Ceramic Member Metal Layer Sintering via Concentration Gradient
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Solution Overview
Problem
Existing methods for manufacturing ceramic members with high void ratio metal layers often result in insufficient sintering of electrodes, leading to decreased electrical conductivity and increased resistance, which affects the sensitivity and efficiency of devices like gas sensors and fuel cells, requiring higher drive voltages and increased electricity consumption.
Innovation Solution
A method involving the formation of ceramic members with a three-layer structure, where a second metallic paste layer with a higher mass percentage of metal component M1 is stacked with a first metallic paste layer, creating a concentration gradient that allows metal component M1 to diffuse through the ceramic layer, increasing the void ratio of the second metal layer and enhancing electrical conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a metal layer is formed with high void ratio to increase gas permeability, then gas permeability is improved, but electrical conductivity decreases due to insufficient sintering
Solution Approach 1:
The patent applies local quality by creating different metal component concentrations in different regions of the same metal layer. The metal component M1 concentration is varied locally to achieve optimal balance between void ratio and electrical conductivity in different areas, allowing gas permeability in high-void regions while maintaining electrical conductivity in regions with sufficient metal content.
Solution Approach 2:
The patent changes the parameter of metal component concentration to resolve the contradiction. By adjusting the mass percentage of metal component M1 in the metallic paste, the invention achieves different sintering outcomes - higher concentration maintains electrical conductivity while lower concentration increases void ratio for gas permeability.
2Object-generated harmful factors
If metal component M1 diffuses through ceramic layer from high concentration to low concentration region, then void ratio of metal layer increases, but manufacturing complexity increases due to concentration gradient requirement
Solution Approach 1:
The patent uses local quality by applying metallic paste with different metal component concentrations at different locations on the ceramic green sheet. This creates the necessary concentration gradient for diffusion while maintaining a relatively simple overall manufacturing process using conventional printing techniques.
Solution Approach 2:
The patent applies preliminary action by pre-establishing the concentration gradient in the metallic paste before sintering. The different metal component concentrations are prepared in advance in different regions, enabling spontaneous diffusion during sintering without requiring complex external control mechanisms.
3Reliability
If electrode is fired at high temperature to achieve sufficient sintering, then electrical conductivity is improved, but ceramic structure may be damaged or gas permeability reduced
Solution Approach 1:
The patent changes the metal component concentration parameter to enable sintering at lower temperatures. By optimizing the metal component M1 mass percentage, the invention achieves sufficient electrical conductivity at temperatures that preserve ceramic structure integrity and maintain gas permeability, avoiding the need for excessively high firing temperatures.
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 manufacture of ceramic members with high void ratio metal layers that maintain sufficient sintering and electrical conductivity, reducing the need for higher drive voltages and improving the sensitivity and durability of devices such as gas sensors and fuel cells.
Implementation Method 1
As the stacked compact is fired with the mass percentage X of the metal component M1 differentiated (rendered a concentration gradient) between the metallic paste layers that adjoin via the ceramic green sheet, it is made possible to cause the metal component M1 to diffuse through the ceramic layer from a layer having a higher mass percentage X to a layer having lower mass percentage X.
Data Source
Figure 1~2(c)
Figure 3~4
Figure 5(a)~5(c)
AI summary
A ceramic member in which the metal layers with high void ratio are sufficiently sintered to lower a residue of resin is produced. The method for manufacturing a ceramic member which comprises a step of forming a stacked compact from a plurality of metallic paste layers containing a metal component M1 that are stacked one on another via ceramic green sheets, and a step of firing the stacked compact, wherein at least one of plural metallic paste layers is formed as a second metallic paste layer that has the mass percentage X higher than that of the metallic paste layer that adjoin therewith in the stacking direction, the mass percentage X being the proportion of the metal component M1 to the total metal content in the metallic paste layer.