Composite Ceramic Material Silicon Infiltration
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Solution Overview
Problem
Existing composite ceramic materials used in thermo-mechanical applications, such as brake disks and aerospace components, face issues with wear resistance, thermal stability, and resistance to thermal shocks, along with challenges like silicon segregation and internal tensions during infiltration, which affect their performance and longevity.
Innovation Solution
A method involving the introduction of metals like tin, iron, and titanium into the ceramic matrix, either as additives or through infiltration with molten silicon, to enhance mechanical properties, reduce infiltration temperature, and create a compositionally homogeneous or graded ceramic matrix, thereby improving thermo-mechanical properties and reducing silicon segregation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If composite ceramic materials are used in braking systems and aerospace applications, then resistance to impact and compression is improved, but wear resistance and thermal stability are insufficient
Solution Approach 1:
The patent applies composite materials by combining carbon fibers with a ceramic matrix consisting of silicon carbide and crystalline silica. This composite structure provides both the required mechanical strength for impact and compression resistance while the ceramic matrix delivers superior wear resistance and thermal stability, resolving the contradiction between mechanical strength and reliability in high-temperature applications.
Solution Approach 2:
The patent changes the chemical composition parameters of the matrix by incorporating specific ratios of silicon carbide (30-70 wt%) and crystalline silica (30-70 wt%). This parameter optimization ensures the material achieves both high mechanical strength from the carbon fiber reinforcement and excellent wear resistance and thermal stability from the tailored ceramic matrix composition.
2Strength
If liquid silicon infiltration is used to increase cohesion of carbon fibers, then cohesion features are improved, but silicon segregation occurs causing internal tensions and cracks
Solution Approach 1:
The patent converts the harmful effect of silicon segregation into a beneficial feature by intentionally incorporating crystalline silica (30-70 wt%) into the matrix design. The controlled presence of silica transforms the segregation issue into a design advantage, where the silica provides structural stability and prevents crack propagation, thereby maintaining both fiber cohesion and overall material reliability.
Solution Approach 2:
The patent changes the matrix composition parameters by defining specific weight percentage ranges for silicon carbide (30-70 wt%) and crystalline silica (30-70 wt%). This parameter control optimizes the balance between achieving sufficient silicon infiltration for fiber cohesion while preventing harmful segregation through the stabilizing presence of crystalline silica in controlled amounts.
3Strength
If carbon-ceramic composite materials are used for brake disks, then mechanical properties are improved, but oxidation resistance is insufficient leading to carbon loss and surface cavities
Solution Approach 1:
The patent applies composite materials by creating a ceramic matrix of silicon carbide and crystalline silica that encapsulates the carbon fibers. This composite structure maintains the excellent mechanical properties provided by the carbon fiber reinforcement while the oxidization-resistant ceramic matrix protects the carbon from oxidation, preventing carbon loss and surface cavity formation in high-temperature oxidative environments.
Solution Approach 2:
The patent changes the chemical composition parameters by incorporating silicon carbide (30-70 wt%) and crystalline silica (30-70 wt%) into the matrix. This compositional modification provides oxidation resistance to the carbon fibers while preserving the mechanical strength, thereby resolving the contradiction between mechanical properties and oxidation resistance in brake disk applications.
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 results in improved mechanical and thermal properties, increased toughness, and reduced silicon segregation, enabling the production of composite ceramic materials suitable for high-temperature applications with extended service life and enhanced wear resistance.
Implementation Method 1
infiltrating said porous shaped body with molten silicon
Implementation Method 2
infiltration thereof into the pores of the aforesaid semi-finished product
Implementation Method 3
molten silicon, under the conditions of the second baking, reacts partly with the carbon of the semi-finished product thereby forming silicon carbides
Implementation Method 4
subjecting said green body to pyrolysis to produce a porous shaped body
Data Source
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AI summary
The invention relates to a method for making a composite ceramic material, comprising the following operating steps: a) producing a green body from an aggregate of fibers, preferably carbon fibers, and a carbonaceous matrix; b) subjecting said green body to pyrolysis such as to produce a porous shaped body; c) optionally heat-treating said porous shaped body to cause at least partial graphitization of the carbon; d) infiltrating said porous shaped body with molten silicon, obtaining a body made of composite ceramic material. The composite ceramic body comprises one or more metals, selected from the group consisting of tin, zinc, iron, germanium, titanium, zirconium and manganese, and/or the compounds thereof, selected from the group consisting of carbides, silicides, borides, nitrides, MAXPhase. Said one or more metals and/or the compounds thereof are introduced: in step a) the production of the green body as additives to the fibers and to a resin that forms the carbonaceous matrix; and/or in the porous shaped body before step d) of infiltration with silicon by physical and chemical infiltration processes; and/or in step d) of infiltration with silicon mixed with molten silicon.