Ceramic Composite Matrix Formation Without Heat-Treatment Cracks
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Solution Overview
Problem
The heat treatment process used to improve the heat resistance of ceramic-based composite materials formed by film boiling often results in matrix shrinkage and crack formation, necessitating an additional heat treatment step that is undesirable.
Innovation Solution
A method involving repeated heating of reinforcing fibers in a liquid material to specific temperatures, where the heat resistance imparting temperature exceeds the matrix forming temperature, eliminates the need for additional heat treatment and suppresses crack formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If heat treatment is performed at high temperature to improve heat resistance, then heat resistance is improved, but matrix volume shrinks causing cracks to form
Solution Approach 1:
The heat treatment process is segmented into multiple stages with different temperature ranges. The first heat treatment forms the matrix at a lower temperature, while the second heat treatment at a higher temperature improves heat resistance. This segmentation allows the matrix to form before the high-temperature treatment that causes shrinkage, thereby reducing crack formation while achieving the desired heat resistance.
Solution Approach 2:
The matrix formation is performed as a preliminary action before the heat resistance improvement treatment. By forming the matrix structure first through initial heat treatment, the subsequent high-temperature treatment can improve heat resistance without causing the matrix to form during the shrinkage-prone phase, thus preventing crack formation.
2Temperature
If additional heat treatment is performed after film boiling to improve heat resistance, then heat resistance is improved, but process complexity increases
Solution Approach 1:
The matrix formation process and heat resistance improvement process are merged into a single integrated heat treatment operation. By performing both functions in one continuous process rather than separate steps, the overall process complexity is reduced while still achieving both matrix formation and heat resistance improvement.
Solution Approach 2:
The heat treatment process is designed to serve multiple functions: it forms the matrix structure and simultaneously imparts heat resistance. This multi-functionality eliminates the need for separate additional heat treatment steps, thereby simplifying the overall manufacturing process while achieving the desired material properties.
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 produces a ceramic-based composite material with enhanced heat resistance without additional heat treatment, maintaining a low penetrating crack ratio and ensuring structural integrity.
Implementation Method 1
One of methods for forming the matrix in the ceramic-based composite material is film boiling (FB). In the film boiling, for example, the matrix can be formed as follows. The reinforcing fibers are disposed in a liquid material (e.g., liquid polycarbosilane: LPCS) of the matrix, and the reinforcing fibers are heated in this state. As a result, the matrix formed of LPCS precipitates to be formed on the reinforcing fibers.
Implementation Method 2
As a result, the matrix formed of LPCS precipitates to be formed on the reinforcing fibers.
Implementation Method 3
Next, a heat treatment is performed on the reinforcing fibers on which the matrix has been formed in a heating furnace for example, at a high temperature (e.g., a high temperature equal to or higher than 1200° C.). Thereby, the heat resistance of the matrix is improved.
Data Source
AI summary
To provide an innovative technique of producing a ceramic-based composite material including a matrix that has a heat resistance and in which formation of cracks is suppressed. A method for producing a ceramic-based composite material including a matrix and reinforcing fibers provided in the matrix includes disposing the reinforcing fibers in a liquid material for the matrix (step S2), heating the reinforcing fibers in the liquid material such that a temperature of the reinforcing fibers becomes a matrix forming temperature (step S31), and heating the reinforcing fibers in the liquid material such that a temperature of the reinforcing fibers becomes a heat resistance imparting temperature (step S32). The heat resistance imparting temperature is higher than the matrix forming temperature. The step S31 and the step S32 are repeated.