Zinc oxide pressure-sensitive resistor and preparation method thereof

Abstract

The invention discloses a zinc oxide pressure-sensitive resistor. The zinc oxide pressure-sensitive resistor comprises a zinc oxide pressure-sensitive ceramic substrate, electrode layers and electrode leads, wherein the electrode layers are arranged on the upper surface and the lower surface of the zinc oxide pressure-sensitive ceramic substrate respectively; the electrode leads are arranged on the electrode layers respectively. The zinc oxide pressure-sensitive resistor is characterized in that each electrode layer comprises a bottom transition layer which is used for improving bonding force between the zinc oxide pressure-sensitive ceramic substrate and the corresponding electrode layer and reducing contact resistance. Therefore, the electrode layers and the zinc oxide pressure-sensitive ceramic substrate are firmly bonded, and the self through-current capability of the electrode layers is improved. Furthermore, the curved electrode leads are capable of uniformly distributing current on the electrode layers. The surge impact resistance capacity of the zinc oxide pressure-sensitive resistor is improved. The whole preparation process has an environment protection effect, and can reduce over 45 percent of consumed energy and save over 60 percent of production costs compared with the prior art.

Description

technical field [0001] The invention relates to a zinc oxide varistor and a preparation method thereof. Background technique [0002] Zinc oxide varistors are based on zinc oxide powder, doped with metal oxides in different proportions and sintered into a ceramic substrate at high temperature, covered with an electrode layer on the surface of the ceramic substrate, and then welded electrode leads. Zinc oxide Varistors are widely used in various electronic instruments and power facilities because of their good voltage nonlinearity, low limit voltage, large surge resistance, and fast response. [0003] Zinc oxide varistors consist of three parts: a zinc oxide varistor ceramic substrate, an electrode layer arranged on the surface of the zinc oxide varistor ceramic substrate, and an electrode lead welded on the surface of the electrode layer. The electrode layer is used to communicate with the zinc oxide varistor The ceramic substrate produces ohmic contacts, and the electrode ...

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Problems solved by technology

[0006] 1. Since silver and zinc oxide ceramics are mismatched in terms of mechanical properties and electrical properties, it will cause two problems: first, the bonding force between the electrode layer and the zinc oxide varistor ceramic substrate is very poor, generally low For 15N, the electrode layer is easy to fall off during use, the reliability of the device is poor, and the service life is short; second, the ohmic contact resistance is large, generally greater than several ohms, and the heat generated when the surge current passes through such a large ohmic contact resistance It is also correspondingly large, and it is easy to burn the electrode layer

[0007] 2. Since the electrode lead wire is a straight wire, the current is mainly concentrated at the contact between the straight wire and the electrode layer, the current density distribution is extremely uneven, and the strong surge current can easily burn through the electrode layer locally, resulting in resistors permanent damage

[0008] 3. In order to prevent the electrode layer from being burned, the thickness of the silver electrode layer has to reach tens of microns or even hundreds of microns, which requires a large amount of expensive silver materials and high production costs

[0009] 4. The silk screen silver paste on the electrode layer needs to be sintered at a high temperature in a tunnel kiln, which consumes a lot of energy and will volatilize toxic substances such as lead oxide during the process, causing serious pollution and the product does not meet the RoHS standard

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