JPH0449729B2 - - Google Patents

Description

[Detailed description of the invention]

[Detailed Description of the Invention] The present invention relates to a method for manufacturing a composite electrical contact in which the contact material and the backing material, the backing material and the base metal have stable bonding strength, and exhibit stable welding resistance. It is something. In the production of conventional silver-oxide composite electrical contacts, Ag-Cd-Sn, Ag-Cd-Sn,
Because plates of alloys such as Ag-Sn-In-Cd and Ag-Sn-In were punched out into disk shapes after being internally oxidized, a thin layer of oxide existed in the center of the plate thickness. When the thickness of the completed contact decreases during use and the contact surface reaches the thin oxide layer, there is a serious problem of rapid wear and frequent welding. One of the purposes of the present invention is to eliminate the drawbacks caused by using internally oxidized plate material as a material for contacts, and to achieve this purpose, the present invention uses internally oxidized wire material as a material. . When the alloy wire with the above composition is internally oxidized,
An oxide-poor layer also forms, but along the longitudinal centerline of the wire. When this internally oxidized wire is cut into rings, a dilute oxide layer always appears in the center, but this layer accounts for a very small percentage of the entire cross section of the wire. It is clear that the above-mentioned drawbacks of the conventional method can be eliminated by using this sliced wire as a raw material. Another object of the present invention is to use inexpensive copper or copper alloy instead of expensive silver alloy as the backing material for the dot material. This allows the cost of the contacts to be significantly reduced. Still another object of the present invention is to definitively strengthen the bond between the contact material and the backing material, and between the backing material and the base metal. To achieve this objective, when joining by resistance welding, a small amount of organic solvent is injected into the vicinity of the joint surface to generate a reducing gas, and the atmospheric atmosphere during welding is replaced with the reducing gas. As a result, even if a backing material made of copper or a copper alloy, which has a slightly inferior bonding strength as a backing material made of a silver alloy, is used as described above, a sufficiently strong bond can be obtained. This invention was made with attention to the above-mentioned points, and consists of superimposing a disc made of internally oxidized silver-oxide alloy wire cut into rings and a disc made of cut copper or copper alloy wire, and furthermore, When combining the stacked body with a pedestal and joining them using a resistance welder, before applying electricity and heating and joining, an organic solvent such as alcohol is injected into the vicinity of the joint surface.
The air on the overlapping surfaces of each part is replaced with a reducing gas produced by thermal decomposition of organic solvents, so that joining is performed in a reducing atmosphere, and this gas cleans and activates the joining surfaces. The object of the present invention is to provide a method for manufacturing a silver-oxide composite contact which has a stable bonding strength and a stable bonding force. In other words, as shown in Fig. 2, a composite contact material (composite for movable material), which is a combination of a disc made of internally oxidized wire and a disc made of copper or copper alloy wire, is placed between the upper electrode 1 and the lower electrode 2 of a resistance welding machine. After setting the contact material 3 or fixed composite contact material 4), before applying electricity and starting heating bonding, an organic solvent is injected near the overlapping surface of the composite contact material between the two electrodes to remove the surrounding air. First, the organic solvent is decomposed by heating with electricity, and the composite contact material is bonded in a reducing atmosphere to obtain a contact with a more stable bonding force than in the conventional method. Figure 3 shows a rivet type composite contact (6
Or 7) is shown. Also the fourth
As shown in the figure, not only the bonding of the contact material but also the bonding of the contact material and the base metal 5 can be performed simultaneously. Note that the term "disk" here includes not only a disc but also a polygonal plate-like piece. The organic solvent to be injected or dropped near the contact material between the two electrodes is one that has a relatively high vapor pressure at room temperature and easily becomes a reducing gas when heated; specifically, methanol, Alcohols such as ethanol and organic solvents such as acetone can be used. By using these organic solvents, the oxygen partial pressure in the vicinity of the contact material is first reduced, and then the contact materials are bonded in a completely reducing atmosphere through electrical heating, so that the bonding surface and It is understood that the oxidized coating present on the surface to be brazed with the base metal is reduced and the joint surfaces are activated and then joined, resulting in an even tighter joint. Example 1 This example shows a manufacturing example according to the present invention. Ag-SnO ₂ -In ₂ O ₃ -CdO system (composition 89% Ag-
11% oxide) alloy wire φ2.9mm annealed wire,
Each disk was cut out from φ2.9mm Toughpitch copper wire, and the two types of disks were stacked together.
