JPS62250135A - Composite electrical contact point material made of ag-sno alloy - Google Patents

Abstract

PURPOSE:To form a composite electrical contact point material of large volume having superior contact resistance by metallurgically uniting plural pieces of Ag-SnO alloy stock to one body and heating the body to precipitate metallic oxides by internal oxidation and to make the grain boundaries of Ag discontinuous. CONSTITUTION:Plural pieces of Ag-SnO alloy stock contg. 1.5-10% Sn, 0.5-5% In and <=0.5% Ni or Co, e.g., sheets, wire rods or granules are combined to a desired shape under pressure. They are united to one body and internally oxidized by heating at a temp. close to the m.p. of Ag to form a composite electrical contact point material made of an Ag-SnO alloy having discontinuous grain boundaries of Ag and contg. very small amounts of oxides of Sn, In and Ni or Co precipitated in the Ag matrix. The contact point material has such characteristics as uniform hardness, a long service life and uniform contact resistance.

Description

Detailed Description of the Invention (a) Technical field The present invention relates to a composite electrical contact material, more specifically, a composite electrical contact material having a plurality of A
The present invention relates to a novel electrical contact material that is made by combining and integrating g-SnO alloy materials.

(b) Background Art A contact material made of an Ag-SnO alloy made by an internal oxidation method was developed by the inventor of the present application and is described in, for example, U.S. Pat. No. 3,933,485 Sl.

Such alloys have metal oxides precipitated within the parent metal by internal oxidation, with tin 1.5-10 tons 11X%, indium 0.5-6 tons i-%, 0.5 tons suspension% The following products are all composed of iron group metals and the balance is silver, and can be suitably used in the invention of the present application.

The inventor of this application repeated the experiment and found such Ag-3n.
It has been confirmed that O-based alloys are equivalent to or superior to Ag-Ca2-based alloys in various properties.

However, the diffusion rate of 11 elements from the outside of Ag-3nO alloy during internal oxidation (e.g., heating at about 700°C in an oxygen atmosphere) is slower than that of Ag-Ca2 alloy, and is only about half that of the latter. There are some drawbacks. Therefore, it takes a long time to internally oxidize an Ag-5n alloy having a relatively large volume or thickness, and the internal oxidation is often not complete.

(c) Disclosure of the Invention By solving these disadvantages that can be said to be unique to Ag-3nO alloys, a comparatively large capacity A-5'
Aiming to advantageously obtain n'O-based alloy joints and materials.
,,i,The second invention has been made.・A plurality of A g- 'S
' n O alloy material - (component: Ag-3n1.5~l
0%-In0.5-5%, Ni or C.

According to the present invention, a composite electrical contact material is obtained by synthesizing silver (0.5% or less) into a desired bulk shape under pressure and heating this at a temperature near the melting point of silver, 960°C.

When synthesizing the plurality of Ag-3nO alloy materials described above, silver,
By synthesizing and heat-treating materials of copper or its alloys, this invention can easily produce composite contact materials of relatively large volume or thickness, using the latter as a base material and clad with Ag-SnO alloy. It is something that can be obtained.

When copper is used as the base member of such a composite contact material, the heat treatment is preferably performed near the eutectic temperature of silver and copper, 779°C.

The thus obtained Ag-SnO alloy electrical contact composite material with or without a base member of silver, copper or their alloys is further hot-rolled or extruded to desired dimensions. It can also be processed into plates or wires. In such a case, the heat treatment described above can be performed simultaneously with hot rolling or extrusion molding.

When I did a durability test, it was found that Ag-3n according to this invention
When an electrical contact made of an O alloy composite has a similar relatively large volume, it has a particularly high capacity compared to a conventional Ag-3nO alloy contact of the same composition obtained by internally oxidizing the whole as a whole. It was confirmed that the contact resistance was excellent.

This is because if a relatively large volume of Ag-5n-0 alloy is internally oxidized as a single unit from the beginning, the internal oxidation will be incomplete as described above, and as a result, the internal oxidation of the contact will be incomplete. This is because while the hardness decreases as the contact wears down, the contact pressure decreases as the contact wears out, increasing the contact resistance, and this increase in contact resistance will eventually cause the contacts to weld. .

On the other hand, since the contact according to the present invention has uniform hardness throughout, it does not have the above-mentioned defects, has a long life, and has a nearly uniform contact resistance throughout its life.
．． It is.

The basis of this invention is listed as follows.

(a)) The metal oxide in the Ag-3nO alloy having a dual composition is stable even at temperatures above 700°C and melting point above 960°C.

(b) The metal oxide dispersed and precipitated in this Ag-SnO alloy is harder than the metal oxide in the Ag-Cdo alloy,
Moreover, its particle size is about 1/1G of the latter.

For this reason, even when the composite contact material of the present invention is rolled or extruded, no change is brought about in the dispersed phase of the metal accumulation in the alloy.

