Silicon Carbide Honeycomb Structure Manufacturing

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Solution Overview

Problem

Conventional methods for manufacturing high-porosity silicon carbide honeycomb structured bodies struggle with maintaining form during the degreasing process, making it difficult to transfer degreased molded bodies, especially at larger scales.

Innovation Solution

Incorporating a silicon carbide precursor that converts into silicon carbide at a temperature higher than the degreasing temperature, acting as a binder to maintain the structure and allowing for machine transfer, and optimizing the ratio and proportions of silicon carbide and pore-forming material particles to achieve high porosity and strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a high proportion of pore-forming material is used to achieve high porosity, then the porosity increases, but the degreased molded body becomes prone to deformation and difficult to transfer

Engineering Contradiction:
ImproveporosityVSAvoidstructural strength
Core Design Contradiction:
Quantity of substanceVSStrength

Solution Approach 1:

The invention uses a composite material system consisting of silicon carbide particles, pore-forming material particles, and a silicon carbide precursor. The precursor acts as a binding phase that holds the structure together during degreasing, while the pore-forming material creates porosity. This composite approach allows achieving high porosity (70-90%) while maintaining structural strength for easy transfer.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention changes the chemical state of the binding material by using a silicon carbide precursor that converts to silicon carbide at high temperature. During degreasing, the precursor remains in its original state providing binding strength, while after degreasing it can be converted. This parameter change allows the material to provide strength when needed and then transform to achieve the desired porosity.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If the porosity is increased to support more catalyst, then the filter performance improves, but the molded body becomes more fragile during degreasing

Engineering Contradiction:
Improvecatalyst capacityVSAvoidhandling reliability
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The invention performs preliminary action by adding a silicon carbide precursor to the molded body before degreasing. This precursor acts as a temporary reinforcement that prevents deformation during the degreasing process. After degreasing completes successfully, the precursor can be converted or removed, leaving the desired high-porosity structure ready for catalyst support.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The silicon carbide precursor serves as an intermediary substance that mediates between the conflicting requirements of high porosity and handling strength. It provides the necessary structural support during the critical degreasing phase, enabling the process to complete successfully without deformation, and then allows the final high-porosity structure to be achieved for optimal catalyst capacity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Quantity of substance

If conventional manufacturing methods are used for high porosity bodies, then the porosity can be achieved, but machine transfer becomes very difficult

Engineering Contradiction:
ImproveporosityVSAvoidease of transfer
Core Design Contradiction:
Quantity of substanceVSEase of operation

Solution Approach 1:

The invention changes the physical and chemical parameters of the molded body by incorporating a silicon carbide precursor that maintains structural integrity during degreasing. This parameter change transforms the molded body from a fragile high-porosity structure into a temporarily reinforced structure that can withstand handling, enabling easy machine transfer while maintaining the desired porosity level.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite material system where silicon carbide particles, pore-forming material particles, and silicon carbide precursor work together. The precursor phase provides the mechanical strength needed for easy handling and transfer, while the pore-forming material ensures high porosity is achieved. This composite structure resolves the contradiction between porosity and ease of transfer.

Inventive Principle:
Principle #40Composite materials

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 enables the production of honeycomb structured bodies that can withstand external forces and are easily transferable, maintaining form and achieving high porosity, suitable for large-scale manufacturing and use as filters for exhaust gas purification.

Implementation Method 1

a silicon carbide precursor that is to be converted into silicon carbide at a temperature of higher than a degreasing temperature

Methodology Applied
Scientific EffectPhase transition: Phase Change

Implementation Method 2

a degreasing step of degreasing the honeycomb molded body into a honeycomb degreased body

Methodology Applied
Scientific EffectDegreasing:

Data Source

PatentEP2851170B1Method for manufacturing honeycomb structure
Publication Date: 2019.08.21 IBIDEN CO LTD
  • EP2851170B1 patent drawingFigure 1(a)~1(b)
  • EP2851170B1 patent drawingFigure 2~3
  • EP2851170B1 patent drawingFigure 4

AI summary

The method for manufacturing a honeycomb structured body of the present invention includes a honeycomb molded body preparing step of preparing a honeycomb molded body in which a large number of cells are longitudinally disposed in parallel with one another with a cell wall interposed therebetween; a degreasing step of degreasing the honeycomb molded body into a honeycomb degreased body; and a firing step of firing the honeycomb degreased body into a porous silicon carbide honeycomb fired body, wherein the honeycomb molded body containing silicon carbide particles, pore-forming material particles, and a silicon carbide precursor that is to be converted into silicon carbide at a temperature of higher than a degreasing temperature.