Honeycomb Structure Bonding Material Composition
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Solution Overview
Problem
Honeycomb structures used in high-temperature environments face challenges with insufficient wettability of metal silicon, leading to low strength and thermal conductivity, which results in damage due to thermal stress and excessive temperature during regeneration, and high thermal expansion coefficients.
Innovation Solution
A honeycomb structure with a porous body having refractory aggregates and a bonding material comprising metal Si and an oxide material, with a porosity of 25-70% and a bonding material ratio of 30-50%, and an oxide material ratio of 30-80%, enhancing heat capacity and thermal conductivity while maintaining structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal silicon is used as bonding material between silicon carbide particles, then wettability improves, but thermal conductivity remains insufficient and strength is not sufficiently obtained
Solution Approach 1:
The bonding material is formulated as a composite comprising metal silicon (30-70 mass%) and oxide material (30-70 mass%). This composite structure combines the high wettability and bonding capability of metal silicon with the high thermal conductivity and thermal stability of oxide materials, simultaneously improving both strength and thermal conductivity while maintaining wettability between silicon carbide particles.
2Strength
If firing temperature is increased to improve bonding, then strength improves, but thermal stress damage increases and yield decreases
Solution Approach 1:
The invention changes the compositional parameters of the bonding material by incorporating oxide materials with high melting points and low thermal expansion coefficients. This allows the bonding material to maintain structural integrity and bonding capability at reduced firing temperatures (1000-1500°C), thereby achieving sufficient strength while minimizing thermal stress damage and improving yield.
3Object-generated harmful factors
If porosity is increased to improve pressure loss characteristics, then pressure loss decreases, but thermal conductivity decreases and strength is reduced
Solution Approach 1:
The invention applies local quality by using oxide materials with inherently high thermal conductivity in the bonding material phase. This allows the porous body to maintain adequate thermal conductivity despite increased porosity, as the oxide-rich bonding material creates thermal conduction pathways between silicon carbide particles, simultaneously achieving lower pressure loss and maintained thermal conductivity.
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 achieves high strength and thermal conductivity, preventing damage from thermal stress and maintaining lower maximum temperatures during regeneration, while minimizing pressure loss and ensuring effective particulate matter trapping.
Implementation Method 1
forming this material into a desirable shape and drying the material, followed by firing in a temperature range of 1600 to 2200° C.
Implementation Method 2
a heat capacity of the honeycomb structure is large, and hence when particulate matter deposited in a filter (the honeycomb structure) is burnt to regenerate the filter, a temperature of the filter excessively heightens sometimes
Implementation Method 3
a thermal conductivity of the honeycomb structure is large, and hence when the temperature of the filter heightens during the regeneration of the filter, the filter is damaged due to large thermal stress generated in the filter
Data Source
AI summary
A honeycomb structure including a pillar-shaped honeycomb structure body having partition walls defining a plurality of cells which become through channels for a fluid and extend from a first end face to a second end face, the partition walls include a porous body having refractory aggregates and a bonding material which bonds the refractory aggregates to each other, the bonding material includes metal Si and an oxide material, porosity of the porous body constituting the partition walls is 25% or more and 70% or less, a ratio of a mass of the bonding material to a mass of the whole porous body is 30 mass % or more and 50 mass % or less, and a ratio of a mass of the oxide material to the mass of the bonding material is 30 mass % or more and 80 mass % or less.