Ceramic Pressure Sensor Diffusion Weld for Corrosion-Tight Sealing
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Solution Overview
Problem
Classic ceramic pressure sensors face challenges with corrosion resistance and sealing integrity, especially when measuring highly corrosive media, due to the use of elastomers and thermoplastics, and the high production costs and stress risks associated with sapphire-based solutions.
Innovation Solution
A ceramic pressure sensor with a titanium or titanium alloy fastening element, where the membrane edge is directly connected to the fastening element via diffusion welding, creating a diffusion-tight and highly corrosion-resistant seal without the need for joining materials, and featuring a design that can withstand thermomechanical stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If elastomers or thermoplastics are used as sealing materials in classic ceramic pressure sensors, then the device can be manufactured with conventional sealing methods, but the sealing integrity deteriorates over time due to aging and lack of diffusion-tightness
Solution Approach 1:
The invention extracts and eliminates the sealing materials (elastomers, thermoplastics) from the pressure sensor structure. By removing these non-diffusion-tight materials, the patent achieves a diffusion-tight seal through the direct contact between the ceramic membrane edge and the process connection, prevented by the crystalline structure of the ceramic material itself.
Solution Approach 2:
The invention applies local quality by utilizing the inherent crystalline structure of the ceramic material at the specific location where sealing is required (the membrane edge interface). The ceramic's crystalline structure provides natural diffusion-tightness at the sealing interface without requiring additional sealing materials throughout the entire device.
2Object-affected harmful factors
If sapphire-based solutions are used to achieve corrosion resistance, then the pressure sensor can withstand corrosive media, but the production costs increase significantly
Solution Approach 1:
The invention applies homogeneity by using the same ceramic material (polycrystalline ceramic with crystalline structure) for both the membrane and the sealing interface. This eliminates the need for expensive sapphire or other premium materials, as the homogeneous ceramic material provides both structural function and corrosion resistance throughout the device.
Solution Approach 2:
The invention replaces expensive sapphire-based solutions with more economical polycrystalline ceramic materials. While sapphire provides excellent corrosion resistance, the patent demonstrates that standard polycrystalline ceramics with appropriate crystalline structures can achieve sufficient corrosion resistance at much lower production costs.
3Ease of manufacture
If joining materials are used to connect the membrane edge to the fastening element, then the connection can be easily manufactured, but the diffusion-tightness and corrosion resistance are compromised
Solution Approach 1:
The invention extracts and removes all joining materials (solders, adhesives, brazing materials) from the connection between the membrane edge and the fastening element. By eliminating these materials, the patent achieves a direct, diffusion-tight connection that is inherently corrosion-resistant, as no foreign materials are present to compromise the seal or corrode.
Solution Approach 2:
The invention merges the membrane edge directly with the fastening element through a diffusion bond, creating a unified structure without intermediate joining materials. This direct merging ensures that the interface between ceramic and metal is diffusion-tight and corrosion-resistant, as there are no separate materials to fail or corrode.
4Object-affected harmful factors
If the membrane edge is directly connected to the fastening element via diffusion welding, then corrosion resistance and diffusion-tightness are improved, but the manufacturing process becomes more complex
Solution Approach 1:
The invention applies parameter changes by utilizing specific temperature and pressure parameters during the diffusion bonding process. By controlling these parameters, the patent achieves a direct metal-ceramic bond between the membrane edge and fastening element that is both diffusion-tight and highly corrosion-resistant, eliminating the need for intermediate materials.
Solution Approach 2:
The invention creates a composite material interface through diffusion bonding, where the ceramic membrane edge and metal fastening element form a metallurgically bonded composite structure. This composite interface provides both the mechanical strength of metal and the corrosion resistance of ceramic, with a diffusion-tight boundary between the two materials.
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 provides a robust, corrosion-resistant, and diffusion-tight sealing mechanism that maintains measurement accuracy even with rough ceramic surfaces, allowing for the use in corrosive environments without increasing production costs or compromising sensor integrity.
Implementation Method 1
the membrane edge of the measuring membrane is directly connected to the fastening element by means of a diffusion weld
Data Source
Figure 1~2
Figure 3a~3c
AI summary
The invention relates to a pressure measuring device comprising a ceramic pressure sensor (1), which comprises a ceramic measuring membrane (3), and a sensor securing device, by means of which the pressure sensor (1) is secured such that a medium under a pressure (p) to be measured can be applied to a measuring membrane (3) region surrounded externally on all sides by a membrane edge (5) of the measuring membrane (3). The sensor securing device comprises a securing element (9) made of titanium or a titanium alloy, having an opening (11) through which the medium under the pressure (p) to be measured can be applied to the membrane region. According to the invention, the corrosion resistance of the pressure measuring device is improved in that the membrane edge (5) of the measuring membrane (3) is directly connected to the securing element (9) of the sensor securing device by means of a diffusion welding (7), wherein the diffusion welding (7) is a diffusion welding (7) which is produced using a diffusion welding method and by means of which the measuring membrane (3) provided as an individual part during the diffusion welding method is connected to the securing element (9).