Ceramic Honeycomb Degreasing via Segmented Oxygen Control
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Solution Overview
Problem
Existing methods for manufacturing ceramic honeycomb structures face challenges in efficiently removing organic ingredients without causing thermal decomposition or oxidation issues, leading to potential deformation or cracking during the degreasing process.
Innovation Solution
A method involving the preparation of a raw material paste by kneading inorganic particles and a binder, forming a honeycomb structure, and then degreasing in two stages: first at an oxygen concentration of 0.2% or less to decompose organics thermally, followed by a higher oxygen concentration to oxidize remaining organics, before sintering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If organic ingredients are removed by heating in a conventional atmosphere, then degreasing is achieved, but thermal decomposition and oxidation cause deformation or cracking
Solution Approach 1:
The degreasing process is divided into multiple stages with progressively increasing oxygen concentration. The first stage uses low oxygen concentration (0.2-2.0%) to remove volatile organic components through thermal decomposition, while subsequent stages gradually increase oxygen concentration to oxidize remaining organics. This segmented approach prevents sudden thermal shock and structural deformation that would occur with conventional single-stage high-temperature heating.
Solution Approach 2:
Before the main oxidation phase, the patent performs preliminary thermal decomposition at low oxygen concentration to remove the most volatile and potentially harmful organic components. This preliminary action prepares the structure for subsequent oxidation without subjecting it to the full thermal stress immediately, thereby preventing deformation and cracking.
2Productivity
If heating temperature and time are increased to remove organics, then degreasing efficiency is improved, but thermal shock and deformation risk increase
Solution Approach 1:
The degreasing process is divided into multiple stages with progressively increasing oxygen concentration. The first stage uses low oxygen concentration (0.2-2.0%) to remove volatile organic components through thermal decomposition, while subsequent stages gradually increase oxygen concentration to oxidize remaining organics. This segmented approach prevents sudden thermal shock and structural deformation that would occur with conventional single-stage high-temperature heating.
Solution Approach 2:
The patent systematically changes atmospheric parameters (oxygen concentration) and thermal parameters (heating rate, holding temperature) across different stages. By controlling oxygen concentration at 0.2-2.0% in the first stage and gradually increasing it in subsequent stages, while also controlling heating rates, the process achieves efficient organic removal without causing thermal shock or deformation.
3Loss of time
If oxygen concentration is increased to oxidize organics faster, then degreasing time is reduced, but thermal decomposition and oxidation damage increase
Solution Approach 1:
The degreasing process is divided into multiple stages with progressively increasing oxygen concentration. The first stage uses low oxygen concentration (0.2-2.0%) to remove volatile organic components through thermal decomposition, while subsequent stages gradually increase oxygen concentration to oxidize remaining organics. This segmented approach prevents sudden thermal shock and structural deformation that would occur with conventional single-stage high-temperature heating.
Solution Approach 2:
The patent maintains continuous heating throughout the degreasing process while systematically adjusting oxygen concentration. This continuous thermal action ensures that organics are consistently removed across all stages, preventing any pause that would require re-heating and extending total process time. The continuous action combined with progressive oxygen increase optimizes both speed and safety.
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
This approach effectively removes organic ingredients in a shorter time, reduces the risk of thermal shock and deformation, and results in a stable ceramic honeycomb structure with improved mechanical properties.
Implementation Method 1
in a temperature range at which combustible gas is generated by thermally decomposing organic matter
Implementation Method 2
combustible gas is generated by thermally decomposing organic matter
Data Source
AI summary
A method for manufacturing a ceramic honeycomb structure includes kneading inorganic particles and binder ingredient such that raw material paste including the inorganic particles and binder ingredient is prepared, forming a body made of the raw material paste and having a honeycomb structure such that the body has the honeycomb structure having multiple through-holes extending in the longitudinal direction of the body and multiple partitions formed between the through-holes, degreasing of the body including heating the body in atmosphere maintaining oxygen concentration of 0.2% or less in the first heating and heating the body in atmosphere having oxygen concentration which is higher than the oxygen concentration of the first heating in the second heating such that a degreased body having the honeycomb structure is formed, and sintering the degreased body having the honeycomb structure such that a ceramic body having the honeycomb structure is formed.