Aluminum-silver combined electrode pressure-sensitive resistor and preparation method thereof

Abstract

The invention provides an aluminum-silver combined electrode pressure-sensitive resistor and a preparation method thereof. The aluminum-silver combined electrode pressure-sensitive resistor comprises a pressure-sensitive resistor ceramic body and an aluminum metal layer and a silver metal layer which are arranged on two surfaces of the pressure-sensitive resistor ceramic body, wherein the silver metal layer is arranged on the surface of the aluminum metal layer; the silver metal layer comprises a welding region covering the surface of the aluminum metal layer and a pressure drop buffer region; the welding region is a compact layer arranged in a region needing welded metal leads or metal spring plates, or the welding region is a compact layer arranged in the middle part or the side of the aluminum metal layer; and the pressure drop buffer region is a filament gridding or dot matrix structure covering other regions except the aluminum metal layer of the welding region. The preparation method comprises the following steps: firstly printing aluminum paste in a silk-screen manner on the surface of a pressure-sensitive resistor ceramic sheet, then printing silver paste on the surface of the pressure-sensitive resistor ceramic sheet, adopting a twice sintering technology or a once sintering technology to sinter a combined electrode. The using amount of silver is greatly reduced, and simultaneously, the technological requirement of large through-flow is met.

Description

technical field [0001] The invention relates to the technical field of zinc oxide varistor production, in particular to an aluminum-silver composite electrode varistor and a preparation method thereof. Background technique [0002] Zinc oxide varistor is a voltage limiting protection device. Utilizing the nonlinear characteristics of the varistor, when an overvoltage occurs between the two poles of the varistor, the varistor can clamp the voltage to a relatively fixed voltage value, thereby realizing the protection of the subsequent circuit. Due to the above-mentioned characteristics of the varistor, it is widely used in the fields of electronic equipment, household appliances, power electronics and the like. In order to realize the function of the varistor, a weldable electrode layer must be made on both sides of the varistor ceramic, so as to weld the lead wire or metal sheet, and finally connect the varistor to the electronic circuit through the lead wire or metal shee...

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Problems solved by technology

[0007] 1. The process is complicated, the process control is difficult, and the tooling requirements are high. This process requires a large number of tooling molds to ensure that the sprayed electrode patterns meet the design requirements, and these molds have high requirements for processing accuracy and materials used, and are used Frequent cleaning is required during the process, which virtually increases the manufacturing cost of the electrode layer

[0008] 2. Low efficiency and large material waste. The thermal spraying process is suitable for large-scale continuous area coating, while the electrode layer area of ​​the zinc oxide pressure-sensitive ceramic chip is very small, and it must be installed in the fixture when spraying, which has a great impact In order to improve the working efficiency, at the same time, a considerable part of the metal material is not sprayed on the pressure-sensitive ceramic piece, resulting in waste

[0009] 3. Loud noise, metal dust pollution and potential safety hazards. The high-speed airflow in the thermal spray gun produces a lot of noise. In addition, a large amount of metal dust is generated during the spraying process, which pollutes the environment. When the concentration reaches a certain level, there is a danger of explosion with fire

[0010] The zinc oxide varistor electrode produced by the above-mentioned process method inevitably has the above disadvantages while saving the cost of materials.

The traditional screen printing silver paste to make zinc oxide varistor electrodes has mature technology, high efficiency and low pollution, but the amount of precious metal silver is large and the cost of materials is high.

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