Novel tubular sensing element and preparation method thereof

Abstract

The invention discloses a novel tubular sensing element and a preparation method thereof. The novel tubular sensing element comprises a tubular ceramic substrate, an outer electrode arranged on the outer surface of the ceramic substrate and an inner electrode arranged on the wall of an inner cavity. One purpose of the invention is to provide a novel tubular sensing element with low cost and high performance, and the external catalytic electrode part of the sensing element is composed of a novel ceramic catalytic electrode, so that the sensing element provided by the invention also has the characteristics of low cost and excellent catalytic performance. Another purpose of the invention is to provide a preparation method of the novel tubular sensing element. The sensing element prepared by the method is simple in process operation, good in combinability of an electrode material and a ceramic matrix, low in noble metal consumption and good in catalytic activity. The invention is especially suitable for the technical field of oxygen sensors.

Description

technical field [0001] The invention relates to the field of oxygen sensors, in particular to a novel tubular sensing element and a preparation method thereof. Background technique [0002] In the control system of the vehicle engine, ensuring that the engine works with the mixture of the best air-fuel ratio is a key technology for emission control. The vehicle oxygen sensor is a key component for controlling the air-fuel ratio of the engine mixture. The oxygen sensor is Feedback the gas condition after mixed combustion of oil and gas to a key component of the engine control unit (ECU) in real time. The engine electronically controlled injection system precisely controls the air-fuel ratio (A / F, the mass ratio of air to gasoline) based on the signal provided by the oxygen sensor. . [0003] The three-way catalytic converter is the most important external purification device installed in the automobile exhaust system. It can convert harmful gases such as CO, HC and NOx emitt...

AI Technical Summary

Problems solved by technology

For electroplating electrode technology, refer to the publication specification of invention patent application CN200310114168.7, etc. The advantages of electroplating electrodes are that the prepared electrode layer is very thin, the dosage is small, and there are more three-phase interfaces and good activity, which effectively solves the problem of the amount of noble metal used in co-fired electrodes. There are many problems, but the bonding reliability between the electrode material and the substrate is relatively poor, and it is easy to peel off; and the electroplating process is relatively complicated, and it is easy to pollute the environment

[0007] The co-firing technology of electrodes and solid electrolyte ceramics refers to application number 200410064804.4, etc. The advantage of co-fired electrodes is that the bonding reliability between the electrode layer and the substrate is better, and the problem of easy peeling off of the electrode layer directly coated is improved. A thick film is used, with a thickness of 6-10 microns. The platinum particles are micron-scale or sub-nano-scale noble metal particles, and the electrode material is co-fired at a high temperature of 1400-1550°C. The low-temperature catalytic activity of the electrode is relatively poor. At the same time, the three-phase The interface also has a certain loss, so under the condition of obtaining the same catalytic activity, more precious metals are needed, and the cost is high

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