Ceramic Sensor Element Welded Contact for High Temperature Stability
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Solution Overview
Problem
Existing temperature sensor elements, particularly NTC sensors, face challenges in long-term durability when exposed to aggressive media and varying usage temperatures, with soldered connections being unreliable due to limited melting temperatures and potential for migration.
Innovation Solution
The use of a ceramic sensor element with layered electrodes, such as perovskite or spinel structures, and contact pieces fastened via welding or bonding, particularly using thin-wire or thick-wire bonding, which improves temperature resistance and stability, and optionally incorporating nickel-containing layers for enhanced mechanical and electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If soldered connections are used for electrical contacting of the ceramic, then the manufacturing process is simple and cost-effective, but the temperature resistance and long-term stability are limited due to melting temperature constraints and migration risks
Solution Approach 1:
The patent changes the connection method from soldering (melting-based) to welding or bonding (diffusion/adhesion-based), fundamentally altering the physical parameter of how electrical contact is established. This enables operation above 300°C without melting, as the connection relies on metallurgical bonding rather than eutectic melting.
Solution Approach 2:
The patent replaces the mechanical/soldering-based connection system with a welding or bonding system. Instead of using solder that melts and solidifies to create joints, the invention uses direct metallurgical bonding processes (welding) or adhesion processes (bonding) to create permanent, heat-resistant electrical connections.
2Reliability
If soldered connections are used for electrical contacting, then the production cost is low, but the long-term stability and migration resistance deteriorate in aggressive media and high temperature environments
Solution Approach 1:
The patent employs composite material structures in the connection system, using specific metal combinations (e.g., silver, gold, copper contact pieces with appropriate ceramic and electrode materials) that provide both electrical conductivity and chemical stability. The multi-layer electrode structures (e.g., nickel-chromium combinations) also represent composite material usage to achieve both adhesion and conductivity.
Solution Approach 2:
The patent introduces intermediate layers and transition structures between the ceramic electrode and the contact piece. These intermediaries (such as specific metallization layers or bonding interfaces) facilitate reliable electrical and mechanical connection while protecting against direct chemical interaction between dissimilar materials, thereby improving long-term stability.
3Temperature
If high lead content solders are used to increase melting temperature, then the temperature resistance improves to approximately 300°C, but lead-free requirements and migration resistance are compromised
Solution Approach 1:
The patent extracts and eliminates lead from the connection system entirely. Instead of using lead-based solders, the invention employs welding or bonding processes that create lead-free, migration-resistant connections. This extraction of the harmful element (lead) while maintaining or improving temperature resistance through alternative bonding mechanisms.
Solution Approach 2:
The patent converts the potential harm of high-temperature exposure to soldered joints into a benefit by using welding or bonding processes that are specifically designed to withstand and even benefit from high-temperature environments. The metallurgical bonds formed through welding actually strengthen at elevated temperatures, turning the previously harmful thermal environment into a condition that validates the connection method.
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 approach enhances the long-term stability and reliability of temperature sensor elements by improving temperature resistance and reducing migration risks, allowing for reliable operation across a broader temperature range without the limitations of soldered connections.
Implementation Method 1
contact piece which is fastened to the electrode by welding or bonding
Implementation Method 2
contact piece which is fastened to the electrode by welding or bonding
Implementation Method 3
the sensor element is an NTC (negative temperature coefficient) sensor element, that is to say a thermistor
Data Source
AI summary
A sensor element, a sensor arrangement, and a method for manufacturing a sensor element and a sensor arrangement are disclosed. In an embodiment, a sensor element includes a ceramic main body having at least one electrode arranged at the main body and having at least one contact piece for the electrical contacting of the electrode, wherein the contact piece is fastened to the electrode by welding or bonding.