Ceramic Honeycomb Outer Wall Coating Crack Prevention
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Solution Overview
Problem
Ceramic honeycomb structures used for exhaust gas purification and particulate filtration face issues with mechanical strength due to thin partition walls and high porosity, leading to crack formation and catalyst leakage during the coating process, which complicates the manufacturing process and requires manual amendment operations.
Innovation Solution
A method involving a coating material with a ceramic powder aggregate having a specific particle size distribution, characterized by a single peak in the particle size distribution curve and a defined average particle size of 23 to 39 μm, and a particle size distribution width of 15 to 33, applied and heat-dried to form a robust outer wall, reducing crack generation and eliminating the need for manual amendment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If natural drying is performed at ordinary temperature, then crack generation is suppressed, but drying time becomes excessively long (24 hours or more)
Solution Approach 1:
The patent changes the particle size distribution parameters of the ceramic powder, specifically controlling the distribution width to be within a certain range. This parameter adjustment allows the coating material to undergo controlled contraction during drying, enabling faster drying times while preventing crack formation through optimized physical properties of the powder aggregate.
2Productivity
If heat-drying is performed to reduce drying time, then productivity improves, but crack generation increases
Solution Approach 1:
The patent adjusts the particle size distribution width parameter of the ceramic powder to a specific range, which controls the contraction characteristics of the coating material during heat-drying. This enables the use of heat-drying for faster processing while the controlled particle size distribution prevents excessive contraction stresses that would cause cracking.
3Manufacturing precision
If manual amendment operation is performed to fix cracks, then coating quality improves, but manufacturing complexity and time increase
Solution Approach 1:
The patent performs preliminary action by pre-adjusting the particle size distribution of the ceramic powder within the optimal range before applying the coating material. This preliminary preparation ensures that the coating material has controlled contraction characteristics from the outset, preventing crack formation during drying and eliminating the need for subsequent manual amendment operations, thereby simplifying the manufacturing process.
4Ease of operation
If ceramic powder with large average particle size is used, then coating material流动性 improves, but drying contraction increases causing cracks
Solution Approach 1:
The patent changes the particle size distribution width parameter while maintaining a relatively large average particle size. By controlling the distribution width within a specific range, the patent achieves a balance where the coating material maintains good flowability due to the large particles while the controlled distribution prevents excessive drying contraction, thereby avoiding crack formation.
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 enhances the mechanical strength of the ceramic honeycomb structure, prevents crack formation and peeling, and significantly reduces the drying time, thereby improving manufacturing efficiency and productivity.
Implementation Method 1
a coating material heat-drying step for forming an outer wall by heat-drying the coating material after the coating material application step
Implementation Method 2
a crack is caused due to a contraction difference between the surface and the inside of the coating material
Data Source
AI summary
There is provided a method for manufacturing a ceramic honeycomb structure comprising: a coating material adjustment step for obtaining a coating material by mixing at least water with a ceramic powder aggregate having only one peak in a particle size distribution, an average particle size of 23 to 39 μm, and a particle size distribution width of 15 to 33, a coating material application step for applying the coating material to cover the outer periphery of a honeycomb structure having a plurality of cells separated by porous ceramic partition walls, and a coating material heat-drying step for forming an outer wall by heat-drying the coating material after the coating material application step. By the method, the outer periphery is covered with a coating material to form an outer wall to hardly generate, for example, crack generation and peeling upon drying the outer wall, and the coating material is provided.