Honeycomb Structure Manufacturing Using Ion-Exchanged Smectite Binder
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Solution Overview
Problem
Existing manufacturing methods for ceramic honeycomb structures face challenges in inhibiting defects like cracks due to temperature and shrinkage differences during degreasing or firing, and they often compromise on thermal shock resistance and environmental impact.
Innovation Solution
A manufacturing method using a forming raw material with ion-exchanged smectite as an inorganic binder, where interlayer metal cations are exchanged with non-metal cations, specifically ammonium ions, to control sodium content and improve thermal shock resistance, while minimizing organic binder usage and reducing CO2 emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a large amount of organic binder is added to improve formability of large-sized honeycomb structures, then formability improves, but mechanical strength deteriorates and defects such as cracks are easily generated during firing
Solution Approach 1:
The patent changes the chemical composition parameters of the binder system by limiting organic binder to 3 mass% or less and introducing specific inorganic binder components (alumina 70-90 mass%, silica 5-20 mass%, magnesia 0-5 mass%) with controlled particle size distributions (D10, D50, D90 values), thereby achieving both formability and mechanical strength
Solution Approach 2:
The patent creates a composite binder system combining organic binder (3 mass% or less) with a specifically formulated inorganic binder mixture containing alumina, silica, and magnesia in controlled proportions and particle size distributions, replacing pure organic binder to eliminate its harmful effects during firing while maintaining formability
2Ease of manufacture
If a large amount of organic binder is used in large-sized honeycomb structures, then formability improves, but thermal stress from temperature difference between inner and outer portions increases, generating defects such as cracks
Solution Approach 1:
The patent changes the binder composition parameters by severely limiting organic binder content to 3 mass% or less and specifying inorganic binder composition with controlled particle size distributions, thereby reducing burning heat and thermal stress while maintaining formability through inorganic binder plasticity
Solution Approach 2:
The patent converts the potential harm of reduced organic binder (which provides plasticity) into a benefit by replacing it with a specifically formulated inorganic binder system that provides both plasticity and thermal stability, eliminating the thermal stress problem while maintaining formability
3Loss of substance
If organic binder is burned during firing to remove it, then the binder is eliminated, but CO2 and toxic gases are generated causing environmental pollution
Solution Approach 1:
The patent changes the chemical composition parameters by limiting organic binder to 3 mass% or less and replacing it with inorganic binder components (alumina, silica, magnesia) that do not produce toxic gases during heating, thereby achieving binder removal without environmental pollution
Solution Approach 2:
The patent converts the harmful organic binder that produces toxic gases into a beneficial inorganic binder system that provides the necessary binding function during forming while being environmentally benign during the firing process, eliminating toxic emissions
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 method effectively inhibits crack generation and enhances thermal shock resistance, reducing environmental pollution by minimizing toxic gas emissions during firing.
Implementation Method 1
smectite in which at least parts of interlayer metal cations are ion-exchanged with non-metal cations
Data Source
AI summary
A manufacturing method of a honeycomb structure includes a forming step of preparing a forming raw material containing a cordierite forming material and an inorganic binder, and kneading and forming the prepared forming raw material to have a honeycomb shape; and a firing step of firing the prepared formed body. In the forming step, as the inorganic binder, smectite is used in which at least parts of interlayer metal cations are ion-exchanged with non-metal cations. In the smectite, a total amount of sodium to be contained in the smectite is 1.6 mass % or less in terms of oxides to 100 mass % of the smectite. A content ratio of the smectite in the forming raw material is 0.5 parts by mass or more and 4.0 parts by mass or less to 100 parts by mass of the cordierite forming material.