Bonding Material Layer for Honeycomb Structure Thermal Shock Resistance
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Solution Overview
Problem
Honeycomb structures used in diesel particulate filters face challenges with thermal shock resistance due to high thermal stress during regeneration, leading to potential cracks or ruptures, and existing bonding material layers with low Young's modulus provide insufficient bonding strength while high Young's modulus increases stress on the bonding material layer, making it prone to breakage.
Innovation Solution
A bonding material layer composed of flat particles, non-flat particles, and an inorganic adhesive with a Young's modulus of 3 GPa or more, where flat particles have a Young's modulus of 100 GPa or more, and are used at a specific ratio within the bonding material composition to enhance both thermal shock resistance and bonding strength, reducing deformation and rupture risk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bonding material layer has low Young's modulus, then thermal stress is lowered and thermal shock resistance is improved, but bonding strength between honeycomb segments becomes insufficient
Solution Approach 1:
The bonding material layer is formulated as a composite material containing inorganic adhesive (30-70 wt%), flat particles (10-50 wt%) with aspect ratio of 0.5 or more and average particle diameter of 1-200 μm, and non-flat particles (5-40 wt%). This composite structure allows the bonding material to simultaneously achieve low Young's modulus (reducing thermal stress) and high bonding strength (through the reinforcing effect of flat particles), resolving the contradiction between thermal shock resistance and bonding strength.
Solution Approach 2:
The invention optimizes specific parameters of the bonding material composition: the inorganic adhesive content is controlled at 30-70 wt% to balance flexibility and strength, flat particles are specified with aspect ratio of 0.5 or more and diameter of 1-200 μm to provide reinforcement without excessive rigidity, and porosity is maintained at 30-70% to reduce thermal stress while preserving bonding capability. These parameter optimizations enable the bonding material layer to achieve both low Young's modulus and sufficient bonding strength.
2Shape
If the bonding material layer has high Young's modulus, then deformation of honeycomb segments due to thermal distortion is suppressed, but stress applied on the bonding material layer increases causing it to break
Solution Approach 1:
The bonding material layer uses a composite formulation with inorganic adhesive as the base matrix providing flexibility and stress distribution, flat particles (aspect ratio ≥ 0.5, diameter 1-200 μm) as reinforcing agents that suppress deformation through their geometric constraints, and non-flat particles for additional structural support. This composite structure allows the bonding material to maintain shape stability under thermal distortion while the inorganic adhesive matrix and optimized porosity prevent stress concentration and breakage.
Solution Approach 2:
The bonding material layer is designed with controlled porosity of 30-70%, creating a porous structure that reduces the effective Young's modulus and allows for thermal expansion accommodation. The porous structure acts as a stress buffer, preventing stress concentration that would lead to breakage, while the flat particles within the porous matrix provide sufficient deformation suppression through their high aspect ratio geometry.
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 solution effectively suppresses deformation and rupture of the bonding material layer, achieving excellent thermal shock resistance and maintaining bonding strength, enabling the honeycomb structure to withstand thermal stress without cracking or breaking.
Implementation Method 1
a bonding material layer having a Young's modulus of 3 GPa or more, deformation of the honeycomb segments due to thermal distortion can be suppressed by the bonding material layer
Data Source
AI summary
There is provided a joined body formed by unitarily joining two or more members to be joined by means of a bonding material layer formed of a bonding material composition. The bonding material composition contains flat particles, non-flat particles, and an inorganic adhesive as main components, and the bonding material layer has a Young's modulus of 3 GPa or more. The joined body can suppress deformation of members to be joined due to thermal distortion with the bonding material layer, hardly causes rupture of the bonding material layer due to stress, and has excellent thermal shock resistance.