This is pressurized with a compound header machine, and a composite disk with a movable contact of 6φ x 3.0 (1.2) mm taper 12° (with a contact surface of 20R) and a fixed contact of 6.2φ x 2.4 (1.5) mm taper of 12° (flat contact surface) is created. was made using an AC spot welding machine (25KVA) using pure W as an electrode and injecting alcohol near the joint between the electrodes.Then, the molding conditions were set to 7.800A current, 7HZ current, and 0.5Kg/ ^cm2 pressure. A composite disk-type contact was formed in a reducing atmosphere due to thermal decomposition of methyl alcohol, silver-brazed to a base metal by resistance brazing, and subjected to the test described below. Example 2 This example also shows a manufacturing example according to the present invention. Using the same materials as in Example 1 and performing the same operations as in Example 1, Movable contact 6φ x 1.5 (0.8) to 3φ x 1.5mm taper 12° (with contact surface 20R) Fixed contact 6.2φ x 1.5 (0.8) A composite rivet with ~3φ x 1.5mm taper 12° (contact surface flat) was made and set between the electrodes (in this case, an alloy of 20% Ag and 80% W was used) in the same manner as in Example 1, and the gap between the electrodes was After injecting ethyl alcohol into the vicinity of the joint, a composite contact was formed by electroforming, which was silver-brazed to a base metal and subjected to the test described below. Example 3 This example also shows a manufacturing example according to the present invention. The composite rivet shown in Example 2 was made using the same materials as in Example 1 and in the same manner as in Example 1, and the composite rivet, copper base metal, and silver solder ABG-1 were used as an electrode (using pure Mo). After injecting acetone into the vicinity of the joint between the poles, molding of the composite contact and silver brazing between the contact and the base metal were performed at the same time under the same molding conditions as in Example 1. provided. Example 4 This example also shows a manufacturing example according to the present invention. Internally oxidized Ag-CdO-SnO ₂ system (composition 82.5%
Ag-16.5%Cd-1.0%α) alloy wire was used as the contact material. In other words, Ag and Ni are approximately
Melt at 1500℃, then lower the temperature to 1000℃, add 50%Ag-50%Cd Ag-Cd master alloy, Sn, cast, heat extrusion, and then plastic working.
A wire rod of 2.9 mmφ was heated at 750℃ in an internal oxidation furnace.
A silver-oxide wire was obtained by holding it in an oxygen atmosphere of 3 atm for 120 hours, and a disc obtained by cutting this wire into rings and a disc obtained by cutting a 2.9 mmφ wire of Tuff Pitch copper wire into rings were stacked together. A composite rivet of the same shape as the composite rivet shown in Example 2 was made using a composite header wire, and then set between the electrodes (in this case, 95% W and the remaining Ni-Cu alloy) in the same manner as in Example 1. After injecting butanol near the joint between the poles, a composite rivet contact was formed by electroforming, and this was silver-brazed to the base metal. It was used for the test described below. Comparative Example 1 This example shows an example of manufacturing a conventional contact material. An alloy having the same composition as in Example 1 was used as a contact material to obtain a contact material having a width of 40 mm and a thickness of 10 mm after processing, and a pure silver plate of about 1 mm in thickness was thermocompression bonded to one side of the contact material to form a silver layer for brazing. Next, after processing this material and making it into a thin plate, 6
mmφ and 6.2 mmφ contacts, and held in an internal oxidation furnace at 700° C. in an oxygen atmosphere of 3 atm for 48 hours to produce a silver-oxide based punched disc type contact as shown below. Movable contact 6φ x 1.5mm (with contact surface 20R) Fixed contact 6.2φ x 1.2mm (contact surface flat) These were silver-brazed to the base metal using resistance brazing and used for the tests described below. Comparative Example 2 This example also shows an example of manufacturing a conventional contact material. Using an alloy with the same composition as in Examples 1 to 3, a composite rivet type contact having the same shape as in Examples 2 to 3 was formed with a burr-shaped burr on the outer periphery almost all the way around during header forming. It was manufactured using a manufacturing method that applies sufficient pressure, deburred, and heat treated to create a composite rivet type contact. This was silver-brazed to the base metal using resistance brazing, and was subjected to the test described below. Comparative Example 3 This example also shows an example of manufacturing a conventional contact material. Alloy with the same composition as Example 4 (Ag-CdO-SnO ₂
The same operation as in Comparative Example 1 was carried out to obtain silver
An oxide-based stamped disk type contact was fabricated as shown below. Movable contact 6φ x 1.5mm (with 20R contact surface) Fixed contact 6.2φ x 1.3mm (flat contact surface) Resistance brazing these to the base metal using silver brazing. It was used for the test described below. Comparative Example 4 This example also shows an example of manufacturing a conventional contact material. An alloy having the same composition as in Example 4 was used as a contact material, and after processing, a contact material having a width of 40 mm and a thickness of 10 mm was obtained.A pure silver plate of approximately 1 mm was thermocompression bonded to this surface to form a silver layer for brazing. Next, contact shapes of 6 mmφ and 6.2 mmφ were punched, and these were kept in an internal oxidation furnace at 750°C in an oxygen atmosphere of 3 atm for 48 hours to create silver-oxide punched disk-type contacts, and further 6φ×0.8 mm and 6.2φ×
A 0.8mm base metal was brazed to create a laminated disk-type contact as shown below. Movable contact 6.0φ x 1.6 (0.8) mm (with contact surface 20R) Fixed contact 6.2φ x 1.6 (0.8 mm) (contact surface flat) Silver brazed to the base metal using resistance brazing.
It was used for the test described below. Performance test 1 This test evaluates the joint strength and contact hardness. The room temperature hardness and room temperature shear strength of each contact material produced in the above manufacturing example was measured. The results are shown in Table 1. It can be seen that the contact material manufactured according to the method of the present invention has a more stable bonding force than the contact material listed as a comparative example. Performance Test 2 This test evaluates the amount of wear, contact resistance, and weldability. That is, voltage AC220V, current 115A, power factor, 0.5 to check the performance of each contact.
It was assembled into a three-phase 5.5KW rated electromagnetic switch and tested for switching, and the results are shown in Table 2. The contact resistance before and after the test was also measured.

