Nitrogen-oxygen sensor ceramic chip diaphragm

Abstract

The invention discloses a nitrogen-oxygen sensor ceramic chip diaphragm, which comprises a first diaphragm layer, a fifth diaphragm layer, a sixth diaphragm layer and an external electrode, the external electrode is installed at the top of the first diaphragm layer through silk-screen printing, the fifth diaphragm layer is installed below the first diaphragm layer, the sixth diaphragm layer is installed at the bottom of the fifth diaphragm layer, a stable second membrane layer is installed at the bottom of the first membrane layer, a third membrane layer is installed at the bottom of the second membrane layer, water vapor in tail gas can be effectively prevented from entering the membrane through the arrangement of a PVA coating high-barrier thin film, and cracking caused by thermal expansion and cold contraction of a ceramic chip when the ceramic chip encounters water is avoided; and meanwhile, each diaphragm layer of the diaphragm is of a porous structure, interfaces between functional layers are combined into a whole, the structural strength and stability of the nitrogen-oxygen sensor chip are improved to a great extent, and the stability and the anti-creeping function of the whole ceramic chip are greatly improved by reducing the number of the cavities and increasing the number of the insulating layers.

Description

technical field [0001] The invention relates to the technical field of nitrogen and oxygen sensors, in particular to a diaphragm of a nitrogen and oxygen sensor ceramic chip. Background technique [0002] The nitrogen oxygen sensor is a gas sensor used to detect nitrogen oxides in diesel vehicle exhaust. As the country pays more and more attention to environmental protection, the control of NOx emission limits in the emission regulations is becoming more and more strict. In order to reduce NOx emissions of diesel vehicles, the engine exhaust system has added a selective catalytic reduction system (SCR). The principle is that when the engine exhaust gas is discharged, urea is sprayed and mixed with it, and NH is used on the catalyst surface of the SCR system to 3 Reduce NO x , reacting to the harmless N 2 . It is in this system that the nitrogen and oxygen sensor plays a role in monitoring NO x content, to control the role of urea injection volume. [0003] The current...

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Problems solved by technology

[0003] The current nitrogen and oxygen sensor ceramic chip has multiple gas cavities inside, the manufacturing process is relatively complicated, and it is an internal multi-cavity structure, which leads to the decline of its own thermal shock resistance, and crack damage is prone to occur on the edge of the cavity, reducing its use Life, but the existing diaphragm has poor heater insulation performance and leakage problems, so the diaphragm is needed to protect it Nitrogen sensor ceramic chip

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