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Methods for manufacturing an electrical contact pad and electrical contact

An electrical contact pad and electrical contact technology, applied in the field of electrical contacts, can solve the problems of difficult pad assembly, high manufacturing cost and the like

Active Publication Date: 2012-10-31
METALOR TECH INT
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] These conventional methods include many operations that generate high manufacturing costs
[0011] In addition, it is difficult to assemble the pads on the aluminum contact support by welding or brazing, as this requires heating the support to a temperature close to its melting point

Method used

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  • Methods for manufacturing an electrical contact pad and electrical contact

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0073] Embodiment 1 (comparative)

[0074] Mixtures of silver powders are prepared having a size comprised between 30 and 80 microns and containing tin oxide, the tin oxide particles being less than 20 microns, the composition being 8% oxide by weight (approx. 12%).

[0075] The powder mixture was fired by cold spraying at 30 bar and 300° C. on a copper plate with a length of 50 mm, a width of 27 mm and a thickness of 1.5 mm. A 2 mm layer was deposited.

[0076] a. The porosity of the deposit does not exceed 3%;

[0077] b. The structure is uniform to the naked eye, but non-uniform under the microscope;

[0078] c. But the composition of the layer obtained does not correspond to the original composition: the oxide loss is about 50%.

Embodiment 2

[0079] Embodiment 2 (invention)

[0080] The powder of tin oxide was coated with silver by CVD to obtain the desired composition by volume (20%). The size of the particles is between 10 and 40 microns. A layer of 1.5 mm was shot by cold spraying on a pre-cut copper and brass UZ15 support (thickness 1.5 mm) under conditions optimized for this particle size. The conditions were 30 bar and 400°C.

[0081] a. The porosity of the deposit is low (<0.5%);

[0082] b. The structure is homogeneous;

[0083] c. The composition of the layer obtained is that of the sprayed powder;

[0084] d. However, expansion annealing showed cracking of the deposit; and

[0085] e. Electrical tests on commercial equipment (3x400VAC, 37A) under AC3 conditions showed unusually high corrosion compared to standard materials obtained by conventional powder metallurgy.

Embodiment 3

[0086] Embodiment 3 (invention)

[0087] According to the method described in US Patent 5,846,288, chemically obtained spongy powders of silver and tin oxides (14% oxide by weight, about 20% by volume) , fired on a preformed copper support (deposited thickness: 3 mm, support: 4 mm). Its particle size lies between 40 and 300 microns.

[0088] a. The porosity of the deposit is less than 0.1%;

[0089] b. The structure is homogeneous;

[0090] c. The composition of the layer obtained is that of the sprayed powder;

[0091] d. Electrical tests on commercial equipment under AC3 conditions (460 amps, 3x400 volts) show lifetimes on the order of typical contacts for this type of equipment. A fracture at the end of life is reported, which is similar to that of the standard material, but shallower.

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Abstract

The present invention relates to a method for manufacturing an electrical contact pad, including a pad mounting and at least one contact layer, and moreover relates to a method for manufacturing an electrical contact, including a contact mounting and at least one contact layer. Said methods include a step of depositing, by means of cold gas dynamic spraying, a first powder onto said pad or contact mounting so as to form said contact layer, said first powder containing at least particles including grains made of at least one refractive material, said grains being built into a matrix made of conductive metal selected from among silver or copper. The invention also relates to the pads and to the electrical contacts obtained in said respective manufacturing methods.

Description

technical field [0001] The invention relates to the field of electrical contacts. It relates more particularly to a method of manufacturing an electrical contact pad and a method of manufacturing an electrical contact, and to an electrical contact pad and an electrical contact obtainable by their respective manufacturing methods. Background technique [0002] So-called "low voltage" electrical contacts, for which the operating range is approximately between 10 and 1,000V and between 1 and 10,000A, are commonly used in the domestic, industrial and automotive sectors, in both DC and AC , for switches, relays, contactors and circuit breakers, etc. [0003] Electrical contacts are made of materials that must meet the following three requirements: [0004] - Low and stable contact resistance to avoid excessive heating when current flows; [0005] - good electrical resistance for welding in the presence of an arc; and [0006] - Low corrosion under arc action. [0007] In ord...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01H1/021C23C24/04
CPCH01H11/048C23C24/04H01H1/025H01H1/023C23C24/08C23C28/023C23C28/021H01H1/021C23C24/085C23C28/027Y10T29/49208
Inventor G·罗兰M·让丹C·布尔戴
Owner METALOR TECH INT