Furthermore, when alloy materials are synthesized under pressure, these fine, hard metal oxides act like wedges between each material, preventing the materials from sliding backwards and making it easier to clean the materials. The contact surface must be kept clean and active.

Such effects are particularly remarkable when the composite contact material of the present invention is made by synthesizing copper as a base member.

(c) The strain that occurs in the alloy composite can be removed by rolling or extrusion near the melting point of silver, and the grain boundaries of silver in the alloy can be discontinuous by hot rolling or extrusion. It has the potential to be effective.

(d) Examples Example 1 Weight ratio: Ag-3n5%-In1.7%-Ni0.3%
The alloy was rolled into a plate of thickness ITS. This board is 60m wide
1 was cut into small plates with a length of 300 cm. This small plate was internally oxidized at 700° C. for 40 hours in an atmosphere of oxygen lθ atm. Both sides of the small plates thus internally oxidized were washed with a 5% aqueous nitric acid solution.

One silver plate of the same size as this small plate and ten of the small plates mentioned above were placed in the cave with the silver plate at the bottom. These plates were synthesized by applying a load of 13"/C112 and heating them at 800°C for 10 minutes. The plates thus synthesized into an integrated composite ingot were preheated at 800°C to a thickness of 2. It was rolled into a plate (2).This plate was punched out to obtain a contact with a diameter of 6+s*.

The performance of the contact of the present invention was evaluated in the A, S, T, and M contact tests in comparison with a contact made by general internal oxidation that has the same dimensions, composition, and structure as the contact of the present invention. When tested, the results were as follows.

Voltage: AC200V Current = 50A Load: Reactor-Pf = 0.2 Temperature 260 times/minute A: 100,000 times Contact pressure crab 100g Unfired 1! 1 contact Number of welds by conventional method
78 Contact resistance 2.0mΩ 3.5mΩ consumption IJ
23 mg 25 mg Example 2 An alloy having the same composition as in Example 1 described above was processed into a wire with a diameter of 2 mm. This wire was cut into short wires with a length of 300+*@. This short wire was
Internal oxidation was carried out for 0 hours. After washing with acid, 4 was made into a bundle of 50 layers in diameter, and hot extruded at a temperature of 800℃ to form a bundle with a diameter of 4.
Six m-layer wires were obtained. After that, while repeating annealing,
This was processed into a tape shape with a thickness of 0.5 mm 111+i14+*a+. On one side of this tape, Cu-
A tape made of Ni (30%) was pressed while being heated at about 850°C. The pressure n-plane had a eutectic structure, ensuring strong pressure bonding.

The thus obtained tape-shaped A g S rt
The O alloy composite contact material has a higher elongation rate than the conventional Ag-SnO contact material made using the general internal oxidation method. had low tensile strength and was prone to cracking, and cracks occurred during cutting.

Example 3 Ag-58%-In3%-NiO,3% by weight
An alloy was made and melted. This was blown away with N2 gas to produce coarse particles with a diameter of 0.1 to 1.51111. After washing this with 0m which was internally oxidized at 700℃ for 6 hours in an oxidizing atmosphere, it was made into a disk with a diameter of 61 mm and a thickness of 2 mm, and the bottom surface had a total of 111 mm.
1/10 m of silver powder was applied, molded using 3 tons, and heated to 900°C.
The material was sintered in an oxygen stream for 3 hours. This was remolded under a load of 5 tons.

Tests have shown that the contacts of the present invention have a contact resistance that is 30-50% lower than similar disc-shaped contacts of the conventional method.

(E) Effects of the Invention As stated in Section 1i71 (a), the metal oxides internally oxidized and precipitated in the entire silver matrix of the alloy material used in this invention are
It does not decompose at temperatures near the melting point of silver. Therefore,
Even if a composite made of a plurality of such alloy materials is heat-treated near the melting point of silver, the E fiJ gold of each alloy material melts without causing any evil to the metal oxide in each alloy material. In other words, there is an outstanding effect of being able to integrate them metallurgically.

Furthermore, as described in (c) above, the grain boundaries of the silver particles can be made discontinuous by hot rolling or extrusion. Therefore, 1.2 exists in continuous segregation along the silver grain boundaries in the alloy material. The continuity of the metal oxide is broken and the metal oxide moves to other parts, and as a result, such segregation disappears and it becomes uniformly dispersed in the alloy material, improving conductivity and fire resistance as a contact material. It's also effective.

Patent applicant: Chugai Electric T-gyo Co., Ltd.; Same as above, Asaga - Itsuki! .

Claims (1)

[Claims] Ag-SnO, a composite of multiple alloy materials with almost the same shape
system alloy electrical contact material, the alloy materials are metallurgically integrated with each other, and the silver base metal of the alloy material is fused so that the silver grain boundaries are discontinuous, and the silver base metal contains metal. The electrical contact material described above has precipitated internally oxidized metal oxides of 1.5 to 10% by weight of tin, 0.5 to 6% by weight of indium, and trace amounts of 0.5% by weight or less of iron group metals.