Gas Sensor Protection Layer Anchoring via Electrode Openings
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Solution Overview
Problem
Conventional gas sensors experience changes in sensor output and protection layer detachment due to thermal aggregation of sintered particles on the measuring electrode when exposed to high temperatures, which affects gas diffusion and electrode activity.
Innovation Solution
A gas sensor design featuring a measuring electrode with multiple opening portions that allow the porous ceramic protection layer to be joined to the solid electrolyte body, reducing thermal aggregation and enhancing the protection layer's anchoring, thereby minimizing changes in sensor output and protection layer detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the protection layer is merely in contact with the surface of the measuring electrode, then the structure is simple, but the protection layer is easily detached and thermal aggregation occurs
Solution Approach 1:
The protection layer is positioned to extend through the opening portions of the measuring electrode, creating a nested configuration where the protection layer is anchored within the electrode structure. This nesting arrangement provides secure attachment while maintaining structural simplicity
Solution Approach 2:
The protection layer is designed to extend in the thickness direction of the measuring electrode, transitioning from simple surface contact to a three-dimensional anchored configuration. This dimensional change enables the protection layer to be fixed at multiple positions (surface and through-opening), significantly improving attachment stability
2Duration of action of stationary object
If the measuring electrode is exposed to high temperature measured gas for long periods, then the sensor can operate continuously, but thermal aggregation occurs causing changes in sensor output
Solution Approach 1:
The measuring electrode is designed with opening portions at specific locations where the protection layer can extend through. This local structural modification creates anchor points that prevent thermal aggregation at critical positions, maintaining sensor output stability during continuous high-temperature operation
Solution Approach 2:
The protection layer is pre-positioned to extend through the opening portions of the measuring electrode before operation begins. This preliminary anchoring configuration prevents thermal aggregation and maintains electrode structure integrity during subsequent high-temperature exposure, ensuring stable sensor output
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 design effectively reduces thermal aggregation on the measuring electrode, stabilizes gas diffusion and electrode activity, and enhances the protection layer's joining performance, leading to more stable sensor output and reduced protection layer detachment.
Implementation Method 1
a porous protection layer which protects the measuring electrode from toxic substances in the measured gas and moisture
Implementation Method 2
a porous protection layer which protects the measuring electrode from toxic substances in the measured gas and moisture
Implementation Method 3
a solid electrolyte body which is formed, from an oxygen-ion conductive ceramic
Implementation Method 4
the gas sensor detects an oxygen-ion current which is generated between the measured gas electrode and the reference gas electrode, according to a difference in the oxygen concentration
Implementation Method 5
the measuring electrode is an electrode onto which an oxygen decomposing reactions occur, for example, by contact of a measured gas with the measuring electrode
Implementation Method 6
a sensor element is thus subjected to exposure to high temperature measured gas for long periods, which can cause progressed sintered particles of solid electrolytes and noble metals which configure a measuring electrode and a reference electrode. Such progression of crystallization is called thermal aggregation which is based on a contraction phenomenon of each particle due to heat
Implementation Method 7
thermal aggregation which is based on a contraction phenomenon of each particle due to heat
Data Source
AI summary
A sensor element of a gas sensor includes a solid electrolyte body which has oxygen-ion conductivity, a measuring electrode that is exposed to a measured gas, a reference gas electrode that is exposed to a reference gas, and a porous protection layer. The measuring electrode is mounted on an outer surface of the solid electrolyte body. The reference electrode is mounted on an inner surface of the solid electrolyte body. The protection layer covers a surface of the measuring electrode. A plurality of open portions are formed to penetrate through the measuring electrode. A part of the protection layer is joined to the solid electrolyte body, via the plurality of open portions.