Piezoelectric Monoblock Sintering for Low-Temperature Joining
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Solution Overview
Problem
Existing piezoelectric transmitting and/or receiving devices face challenges in manufacturing due to the need for high surface quality components and high temperatures for diffusion welding, which can damage the piezo elements and are costly and complex, especially since they require expensive surface preparation and high-voltage polarization in a protective atmosphere.
Innovation Solution
A piezoelectric transmitting and/or receiving device is produced using a sintering process that forms a monoblock with the piezo element and electrodes, eliminating the need for centering devices and allowing for lower temperature processing, using a silver-based sintering material with nanoscale silver particles to reduce costs and mechanical stresses, and incorporating insulation elements for a compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If diffusion welding is used to join piezo elements and electrodes, then firm connection is achieved, but very high temperatures are required that can damage piezoelectric properties
Solution Approach 1:
The patent changes the joining temperature parameter from diffusion welding temperatures (near solidus line) to sintering temperatures (below Curie temperature). This parameter change allows achieving firm connections while preserving piezoelectric properties, as the sintering process occurs at temperatures that do not damage the piezoelectric material.
Solution Approach 2:
The patent replaces the diffusion welding process with a sintering process. Instead of using diffusion welding mechanisms (high temperature, high pressure, surface diffusion), the invention uses sintering mechanisms (lower temperature, pressure application, particle bonding) to achieve the same joining function while being compatible with piezoelectric materials.
2Strength
If diffusion welding is used to join components, then firm connection is achieved, but manufacturing complexity and cost increase due to surface quality requirements and protective atmosphere
Solution Approach 1:
The patent uses a sintering paste as a consumable material that facilitates the joining process. The paste is applied to component surfaces, enables bonding during sintering, and then burns away or integrates into the joint. This disposable approach simplifies the process compared to diffusion welding, which requires precise surface preparation and controlled atmospheres.
Solution Approach 2:
The sintering paste acts as an intermediary material between the piezo elements and electrodes. It facilitates the joining process by enabling bonding at lower temperatures and simpler conditions compared to direct diffusion welding. The paste mediates the interaction between components, allowing firm connections without the complexity of diffusion welding requirements.
3Reliability
If high-voltage polarization is performed in protective atmosphere, then piezoelectric properties are established, but manufacturing cost and process complexity increase
Solution Approach 1:
The patent combines the polarization process with the sintering process. Instead of performing polarization separately in a protective atmosphere after assembly, the invention integrates polarization into the sintering step. The piezoelectric properties are established during the sintering process itself, eliminating the need for separate polarization equipment and protective atmosphere requirements.
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 method allows for cost-effective and simplified production at lower temperatures, ensuring optimal alignment and retention of piezoelectric properties, with reduced mechanical influences and enhanced power development by maximizing the area of piezoelectric elements.
Implementation Method 1
at least the piezo element and the electrodes being sintered to form a monoblock
Implementation Method 2
a piezoelectric transmitting and/or receiving device having at least one piezo element
Data Source
Figure 1a~1b
Figure 2
Figure 3
AI summary
Disclosed is a piezoelectric transmission and/or reception device (1) consisting of - at least one piezo element (3), - at least two electrodes (5) for making contact with the piezo elements (3), and - at least two insulating elements (7) for providing top and bottom insulation; at least the piezo element (3) and the electrodes (5) are sintered in such a way as to form a single block.