Ceramic to Metal Joining via Metallic Barrier Layer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for ceramic-to-metal joining in high-temperature electrochemical cells face challenges due to thermal stress from mismatched coefficients of thermal expansion and the formation of porous metal layers, which can lead to contamination and reduced bond strength, particularly in corrosive environments.
Innovation Solution
A scalable and cost-effective method involving the deposition of a metallic barrier layer with a melting point depressant on a metallized ceramic component, followed by bonding with a metal component using a braze alloy, which reduces porosity and minimizes intermetallic formation through optimized sintering conditions, ensuring a high-strength hermetic seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a porous metal layer is used for plating the metallization surface, then the plating process is simple and cost-effective, but the porous structure leads to contamination and reduced bond strength
Solution Approach 1:
The plating process is divided into two distinct stages: first forming a porous initial plating layer for cost-effective manufacturing, then applying a dense secondary plating layer to eliminate porosity and ensure contamination-free bonding. This segmentation allows each layer to serve its specific function while resolving the contradiction between manufacturing simplicity and bond reliability.
Solution Approach 2:
The plating structure uses a composite approach with two different metal layers: an initial plating layer (e.g., nickel) providing manufacturing efficiency, and a secondary plating layer (e.g., copper or silver) providing contamination resistance and enhanced bonding. This composite structure combines the advantages of both materials to resolve the contradiction.
2Manufacturing precision
If the plating layer is sintered at high temperatures above 1000°C for densification, then porosity is reduced, but intermetallic compounds form at the interface with the metallization layer
Solution Approach 1:
The sintering temperature parameter is changed from conventional high temperatures (>1000°C) to a lower range (800-1000°C). This parameter change achieves sufficient densification of the plating layer while staying below the threshold temperature for intermetallic compound formation, thereby resolving the contradiction between density and harmful factor generation.
Solution Approach 2:
The process applies preliminary anti-action by controlling the sintering temperature to prevent intermetallic formation before it can occur. By maintaining temperature below 1000°C during sintering, the harmful intermetallic reaction is prevented in advance, while still achieving the desired densification effect.
3Reliability
If conventional plating methods (electroplating, electroless plating) are used to achieve a dense metal layer, then contamination is prevented, but the process complexity and cost increase
Solution Approach 1:
The plating process is segmented into two simple sequential steps: screen printing the metal paste followed by low-temperature sintering. This segmentation avoids the need for complex electroplating or electroless plating equipment while achieving contamination-free dense layers through the controlled sintering process at 800-1000°C.
Solution Approach 2:
The complex electrochemical plating systems (electroplating, electroless plating) are replaced with a simpler thermal processing approach. Instead of using electrical fields or chemical baths, the invention uses controlled sintering heat treatment to achieve densification and contamination prevention, thereby reducing device complexity.
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 provides a high-strength, hermetic sealing structure that withstands high temperatures and corrosive environments, maintaining bond integrity and reducing the formation of intermetallic compounds, thus enhancing the reliability and safety of ceramic-to-metal joints.
Implementation Method 1
The P functions as a melting point depressant and is present in 3 to 10 wt%. The goal is to construct a high temperature electrochemical cell.
Implementation Method 2
followed by bonding with a metal component using a braze alloy, which reduces porosity and minimizes intermetallic formation through optimized sintering conditions
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A method for joining a metal component (210) to a ceramic component (204) is presented. The method includes disposing a metallic barrier layer (208) on a metallized portion of the ceramic component (204), and joining the metal component (210) to the metallized portion of the ceramic component (204) through the metallic barrier layer (208). The metallic barrier layer (208) comprises nickel and a melting point depressant. The metallic barrier layer (208) is disposed by a screen printing process, followed by sintering the layer at a temperature less than about 1000 degrees Celsius. A sealing structure including a joint between a ceramic component (204) and a metal component (210) is also presented.