Preceramic Resin Formulation for Ceramic Matrix Composites
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Solution Overview
Problem
Conventional preceramic polymers, such as polycarbosilane, have low viscosity and high mass loss, cracking, and porosity issues when used to form ceramic matrix composites, limiting their application in high-temperature aerospace and industrial applications, and existing methods for producing ceramic materials like silicon carbide are costly and time-intensive.
Innovation Solution
A preceramic resin formulation combining polycarbosilane and organically modified silicon dioxide polymers with tailored viscosity and fillers, which are cured and ceramified to form composite materials with improved mechanical and thermal properties, reducing mass loss and porosity, and enabling the production of ceramic matrix composites through a wet filament winding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional preceramic polymers like polycarbosilane are used to form ceramic matrix composites, then the processing is simpler, but the material exhibits high mass loss, extensive cracking, high porosity, and high shrinkage
Solution Approach 1:
The patent combines polycarbosilane with organically modified silicon dioxide polymer and filler particles to create a composite preceramic formulation. This composite approach allows the system to maintain processability while the silicon dioxide component reduces cracking and the filler particles reduce porosity and shrinkage during ceramification
Solution Approach 2:
The patent modifies the physical and chemical parameters of the preceramic formulation by adding specific filler particles and adjusting the polymer composition ratio. These parameter changes transform the material properties to achieve lower mass loss, reduced cracking, and improved ceramic yield without sacrificing ease of processing
2Reliability
If high loading of fillers is used to reduce porosity, then porosity decreases, but viscosity increases making the material ineffective
Solution Approach 1:
The patent uses filler particles with specific size distributions (bimodal or multimodal) where different sized particles occupy different spatial regions and roles. Smaller particles fill voids between larger particles, achieving high filler loading with minimal viscosity increase because the smaller particles efficiently pack spaces without creating excessive resistance to flow
3Ease of manufacture
If conventional preceramic polymers are used, then processing is easier, but ceramic yield is low and mass loss is high
Solution Approach 1:
The patent creates a composite preceramic system combining polycarbosilane with organically modified silicon dioxide polymer. The silicon dioxide component has inherently lower mass loss during pyrolysis, and when combined with the polycarbosilane, the overall formulation achieves reduced mass loss and higher ceramic yield while maintaining the processing advantages of the original polymer
4Strength
If multiple infiltration cycles are used to produce ceramic matrix composites, then material density and strength improve, but production cost and time increase
Solution Approach 1:
The patent incorporates filler particles and optimizes the preceramic formulation composition before the ceramification process. This preliminary preparation ensures that the material achieves optimal density and reduced porosity in a single infiltration cycle, eliminating the need for multiple sequential infiltration treatments and significantly improving production efficiency
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 approach results in composite materials with high ceramic yield, low mass loss, and reduced cracking, significantly lowering production costs and time while maintaining structural integrity at high temperatures, making them suitable for high-temperature applications like rocket motors and aerospace components.
Implementation Method 1
conventional preceramic polymers, such as polycarbosilanes, have a low viscosity (less than about 200 cP), which limits their practical use in the preparation of CMCs where the preceramic polymer provides the matrix of the CMC
Data Source
AI summary
A preceramic resin formulation comprising a polycarbosilane preceramic polymer, an organically modified silicon dioxide preceramic polymer, and, optionally, at least one filler. The preceramic resin formulation is formulated to exhibit a viscosity of from about 1,000 cP at about 25° C. to about 5,000 cP at a temperature of about 25° C. The at least one filler comprises first particles having an average mean diameter of less than about 1.0 μm and second particles having an average mean diameter of from about 1.5 μm to about 5 μm. Impregnated fibers comprising the preceramic resin formulation are also disclosed, as is a composite material comprising a reaction product of the polycarbosilane preceramic polymer, organically modified silicon dioxide preceramic polymer, and the at least one filler. Methods of forming a ceramic matrix composite are also disclosed.