Boron Nitride Setter Pore Control for Ceramic Firing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing setters formed using hexagonal boron nitride powder can lead to variations in ceramic plate quality, including insufficient sintering, strength issues, and color unevenness, due to impaired gas escape and sintering aid loss during firing.
Innovation Solution
A setter composed of a boron nitride sintered plate with a porosity of 8 vol% or higher and a proportion of pores with diameters between 0.2 to 0.9 µm, measured by mercury porosimetry, which facilitates gas escape and maintains airtightness during firing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a porous sintered body is used as a setter to enable gas escape during degreasing, then gas escape is facilitated, but airtightness during firing is compromised leading to sintering aid loss
Solution Approach 1:
The invention changes the pore diameter parameter to a specific range (0.2 to 0.9 μm) and controls porosity (8 vol% or higher) to achieve both gas escape during degreasing and airtightness during firing. This parameter optimization resolves the contradiction by finding the optimal pore size that allows low-temperature gas permeation while maintaining high-temperature airtightness.
Solution Approach 2:
The invention utilizes thermal expansion characteristics of the sintered body to close pores at high firing temperatures, transforming the porous structure into an airtight structure during firing. This thermal transformation resolves the contradiction between needing open pores for gas escape and closed pores for airtightness.
2Object-generated harmful factors
If pore diameters are large to facilitate gas escape, then gas escape is improved, but sintering aid escapes to the outside before sintering
Solution Approach 1:
The invention optimizes the pore diameter parameter to a specific range (0.2 to 0.9 μm) that allows gas escape during degreasing while preventing sintering aid escape during firing. This precise parameter control resolves the contradiction between gas permeability and substance retention.
3Object-generated harmful factors
If porosity is high to enable gas escape, then gas escape is facilitated, but sintering uniformity deteriorates
Solution Approach 1:
The invention optimizes porosity to a specific range (8 vol% or higher) that balances gas escape capability with sintering uniformity. This controlled porosity level resolves the contradiction between gas permeability and sintering quality.
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 proposed setter design ensures effective gas escape during degreasing, suppresses the loss of sintering aids, and promotes uniform sintering, resulting in high-quality ceramic plates with improved strength and reduced color unevenness.
Implementation Method 1
enables at least part of gases that are generated at the time of degreasing green sheets to escape to the outside through pores in the porous body
Implementation Method 2
escape to the outside through pores in the porous body
Implementation Method 3
decrease the pore diameters by contraction at high temperatures, which is a feature of boron nitride sintered plates
Data Source
Figure 1
AI summary
An aspect of the present disclosure provides a setter for ceramic firing, in which the setter is composed of a boron nitride sintered plate having a plurality of pores, a porosity is 8 vol% or higher, and a proportion of pores having a pore diameter of 0.2 to 0.9 µm is 76% to 95% of all pores, the pore diameter being measured with a mercury porosimeter.