Composite Ceramic Substrates for Thermal Expansion Control
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Solution Overview
Problem
Existing ceramic materials for catalytic substrates and particulate filters often lack optimal thermal expansion properties and domain structures, which can lead to performance issues in varying temperature environments.
Innovation Solution
A composite ceramic material comprising a first refractory phase with a high melting point and a second refractory phase with a lower melting point, where the second phase has domain sizes greater than 5,000 μm2, is developed, along with a method of manufacturing that involves heating a mixture of refractory material precursors to form a composite ceramic material with specific domain structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-phase ceramic material is used, then the manufacturing process is simple, but the thermal expansion properties are not optimal and micro-stress/microcracking occurs in high-temperature environments
Solution Approach 1:
The patent applies composite materials by combining two distinct crystalline phases (first refractory material and second refractory material with lower melting point) to create a composite ceramic material. This composite structure resolves the technical contradiction by providing optimal thermal expansion properties through the synergistic interaction of phases, while preventing micro-stress and microcracking that occur in single-phase materials during thermal cycling.
2Reliability
If the second refractory material phase is added to form a composite, then thermal expansion properties improve, but the manufacturing process becomes more complex
Solution Approach 1:
The patent applies parameter changes by carefully controlling the domain size of the second crystalline phase to be greater than 5,000 μm² and adjusting the volume ratio between phases. These parameter optimizations improve thermal expansion properties while managing manufacturing complexity through defined compositional ranges and processing conditions that achieve desired properties without excessive process complexity.
3Reliability
If large domain sizes of the second refractory material are achieved, then thermal expansion properties and resistance to microcracking improve, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies parameter changes by specifying that the second crystalline phase domain size must be greater than 5,000 μm² and controlling the volume ratio of phases. These parameter definitions provide clear manufacturing targets that balance the need for large domains (to reduce microcracking) with achievable manufacturing precision through controlled processing conditions and compositional ranges.
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 composite ceramic material exhibits improved thermal expansion properties, such as lower coefficient of thermal expansion (CTE), which enhances its performance in high-temperature applications by reducing micro-stress and microcracking, and achieving desired physical properties like low CTE and high porosity.
Implementation Method 1
the heating is sufficient to cause at least some of the first refractory material to melt and to contact at least some of the second refractory material without causing the second refractory material to melt during the heating
Data Source
AI summary
Composite ceramic materials are disclosed herein which comprise two or more crystalline phases, wherein a first crystalline phase comprises a first refractory material having a first melting point, and a second crystalline phase comprises a second refractory material having a second melting point which is lower than the first melting point, and the second crystalline phase comprises large domain sizes of the second refractory material. Articles comprising such a composite ceramic material, such as honeycomb bodies, catalytic substrates, and particulate filters, are also disclosed herein, in addition to methods of manufacture thereof.