Silicon Carbide Honeycomb Structure for Rapid Thermal Response
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Solution Overview
Problem
Honeycomb structures used in exhaust systems face challenges with high heat capacity and poor temperature-rising properties, making it difficult to follow ambient temperature changes rapidly, which affects their performance as filters and catalyst carriers.
Innovation Solution
A honeycomb structure with a porous partition wall formed by a silicon phase as the main phase, containing metals like Fe, Ca, Al, Ti, and Zr in limited amounts, and incorporating oxides such as SiO2, with specific microstructure characteristics to achieve low heat capacity and high thermal diffusivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional honeycomb structures with refractory particles and metallic silicon are used, then structural strength is maintained, but heat capacity becomes high and thermal diffusivity becomes low
Solution Approach 1:
The invention changes the material composition parameters by using silicon carbide particles with specific purity (95-99.9 mass%) and controlling the bonding agent content (5-20 mass% of total weight), thereby achieving low heat capacity and high thermal diffusivity while maintaining structural integrity
Solution Approach 2:
The invention creates a composite material system combining silicon carbide particles as aggregate with silicon or silicon-based compound bonding agents, forming a honeycomb structure that achieves both mechanical strength and superior thermal response characteristics
2Speed
If conventional honeycomb structures are used, then structural integrity is maintained, but the structure cannot follow ambient temperature changes rapidly
Solution Approach 1:
The invention optimizes physical parameters including porosity (30-70%), cell density (10-100 cells/cm²), and wall thickness (0.2-1.0 mm) to achieve rapid temperature response while maintaining structural stability and thermal diffusivity
3Strength
If silicon components are covalently bonded with high silicon content, then bonding strength is improved, but thermal diffusivity decreases
Solution Approach 1:
The invention applies local quality by using silicon-based compounds (oxides, nitrides, carbides) as bonding agents instead of pure silicon, creating localized bonding zones that provide sufficient strength while maintaining overall thermal diffusivity of the structure
Solution Approach 2:
The invention changes the bonding mechanism from metallic silicon bonding to silicon-based compound bonding, controlling the bonding agent content at 5-20 mass% to achieve optimal balance between bonding strength and thermal diffusivity
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 improved temperature-rising properties, allowing it to follow ambient temperature changes rapidly, reducing regeneration frequency, and enhancing thermal shock resistance, while maintaining strength and trapping efficiency.
Implementation Method 1
a porous sintered body which contains silicon as a main component where silicon components are covalently bonded
Implementation Method 2
high thermal diffusivity and that follows the ambient temperature change rapidly
Data Source
AI summary
A honeycomb structure includes a pillar-shaped honeycomb structure body having a porous partition wall. The honeycomb structure body includes a plurality of cells defined by the partition wall so as to extend from a first end face to a second end face of the honeycomb structure body, the partition wall is formed by a porous body including a silicon phase as a main phase, and the silicon phase as the main phase has content of each of metals other than silicon and metals making up silicide that is 0.3 part by mass or less with respect to 100 parts by mass of silicon.