Fibre-Reinforced UHTC Composites With Low-Pressure Slurry Infiltration

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Solution Overview

Problem

Existing methods for producing ultra-refractory ceramic materials face challenges such as high cost, lengthy production times, and insufficient mechanical properties due to porosity and inadequate fibre/matrix interfaces, limiting their reliability in extreme environments.

Innovation Solution

A process involving a ceramic suspension comprising ultra-refractory ceramics, dispersants, and optional functionalizing agents is used to infiltrate and consolidate fibres, achieving low porosity and high toughness through sintering at reduced temperatures and pressures, optimizing the fibre/matrix interface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional infiltration processes (CVI, PIP, RMI) are used to produce UHTC composites, then the material can be formed with ceramic matrix and reinforcement, but the production time becomes extremely lengthy and the cost becomes prohibitively high

Engineering Contradiction:
Improvematerial formationVSAvoidproduction time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent changes the physical state of the ceramic precursor from solid powder to liquid slurry, enabling infiltration at lower temperatures and shorter times. The liquid slurry can penetrate the preform matrix rapidly, and the subsequent drying and sintering cycles complete much faster than traditional vapor-phase or melt-based methods, directly addressing the lengthy production time issue while maintaining reliable material formation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces complex multi-step infiltration processes (CVI, PIP, RMI) with a simplified liquid slurry infiltration method. Instead of using vapor phase deposition or molten metal infiltration, the liquid slurry is applied and allowed to infiltrate naturally, eliminating the need for complex process equipment and extending infiltration cycles, thereby reducing production time while ensuring reliable composite formation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If high sintering temperatures and pressure are applied to eliminate porosity, then the material density improves, but the fibre mechanical properties are drastically modified and loss occurs

Engineering Contradiction:
Improveporosity reductionVSAvoidfibre mechanical properties
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The patent changes the sintering parameters by using liquid slurry infiltration which enables densification at lower temperatures and reduced pressures. The liquid state of the ceramic precursor allows for better wetting and bonding of fibres at milder conditions, achieving low porosity without subjecting the fibres to excessive thermal and mechanical stress that would degrade their mechanical properties.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The liquid slurry acts as an intermediary medium that facilitates infiltration and bonding between fibres and matrix at reduced temperatures. Instead of directly applying high energy to densify the material, the liquid slurry serves as a carrier that enables controlled infiltration and subsequent sintering at lower temperatures, protecting fibre mechanical properties while achieving the desired porosity reduction.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If the fibre/matrix interface is not properly optimized, then the composite can be manufactured, but the mechanical properties and toughness are insufficient

Engineering Contradiction:
Improvecomposite productionVSAvoidmechanical properties
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent changes the chemical composition parameters of the liquid slurry to include specific ceramic phases and additives that promote optimal fibre/matrix interface bonding. The liquid state allows for uniform distribution of ceramic particles and functional additives around fibres, creating a chemically optimized interface that enhances mechanical properties and toughness while maintaining ease of manufacture through the simple liquid infiltration process.

Inventive Principle:
Principle #35Parameter changes

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 results in fibre-reinforced UHTC composites with enhanced flexural strength, fracture toughness, and oxidation resistance, suitable for high-temperature applications with reduced residual porosity and improved mechanical properties.

Implementation Method 1

infiltrating a plurality of fibres with a ceramic suspension

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

drying the infiltrated composite material

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 3

consolidating the dried composite material at a temperature comprised in the range of 1700°-2000°C

Methodology Applied
Scientific EffectSintering: Sintering

Data Source

PatentEP3883906B1Process for obtaining composite, ultra-refractory, fibre-reinforced ceramic materials
Publication Date: 2025.08.06 CONSIGLIO NAT DELLE RICERCHE
  • EP3883906B1 patent drawingFigure 1a~1d
  • EP3883906B1 patent drawingFigure 2
  • EP3883906B1 patent drawingFigure 3a~3b

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.