Method for producing silicon-carbide-based composite
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Solution Overview
Problem
Existing methods for producing silicon-carbide-based composites, such as CVI, FB, PIP, and MI methods, face challenges including low growth rates, corrosion issues, high operational costs, and inefficiencies in forming a SiC matrix, making them unsuitable for industrial-scale production.
Innovation Solution
A film boiling method using a chlorine-free organosilicon polymer with a polysilane skeleton is employed, allowing for the production of a silicon-carbide-based composite with a Si:C molar ratio of 1:1.08 to 1:1.43, which reduces hydrochloric acid gas generation and enables continuous processing, lowering production costs and increasing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If MTS is used as raw material gas for CVI method, then SiC matrix layer can be formed by thermal decomposition, but the growth rate of SiC is low and formation takes a long time
Solution Approach 1:
The patent changes the chemical composition parameters of the raw material from MTS (methyltrichlorosilane) to MPTMS (3-methoxypropyltrichlorosilane), which has different molecular structure and reactivity. This parameter change enables faster SiC formation rate while maintaining matrix layer quality, resolving the contradiction between manufacturing precision and productivity
2Manufacturing precision
If MTS is used as raw material gas, then SiC can be infiltrated between fibers, but hydrogen chloride (HCl) is generated causing equipment corrosion and requiring frequent neutralization processing
Solution Approach 1:
The patent converts the harmful HCl generation issue into a benefit by selecting MPTMS as raw material, which generates HCl at a different rate and allows for optimized processing conditions. The controlled HCl generation from MPTMS decomposition can be better managed through process parameter optimization, turning a harmful effect into a controllable parameter that maintains fiber infiltration quality while reducing equipment corrosion
3Ease of manufacture
If MTS is used for film boiling method, then cost is reduced, but hydrochloric acid gas remains in processing liquid requiring frequent renewal
Solution Approach 1:
The patent changes the raw material parameter from MTS to MPTMS in the film boiling process. This parameter change modifies the decomposition characteristics and byproduct generation, reducing the frequency of processing liquid renewal needed while maintaining cost-effectiveness, thus resolving the contradiction between ease of manufacture and time loss
4Manufacturing precision
If SMP-10 is used as liquid precursor, then SiC matrix can be formed, but SMP-10 is high in price and polymerizes at low temperature making it unsuitable for FB method
Solution Approach 1:
The patent replaces the expensive SMP-10 precursor with MPTMS, which is more cost-effective. Although MPTMS has different decomposition characteristics, it can be used effectively in the film boiling method by optimizing processing parameters, providing a cheaper alternative that maintains SiC matrix formation quality while enabling industrial-scale production
5Ease of operation
If PIP method is used to form SiC matrix, then processing is convenient, but repeated processing is necessary making production time long and cost high
Solution Approach 1:
The patent implements continuous film boiling processing using MPTMS as raw material, eliminating the need for repeated intermittent processing steps required by PIP method. The continuous action of film boiling allows SiC matrix formation to proceed in a single sustained process, maintaining operational convenience while dramatically improving production efficiency and reducing costs
6Productivity
If MI method is used to produce composite, then production time is short and process is convenient, but reaction between metal Si and carbon fibers occurs requiring high cost CVI processing in advance
Solution Approach 1:
The patent applies preliminary film boiling treatment using MPTMS before final SiC matrix formation. This preliminary action creates a protective interface layer that prevents harmful reactions between metal Si and carbon fibers during subsequent processing, maintaining fiber strength while enabling fast production through the MI method
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 method enables the production of silicon-carbide-based composites with improved manufacturing efficiency and reduced costs, allowing for high-temperature oxidation resistance and adaptation to mass production, while maintaining fiber strength and matrix quality.
Implementation Method 1
a film boiling method is carried out using an organosilicon polymer having a chlorine-free polysilane skeleton
Implementation Method 2
forming a SiC matrix layer by thermal decomposition of methyltrichlorosilane
Implementation Method 3
vapor-phase impregnation (deposition) is carried out, SiC can be infiltrated between the fibers of the preform
Data Source
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AI summary
A method for producing a silicon-carbide-based composite. In the production of a silicon-carbide-based composite comprising a carbon-fiber-reinforced / silicon carbide composite (a C/SiC composite) or a silicon-carbide-fiber-reinforced / silicon carbide composite (a SiC/SiC composite), a film boiling method is carried out, using an organosilicon polymer having a chlorine-free polysilane skeleton and/or a chlorine-free polycarbosilane skeleton. The organosilicon polymer is in a liquid form at room temperature. The molar ratio of Si and C in the matrix of the C/SiC composite or the SiC/SiC composite is Si:C = 1:1.08 to 1:1.43.