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High-energy-tolerance ZnO piezoresistor sheet and preparation method therefor

A varistor, high-energy technology, applied in the direction of varistor, varistor core, coating resistance material, etc., can solve the problems of severe heating, falling off, cracking of the encapsulation layer, etc.

Pending Publication Date: 2017-09-08
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, because the ZnO varistor absorbs electric energy and converts it into heat energy after multiple pulse impacts, the internal temperature of the ZnO varistor rises sharply, and the expansion of the organic encapsulation material causes a gap to form between the encapsulation layer and the ZnO varistor sheet. When the pulse impact test is applied to the ZnO varistor, arcing or flashover will occur in the gap, which will cause the encapsulation layer to crack and fall off, and even lead to the overall fragmentation of the ZnO varistor

Method used

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  • High-energy-tolerance ZnO piezoresistor sheet and preparation method therefor
  • High-energy-tolerance ZnO piezoresistor sheet and preparation method therefor
  • High-energy-tolerance ZnO piezoresistor sheet and preparation method therefor

Examples

Experimental program
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Effect test

Embodiment 1~4

[0028] In this embodiment, the shape of the ZnO pressure-sensitive silver sheet is disc-shaped, and the insulating covering material is inorganic glass. The preparation method specifically includes the following steps:

[0029] S11. Making a disc-shaped ZnO varistor ceramic sheet 1 with a diameter of 10 mm and a thickness of 2 mm using the prior art.

[0030] S12, making the silver electrode 2, printing the silver electrode paste on both sides of the ZnO varistor ceramic sheet produced above by using the screen printing process, and the printing pattern on both sides is a circle with a diameter of 7.5 mm. After printing one side, it is baked, and the second side is printed and then baked. The baking temperature is 150°C.

[0031] Put the above-mentioned ZnO varistor ceramic sheet printed with silver electrode paste into a mesh-belt resistance furnace to sinter the silver electrode, and the temperature in the highest temperature zone of the mesh-belt resistance furnace is T1 (s...

Embodiment 5

[0040] In this embodiment, the manufacturing method is the same as that of Embodiment 1 except that organic polymer materials are used to make the ring-shaped insulating covering material 3 .

[0041] In this embodiment, thermosetting resin is selected to make the annular insulating covering material 3. Specifically, a two-component thermosetting resin is used, and the screen printing method is adopted. The printing pattern is a circular ring, the inner diameter of the ring is 6.0 mm, and the outer diameter of the ring is 9.0 mm. After printing one side, it is baked, and the second side is printed and then baked at a temperature of 150° C., and then placed in a baking oven at 150° C. for 30 minutes to complete the preparation of the annular insulating covering material 3 .

[0042] The test method is the same as that of Example 1. After welding the lead wires, the sample of this example has a good appearance after being subjected to 25 pulses of 4kV / 2kA, and no edge or side arc...

Embodiment 6

[0044] In this embodiment, the manufacturing method is the same as that of Embodiment 1 except that organic polymer materials are used to make the ring-shaped insulating covering material 3 .

[0045] In this embodiment, photocurable resin is used to make the ring-shaped insulating covering material 3. Specifically, UV-curable epoxy acrylic resin is used, and the screen printing method is adopted. The printing pattern is circular, the inner diameter of the ring is 6.0 mm, and the outer diameter of the ring is 9.0 mm. One side was printed and cured by ultraviolet light for 5 minutes, and then the second side was printed and cured by ultraviolet light for 5 minutes, thereby obtaining a ZnO varistor sheet covered with the annular insulating material 3 .

[0046] The test method is the same as that of Example 1. After welding the lead wires, the sample of this example has a good appearance after being subjected to 25 pulses of 4kV / 2kA, and no edge or side arc flashover occurs.

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Abstract

The invention provides a high-energy-tolerance ZnO piezoresistor sheet and a preparation method therefor. A ZnO voltage-sensitive ceramic sheet is manufactured firstly; then silver electrode slurry is printed on the two surfaces of the ZnO voltage-sensitive ceramic sheet, and is sintered to form a silver electrode to obtain a ZnO voltage-sensitive silver sheet with silver electrodes on the two surfaces; finally, an annular insulating and covering material is prepared on the edges of the silver electrodes on the two surfaces of the ZnO voltage-sensitive silver sheet to prepare the ZnO piezoresistor sheet covered with the annular insulating material; and the annular insulating material covers the edges of the silver electrodes for a range of 0.5mm or above inside and outside. No matter whether the prepared ZnO piezoresistor sheet is packaged by adopting an organic material or not or whether the prepared ZnO piezoresistor sheet suffers from a pulse current or not, flashover or arc-over does not occur on the edge and side surface, so that high reliability is achieved.

Description

technical field [0001] The invention relates to a ZnO varistor and a manufacturing method thereof, in particular to a ZnO varistor sheet free of encapsulation and capable of withstanding high pulse energy density and a manufacturing method thereof. Background technique [0002] ZnO varistors have been widely used in power electronic circuits to absorb or suppress abnormal overvoltage to protect power electronic equipment from damage. [0003] Usually the method of making ZnO varistor is: manufacture ZnO varistor, prepare metal electrodes on both sides of ZnO varistor, obtain ZnO varistor with voltage non-linear characteristics; The lead wires are welded on the two metal electrodes, and the ZnO varistor sheet body is encapsulated with epoxy resin to make a ZnO varistor. [0004] ZnO varistors need to withstand pulse voltage or pulse current. If ZnO varistors are not encapsulated with organic materials when using existing ZnO varistors, ZnO varistors will withstand pulse volt...

Claims

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Application Information

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IPC IPC(8): H01C7/112H01C17/06
CPCH01C7/112H01C17/06
Inventor 卢振亚刘兴悦
Owner SOUTH CHINA UNIV OF TECH
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