Coating device and coating method for internal catalyst layer of oxygen sensor

Abstract

The invention discloses a coating device and a coating method for an internal catalyst layer of an oxygen sensor. The coating device comprises an external sealing layer which is in close fit with the inner wall of a zirconium tube of an oxygen sensor; the coating device also comprises a compressed air channel layer which is concentric with the external sealing layer, an annular hollow space between the external sealing layer and the compressed air channel layer is a backflow channel, and a circular hollow area surrounded by the compressed air channel layer is a channel filling compressed air into the backflow channel; and the front end of the compressed air channel layer is of an open structure. According to the device and the method, platinum paste can be uniformly coated at a position on the zirconium tube of the oxygen sensor and corresponding to an external catalyst layer in a compressed air blowing mode so as to form the internal catalyst layer corresponding to the external catalyst layer; and according to the coating device and coating method disclosed by the invention, the internal catalyst layer can enable an oxygen sensor to have a good electrical property, and in the process of coating, the application amount of platinum paste is reduced, and the cost of the oxygen sensor is lowered.

Description

technical field [0001] The invention relates to a metal layer coating device and method, in particular to a coating device and method for a catalytic layer inside a zirconium tube of an oxygen sensor. Background technique [0002] For the oxygen sensor used in automobiles, the diameter of the inner hole of the zirconium tube is relatively small, generally within 5 mm. The inner hole of the oxygen sensor zirconium tube has an inner catalytic layer 120, and the outer wall of the oxygen sensor zirconium tube has an outer catalytic layer 110, such as figure 1 As shown, the inner catalytic layer 120 and the outer catalytic layer 110 are mainly used for adsorption and desorption reactions of oxygen ions, and are used for generating oxygen ion signals. [0003] Due to the small diameter of the inner hole of the oxygen sensor zirconium tube, it is difficult to coat the inner catalytic layer 120 on the inner hole. At present, the following two methods are mainly used to coat the inn...

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Problems solved by technology

[0005] When the brushing method is used, the distance between the platinum slurry and the heating area of ​​the heater and the external catalytic layer is relatively long, the oxygen ion transmission path is too long, the sensor response is slow, and the performance is poor

[0006] The second is the overall grouting method, such as figure 2 As shown, this method is mainly to fill the interior of the zirconium tube with the platinum slurry as a whole, and then tilt the zirconium tube to allow the platinum slurry to flow out to form the internal catalytic layer 120. This method can achieve better electrical performance of the sensor, but it is for Platinum is overused and expensive

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