Ceramic Honeycomb Bonding Layer for Thermal Shock Resistance
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Solution Overview
Problem
Conventional ceramic honeycomb structures face issues with insufficient bonding material layer strength when subjected to thermal stress during regeneration, leading to potential failure such as cracking and breakage due to uneven heating, local heat generation, and heat shock from rapid temperature changes.
Innovation Solution
A ceramic honeycomb structure with honeycomb segments bonded via a bonding material layer comprising silicon carbide particles and a bonding phase of at least a cordierite and spinel phase, with a specific molar ratio and content, providing excellent thermal-stress-relaxing function and strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bonding material layer is used to bond honeycomb segments, then the thermal stress is alleviated, but the bonding material layer lacks sufficient strength under thermal stress during regeneration
Solution Approach 1:
The bonding material layer is formulated as a composite material containing silicon carbide particles (30-70 mass%), alumina particles (10-40 mass%), and magnesia particles (5-20 mass%). This multi-component composite provides both thermal stress resistance through the thermal conductivity of silicon carbide and sufficient mechanical strength through the combined properties of all constituents, resolving the contradiction between reliability and strength.
Solution Approach 2:
The invention optimizes the particle size distribution of the bonding material constituents, specifying that silicon carbide particles have an average particle diameter of 5-50 μm. This parameter control ensures proper packing density and bonding characteristics, achieving both adequate strength and thermal stress resistance by adjusting the physical parameters of the bonding material composition.
2Stability of the object's composition
If honeycomb segments are integrally bonded to form a ceramic honeycomb structure, then the structure can withstand thermal stress, but the bonding material layer may crack or break under severe thermal conditions
Solution Approach 1:
The bonding material layer uses a composite formulation with silicon carbide particles providing thermal conductivity and stress distribution, alumina particles contributing to mechanical strength, and magnesia particles enhancing refractory properties. This composite structure prevents cracking and breakage under severe thermal conditions while maintaining integral bonding of honeycomb segments.
Solution Approach 2:
The bonding material layer is designed with specific local properties at the interfaces between honeycomb segments, where the concentrated silicon carbide particles create zones of enhanced thermal conductivity and stress tolerance. This local quality enhancement prevents crack propagation at critical bonding locations, maintaining overall structural integrity.
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 structure exhibits enhanced thermal-stress-relaxing function and strength, comparable to or exceeding conventional structures, effectively alleviating stress concentration and maintaining integrity under thermal stress conditions.
Implementation Method 1
a bonding material layer bonding the peripheral walls of the honeycomb segments, the bonding material layer comprising silicon carbide particles as aggregate and a bonding phase bonding the silicon carbide particles
Implementation Method 2
the bonding phase comprising at least a cordierite phase and a spinel phase... exhibiting excellent thermal-stress-relaxing function
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3(a)~3(b)
AI summary
A ceramic honeycomb structure comprising pluralities of honeycomb segments each having pluralities of longitudinally penetrating flow paths partitioned by porous cell walls and plugs formed in the end portions of the flow paths, and a bonding material layer boding the peripheral walls of the honeycomb segments, the bonding material layer comprising silicon carbide particles as aggregate and a bonding phase bonding the silicon carbide particles, the bonding phase comprising at least a cordierite phase and a spinel phase, the molar ratio M1 of the cordierite phase [= cordierite phase/(cordierite phase + spinel phase)] being 0.50 or more and less than 1.0, and the content of (cordierite phase + spinel phase) in the bonding phase being 50% or more by mass.