Fibre-Reinforced UHTC Composite Processing With Low-Porosity Densification
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Solution Overview
Problem
Existing ultra-refractory ceramic materials lack suitable thermal shock resistance and resistance to crack propagation, leading to insufficient mechanical and chemical properties for reliable components in extreme environments, and current production methods are costly and time-consuming.
Innovation Solution
A ceramic suspension comprising ultra-refractory ceramic components, dispersants, and compounds like scandium and yttrium is used to infiltrate fibres, followed by consolidation at controlled temperatures, resulting in a composite material with low porosity and high toughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional infiltration processes (CVI, PIP, RMI) are used to produce UHTC composites, then the material achieves high temperature resistance, but the production cost increases and production time extends significantly
Solution Approach 1:
The patent changes the chemical composition parameters of the ceramic suspension by incorporating specific compounds (Sc2O3, Y2O3, La2O3) at controlled concentrations (0.1-15 vol. %) alongside ultra-refractory ceramics (55-95 vol. %) and SiC (0-30 vol. %). This compositional modification enables the material to achieve high temperature resistance while reducing processing time and cost compared to conventional methods
Solution Approach 2:
The patent creates a composite ceramic suspension system combining multiple ceramic phases (ultra-refractory ceramics, SiC) with metal oxide compounds (Sc2O3, Y2O3, La2O3) dispersed in a liquid medium. This composite approach allows the material to exhibit enhanced high-temperature properties while improving infiltration efficiency and reducing production time
2Temperature
If conventional infiltration processes are used to produce UHTC composites, then the material achieves high temperature resistance, but the production cost increases
Solution Approach 1:
The patent modifies the suspension composition parameters by incorporating cost-effective metal oxide compounds (Sc2O3, Y2O3, La2O3) at optimized concentrations with ultra-refractory ceramics and SiC. This parameter optimization achieves high temperature resistance while controlling material costs and simplifying the manufacturing process compared to conventional expensive precursors
Solution Approach 2:
The patent replaces expensive conventional precursors with more economical ceramic powders and metal oxide compounds that can be directly incorporated into the suspension. This substitution reduces material costs while maintaining the high temperature resistance required for UHTC composites
3Volume of stationary object
If porosity is eliminated by processing at high sintering temperatures with mechanical pressure, then material density improves, but fibre properties undergo drastic modification leading to loss of mechanical properties
Solution Approach 1:
The patent changes the sintering parameters by processing at moderate temperatures (1700-2000°C) for limited durations without excessive mechanical pressure. The modified suspension composition with Sc2O3, Y2O3, and La2O3 compounds enables effective porosity reduction and densification at these milder conditions, preserving fibre mechanical properties
Solution Approach 2:
The metal oxide compounds (Sc2O3, Y2O3, La2O3) act as intermediary substances that facilitate sintering and densification at lower temperatures. These compounds mediate the consolidation process, enabling porosity elimination without requiring harsh sintering conditions that would damage the reinforcing fibres
4Temperature
If UHTC materials are used to withstand temperatures above 2000°C, then high temperature resistance is achieved, but thermal shock resistance and crack propagation resistance are insufficient
Solution Approach 1:
The patent creates a composite microstructure combining ultra-refractory ceramic particles, SiC, and metal oxide compounds (Sc2O3, Y2O3, La2O3) in a fibre-reinforced matrix. This composite structure provides high temperature resistance while the fibre reinforcement and composite architecture improve thermal shock resistance and crack propagation resistance, enhancing overall reliability
5Strength
If fibre content is increased to improve toughness, then mechanical properties improve, but infiltration and densification become more difficult
Solution Approach 1:
The patent optimizes the suspension composition parameters to include ultra-refractory ceramics (55-95 vol. %), SiC (0-30 vol. %), and metal oxide compounds (0.1-15 vol. %) in a liquid dispersant. This optimized composition achieves good flow and infiltration characteristics even with high fibre content (up to 70 vol. %), enabling effective densification while maintaining high fracture toughness
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 process produces fibre-reinforced UHTC composites with low residual porosity, high flexural strength, and fracture toughness, suitable for temperatures above 1600°C, reducing production time and cost while enhancing mechanical properties.
Implementation Method 1
infiltrating a plurality of fibres selected from carbon fibres, silicon carbide fibres and mixtures thereof, with a ceramic suspension
Implementation Method 2
drying the infiltrated composite material
Implementation Method 3
consolidating the dried composite material at a temperature comprised in the range of 1700°-2000° C.
Data Source
AI summary
The present invention relates to a process for preparing a composite, ultra-refractory, fibre-reinforced ceramic material obtained through the infiltration of carbon and/or silicon carbide fibres with a ceramic suspension comprising yttrium, lanthanum and/or scandium compounds, and the subsequent densification of the composite. The fibre-reinforced UHTC compounds obtained by the process can be used for making items intended for use in extreme temperature and pressure conditions.