Honeycomb Structure Thermal Stability via Tabular Grain Orientation
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Solution Overview
Problem
Honeycomb structures used for cleaning exhaust gases require enhanced thermal stability to withstand heat-related expansion and shrinkage, which is not adequately addressed by existing methods that prioritize formability over thermal stability.
Innovation Solution
A method and apparatus for manufacturing honeycomb structures using a three-dimensional shaping process, where tabular grains are arranged in a predetermined direction to enhance thermal stability, specifically by using cordierite with kaolin and talc as raw materials and sintering them to control thermal expansion coefficients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If hydrophilic talc is used to improve fluidity and extrusion speed, then formability is enhanced, but thermal stability is not sufficiently taken into consideration
Solution Approach 1:
The invention changes the physical and chemical parameters of the raw materials by specifying precise compositional ranges (e.g., SiO2: 40-70 wt%, Al2O3: 15-30 wt%, MgO: 5-15 wt%) and controlling the tabular grain-to-spherical grain ratio (0.3-2.0). These parameter adjustments optimize both formability during extrusion and thermal stability during firing, resolving the contradiction between ease of manufacture and reliability.
Solution Approach 2:
The invention uses a composite raw material system combining multiple components: tabular grains (providing thermal stability), spherical grains (improving fluidity), organic binder (enabling shaping), and water (aiding extrusion). This composite approach allows each component to contribute its strengths, achieving both good formability and high thermal stability simultaneously.
2Reliability
If tabular grains are arranged in a predetermined direction using a three-dimensional shaping apparatus, then thermal stability is enhanced, but manufacturing process complexity increases
Solution Approach 1:
The invention applies preliminary action by pre-arranging tabular grains in a predetermined direction (with flat surfaces oriented at 0°-30° relative to the extrusion direction) before the sintering process. This pre-arrangement ensures that crystal grains will grow in the desired orientation during firing, achieving thermal stability without requiring complex real-time control during manufacturing.
Solution Approach 2:
The invention applies local quality by specifically orienting tabular grains in the partition thickness direction (with flat surfaces at predetermined angles), while other materials and processes remain conventional. This localized optimization of grain orientation provides thermal stability enhancement without requiring complete redesign of the entire manufacturing system.
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 approach significantly improves thermal stability and thermal shock resistance of the honeycomb structures, allowing them to perform better under heat cycles and reducing the risk of breakage and cracking.
Implementation Method 1
tabular grains are arranged in a predetermined direction with respect to the partition surfaces while the tabular grains and the raw material grains constitute a raw material for forming the partitions
Implementation Method 2
a sintering step of sintering the placed raw material
Implementation Method 3
crystal grains constituting the partition may grow during firing depending on the direction of the crystal axis of the tabular grains
Implementation Method 4
cordierite crystal grains may be generated by firing
Data Source
AI summary
A method for manufacturing a honeycomb structure according to the present invention is a method for manufacturing a honeycomb structure provided with partitions forming a plurality of cells. This manufacturing method includes a structure formation process including a pore-forming material placement step of placing a pore-forming material for forming pores in the partitions, a raw material placement step of placing tabular grains and raw material grains such that the tabular grains are arranged in a predetermined direction with respect to the partition surfaces while the tabular grains and the raw material grains constitute a raw material for forming the partitions, and a sintering step of sintering the placed raw material. The honeycomb structure is produced by repeating the structure formation process a plurality of times.