Gradient Cermet Electrical Bushing for Implantable Devices
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Solution Overview
Problem
Existing methods for producing electrical bushings for implantable devices face challenges in achieving a hermetic seal due to weak spots at the interfaces between conducting wires and insulating ceramic base bodies, which are costly to metallize and prone to gaps.
Innovation Solution
A method involving the formation of a green blank from a ceramic slurry with a bushing conductor made of metal or cermet powder, where the metal fraction decreases from the center to the base body, ensuring a sintered, gap-free connection through a gradual metal fraction gradient, balancing shrinkage and preventing hermetic sealing failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metallization is applied to the internal surface of the bore hole to achieve gap-free connection, then hermetic sealing is improved, but manufacturing cost and complexity increase significantly
Solution Approach 1:
The invention uses a composite material consisting of ceramic powder and metal powder mixed in specific proportions. The metal powder content varies between 5-50 weight percent, creating a composite that combines the hermetic sealing properties of ceramic with the gap-free connection properties of metal, eliminating the need for separate metallization steps
Solution Approach 2:
The invention applies local quality by varying the metal powder content in different regions of the bushing material. The metal powder content is specifically controlled to be between 5-50 weight percent in the region surrounding the bore hole, while other regions may have different compositions, optimizing both hermetic sealing and electrical connection properties locally
2Manufacturing precision
If homogeneous metallization is ensured in the bore hole, then gap-free connection is achieved, but manufacturing cost increases
Solution Approach 1:
The invention changes the material composition parameter by incorporating metal powder in varying concentrations (5-50 weight percent) directly into the ceramic matrix during the green blank formation stage. This allows homogeneous distribution of conductive properties throughout the bushing material without requiring post-forming metallization processes
Solution Approach 2:
The invention performs preliminary action by mixing the metal powder and ceramic powder together before forming the green blank. This preliminary mixing ensures homogeneous distribution of the conductive phase throughout the insulating matrix, eliminating the need for subsequent metallization steps and reducing manufacturing costs
3Reliability
If metal fraction decreases towards the base body, then shrinkage is balanced and hermetic sealing is improved, but material composition complexity increases
Solution Approach 1:
The invention applies local quality by creating a spatial gradient in metal powder concentration. The metal fraction is specifically controlled to decrease towards the base body, with higher metal content (up to 50 wt%) near the bore hole for electrical connection and lower metal content (down to 5 wt%) towards the base body for hermetic sealing and shrinkage control
Solution Approach 2:
The invention uses parameter changes by varying the metal powder weight percent as a function of position within the bushing. This gradient in composition (from 5-50 wt% metal powder) allows optimization of different functional requirements in different regions: electrical conductivity near the conductor and hermetic sealing toward the base body
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 achieves a firmly bonded, hermetically sealed electrical bushing with reduced tension and defects, enhancing the long-term reliability of the seal and reducing manufacturing costs by eliminating the need for costly metallization procedures.
Implementation Method 1
It includes sintering the green blank that includes the base body and the bushing conductor
Data Source
AI summary
One aspect relates to a method for producing an electrical bushing for an implantable device, an electrical bushing, and an implantable device. The method according to one embodiment includes forming a base body from a ceramic slurry and introducing a bushing conductor made of a metal or cermet material with a metal fraction into the base body. The metal fraction in the bushing conductor is provided to decrease towards the base body. It includes sintering the green blank that includes the base body and the bushing conductor.