Ceramic Heater Terminal Joining Layer Design
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Solution Overview
Problem
Existing ceramic structures with metal terminals face issues with joining strength and reliability due to thermal expansion mismatches, leading to potential peeling of the joining layer, which can result in electrical connection failures and positional deviations.
Innovation Solution
A ceramic structure with a metal terminal and a joining layer containing metal, where the joining layer extends from the terminal to a second surface within the ceramic base body, intersecting with the first surface, enhancing the joining strength and reliability by managing thermal expansion differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a joining layer is used to bond the ceramic base body and metal terminal, then the electrical connection is established, but the joining layer peels due to thermal expansion mismatch
Solution Approach 1:
The joining layer is extended from a simple surface-level bond to a three-dimensional structure that penetrates into the ceramic base body along the thickness direction. This dimensional extension creates anchor points within the ceramic, transforming a two-dimensional surface bond into a multi-point three-dimensional connection that resists peeling forces.
Solution Approach 2:
The joining layer is divided into multiple functional regions: a first region at the surface level for electrical connection, and a second region extending into the ceramic base body for mechanical anchoring. This segmentation allows each region to perform its specialized function - the surface region provides electrical conductivity while the embedded region provides structural stability.
2Strength
If the joining layer is extended deeper into the ceramic base body, then the joining strength improves, but the manufacturing complexity increases
Solution Approach 1:
The joining layer formation process is merged with the existing ceramic manufacturing process. The joining layer is formed as an integral part of the ceramic structure during the same manufacturing cycle, eliminating the need for separate embedding steps and reducing overall manufacturing complexity despite the enhanced three-dimensional structure.
Solution Approach 2:
The joining layer is prepared in advance as a precursor structure before the ceramic manufacturing process completes. By pre-forming the joining layer with its extended structure, the subsequent ceramic processing steps automatically complete the embedding without requiring additional complex operations.
3Ease of manufacture
If the joining layer is positioned only at the surface level, then the manufacturing process is simple, but the electrical connection reliability deteriorates under thermal stress
Solution Approach 1:
The joining layer transitions from a two-dimensional surface layer to a three-dimensional structure with depth penetration. This dimensional change maintains manufacturing simplicity by using the same surface deposition techniques while adding the depth dimension that provides thermal stress resistance through mechanical anchoring in the ceramic substrate.
4Stability of the object's composition
If the ceramic base body undergoes thermal expansion, then the structural integrity is maintained, but the joining layer peels due to differential expansion with the metal terminal
Solution Approach 1:
The joining layer is designed with extended depth penetration into the ceramic base body before thermal cycling occurs. This pre-established deep anchoring structure acts as a cushion against thermal expansion stresses, absorbing the differential expansion forces between the metal terminal and ceramic base body and preventing peeling during subsequent thermal cycles.
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 solution significantly reduces the probability of peeling and improves the reliability of the electrical connection between the terminal and the ceramic base body, maintaining structural integrity and functionality under temperature changes.
Implementation Method 1
Existing ceramic structures with metal terminals face issues with joining strength and reliability due to thermal expansion mismatches
Data Source
AI summary
A heater includes a base body, terminal and joining layer. The base body is made of ceramic. The joining layer contains metal as a principal ingredient and is located between the base body and the terminal. The base body includes a first surface and second surface. The first surface faces an outer side of the base body and includes at least one of a region which is superimposed on the terminal and a region which is located on a periphery of the terminal. The second surface intersects with the first surface and is located on the side closer to an internal portion of the base body on the side away from the first surface. The joining layer extends from the terminal and first surface up to the second surface.