A making method of silver/graphite electrical contact

An electrical contact and graphite technology, which is applied to contacts, circuits, electrical switches, etc., can solve the problems of increased production cost, low product yield, and expensive raw materials, and achieves low production cost, good product performance, and simple process. Effect

Inactive Publication Date: 2007-12-12
HARBIN ENG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

German Degussa company developed an extrusion process for preparing silver / graphite electrical contacts, and produced silver / graphite electrical contact materials with high density, good ductility and significantly improved arc corrosion resistance, but the above two methods or raw material prices are relatively high. Expensive, or product yields are low, leading to higher final production costs

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Mix expanded graphite (expansion volume: 200mL / g, purity 99.5%) and silver powder (average particle size 70nm) in a planetary high-energy ball mill, the number of revolutions is 100rpm, the ball-to-powder ratio is 10:1, the ball milling time is 40 hours, and the ball mill The mixed expanded graphite and silver powder raw materials are initially formed under a pressure of 20t, sintered in a sintering furnace at 600°C under the protection of a hydrogen atmosphere, and finally recompressed under a pressure of 50t to obtain a finished product (the weight content of expanded graphite is 10%). Its physical and mechanical properties are listed in Table 1.

Embodiment 2

[0025] Expanded graphite (expansion volume: 300mL / g, purity 99.9%) and silver powder (average particle size 70nm) were mixed in a planetary high-energy ball mill, the number of revolutions was 250rpm, the ball-to-powder ratio was 30:1, and the ball milling time was 5 hours. The expanded graphite mixed with the ball mill and the silver powder raw materials are initially formed under a pressure of 20t, sintered in a sintering furnace at 600°C under the protection of a hydrogen atmosphere, and finally recompressed under a pressure of 50t to obtain a finished product (the weight content of the expanded graphite is 5% ). Its physical and mechanical properties are listed in Table 1.

Embodiment 3

[0027] Mix expanded graphite (expanded volume: 400 mL / g, purity 99.9%) with silver nitrate solution complexed with ammonia water to a pH of 10 and a concentration of 0.5 mol / L, and stir well. Then, 10% hydrazine hydrate solution was added dropwise while stirring to obtain silver / expanded graphite coated powder. The coated powder obtained was washed with water until neutral, and dried at 100°C. The dried silver / expanded graphite coated powder is preformed under a pressure of 20t, sintered in a sintering furnace at 850°C under the protection of a hydrogen atmosphere, and finally recompressed under a pressure of 60t to obtain a finished product (the weight content of expanded graphite is 3 %). Its physical and mechanical properties are listed in Table 1.

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PUM

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Abstract

The invention provides a method of producing high performance Argentine / graphite electronic contactor material, it includes following steps: 1) expanded graphite and Argentine are combined to produce raw material powder, the weight ratio of expanded graphite is 3-10%, the weight ratio of Argentine is 90%-97%; 2) Argentine / graphite raw material powder obtained in step 1) is sintered, and pressed to molding. The craftwork of the invention is easy, it convenient to operate, requirement of equipment is low, cost of production is low; the performance of product produced is well, nanophase graphite piece is even in material, resistivity is low, density is high, it possesses perfect performance of anti-arc corrosion.

Description

(1) Technical field [0001] The invention relates to a method for preparing a silver / graphite electric contact, belonging to the field of electric contact material manufacturing. (2) Background technology [0002] Silver / graphite (Ag / C) electrical contact material is widely used in various protective devices due to its good welding resistance and electrical conductivity, low and stable contact resistance and excellent low temperature rise characteristics. In this material, the matrix silver provides good electrical conductivity without forming a stable oxide that will not cause a sharp increase in contact resistance during use, and the main role of graphite is to prevent contact bonding and welding , and does not form any insulators to increase the contact resistance. However, graphite has a tendency to stabilize the arc and has poor thermal stability in air, so poor arc corrosion resistance is the biggest defect of the material. [0003] The use of micron-sized synthetic g...

Claims

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Application Information

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IPC IPC(8): H01H1/0233H01H11/04
Inventor 魏彤范壮军解大收张瑞姚静鄢少锋段斐李佳晶
Owner HARBIN ENG UNIV
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