Green Cellular Ceramic Body Polymer Barrier for Solvent Processing
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Solution Overview
Problem
Current methods for manufacturing ceramic articles with varying web properties along or across the honeycomb structure are economically unviable and result in thermal stresses and lower permeability due to the need for additional thermal treatment steps and separate pore structures, which are not continuous.
Innovation Solution
A method involving treating a green cellular ceramic body with a fluid to deposit a polymer thin layer, followed by post-processing with a solvent-resistant composition, allowing for the formation of a polymer barrier that protects the binder and enables subsequent processing without solubilization, thereby allowing for the creation of ceramic articles with tailored porosity and pore size variations in a single firing step.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If additional thermal treatment steps are used to create ceramic articles with varying web properties, then the porosity and pore size distribution can be tailored, but thermal stresses increase and manufacturing complexity increases
Solution Approach 1:
The patent applies a coating composition to the green (unfired) ceramic body before the main firing step, preliminary establishing the desired porosity variation in the web structure. This allows the porous structure to be formed during the single main firing rather than requiring additional thermal treatment steps afterward, thereby reducing thermal stress accumulation.
Solution Approach 2:
The patent combines the formation of the porous web structure and the final ceramic sintering into a single firing step. By integrating these processes, the patent eliminates multiple thermal cycles that would otherwise generate cumulative thermal stresses, while still achieving the desired varying porosity distribution.
2Manufacturing precision
If additional thermal treatment steps are used to create ceramic articles with varying web properties, then the porosity and pore size distribution can be tailored, but manufacturing complexity and costs increase
Solution Approach 1:
The coating composition is applied to the green body before the main firing, preliminarily configuring the web structure with desired porosity variations. This preliminary action allows the complex porous structure to be established in advance, eliminating the need for additional thermal treatment steps and simplifying the overall manufacturing process.
Solution Approach 2:
The patent modifies the properties of the green ceramic body by applying a coating composition that changes the local composition and structure. This parameter change in the green state allows for subsequent formation of varying porosity during a single firing step, reducing manufacturing complexity compared to multiple thermal treatments.
3Ease of manufacture
If the binder material is soluble in the processing solvent, then the green cellular ceramic body can be processed, but the binder solubilizes and compromises the structural integrity
Solution Approach 1:
The patent introduces a coating composition as an intermediary layer between the solvent-based processing fluid and the binder material in the green ceramic body. This coating acts as a barrier that prevents the solvent from directly contacting and solubilizing the binder, thereby maintaining structural integrity while still allowing necessary processing to occur.
Solution Approach 2:
The coating composition is applied in advance to counteract the harmful effect of solvent-binder interaction. By establishing this protective layer before processing, the patent preemptively prevents the binder from solubilizing, thus preserving the green body's structural integrity during subsequent processing steps.
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 enables the production of ceramic articles with optimized porosity and pore size variations, reducing thermal stresses and increasing permeability while simplifying the manufacturing process and reducing costs by eliminating the need for multiple firing steps.
Implementation Method 1
the polymer layer forms a barrier to at least partially protect the binder from the liquid vehicle
Implementation Method 2
firing the green cellular ceramic body to a temperature sufficient to fire the ceramic precursor composition
Data Source
Figure 1
Figure 2A~2C
Figure 2D
AI summary
A method and apparatus to treat a dried unfired article comprising a ceramic precursor composition substantially held together by a binder, to be resistant to binder soluble solvent based processing. The method includes depositing a fluid on the article surface, and polymerizing the deposited fluid to form a polymer thin layer on the surface. The fluid may be an aerosol, a vapor, a fog, a mist, a smoke, or combinations thereof. An apparatus to perform the method and an article resistant to binder soluble solvent based processing are also provided. The article can be an unfired honeycomb body that includes a dried composition of ceramic precursor substantially held together by a binder and a layer disposed on a surface of the unfired honeycomb body. The surface to be exposed in the green state to a binder soluble solvent and the layer protects the binder from solubilization by the solvent.