Honeycomb Structure Bonding Layer Conductivity
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Solution Overview
Problem
Existing honeycomb structures used as catalyst carriers for exhaust gas purification face challenges in achieving uniform heat generation due to varying electrical resistance values in the bonding layer, leading to potential breakdown and reduced thermal shock resistance.
Innovation Solution
A honeycomb structure with a bonding layer made of conductive inorganic fibers and metal silicide, where the volume resistivity of the bonding layer is controlled between 2 to 2000 Ωcm, and the bonding layer includes β-SiC fibers and silicon carbide particles bound with silicon, enhancing the structural integrity and heat distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the bonding layer is made conductive to enable uniform heat generation, then the electrical resistance decreases and heat distribution improves, but the bonding layer becomes more susceptible to breakdown under stress
Solution Approach 1:
The bonding layer is constructed as a composite material containing conductive inorganic fibers (such as β-SiC fibers) dispersed in a bonding matrix. This composite structure provides both electrical conductivity for uniform heat generation and mechanical strength to prevent breakdown under stress, resolving the contradiction between conductivity and reliability.
2Manufacturing precision
If the volume resistivity of the bonding layer is reduced to improve current flow, then heat generation uniformity improves, but the bonding layer strength decreases making it more prone to breakage
Solution Approach 1:
The bonding layer uses a composite formulation where conductive inorganic fibers provide electrical pathways for low resistance and uniform heat generation, while the bonding matrix maintains structural integrity and strength, simultaneously achieving both low volume resistivity and high strength.
Solution Approach 2:
The bonding layer exhibits local quality differentiation where conductive inorganic fibers are distributed to provide electrical conductivity in specific regions, while the bonding matrix provides structural support, allowing different parts of the bonding layer to fulfill different functions (conduction vs. strength).
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 honeycomb structure effectively maintains low electrical resistance, prevents bonding layer breakdown, and ensures uniform heat generation across the structure, while also providing superior thermal shock resistance.
Implementation Method 1
a honeycomb structure capable of being used as a catalyst carrier, which functions as a heater by applying a voltage
Implementation Method 2
the bonding layer is made of conductive inorganic fibers and metal silicide, where the volume resistivity of the bonding layer is controlled between 2 to 2000 Ωcm
Implementation Method 3
provides superior thermal shock resistance
Data Source
AI summary
To provide a honeycomb structure capable of using as a catalyst carrier, which functions as a heater, and where a bonding layer is hard to break and an electrical resistance value is hard to rise; including a honeycomb segment bonded body where honeycomb segments are bonded by bonding layer, and a pair of electrode members disposed on a side surface of the bonded body, the electrode members is formed into a band shape, and in a cross section perpendicular to the cell extending direction, one electrode member is disposed on an opposite side across the center of the bonded body to another electrode member, and in at least a part of the bonding layer, inorganic fibers made of β-SiC and a metal silicide are included in a porous body where silicon carbide are bound with silicon in a state where pores are held among the particles.