
AI summary
The invention relates to a method of producing a carbon-ceramic shaped body comprising a carbon fibre-reinforced carbon matrix and a content of silicon carbide and silicon, characterised in that a carbonisable shaped body having an organic matrix based on cellulose and reinforced with carbonisable textile structures has been carbonised to form a porous shaped body and the porous carbonised shaped body is then subjected to a liquid silicisation to give the carbon-ceramic shaped body. This method is performable in an economically advantageously manner without losing the beneficial properties achievable according to the prior art.