【table】

[Table] Yes.

[Table] As is clear from the test results, the composite electrical contacts manufactured by the method of the present invention
−SnO ₂ −In ₂ O ₃ −20% to 50% less silver than CdO-based punched disk type contacts, and approximately 2 times longer lifespan.
Double the welding and abrasion resistance. In other words, if an organic solvent such as alcohol is injected into the contact material set between the electrodes or in the vicinity of the contact material and the brazing base, and then electrically heated and bonded, superior contact performance can be achieved compared to contacts manufactured using conventional methods. is expected to have great industrial effects.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the lower electrode on which the composite contact material is set, Figures 2 and 3 illustrate the heat molding process for disk-type composite contacts and rivet-type composite contacts, respectively, and Figure 4 shows the rivet with base metal. This figure shows the heat molding process of a molded composite contact. In each of the above drawings, a indicates a movable contact, b indicates a fixed contact, and c and d indicate the state in which the movable and fixed contacts are set on the base metal. In Figures 1 to 4: 1: Upper electrode, 2: Lower electrode, 3: Movable disk-type contact, 4: Fixed disk-type contact, 5: Base metal, 6: Movable rivet-type contact, 7: Fixed Rivet type contacts. FIG. 5 shows an enlarged cross-sectional photograph of the contact of Example 1 after a 350,000-cycle opening/closing test, and FIG. 6 shows an enlarged cross-sectional photograph of the contact of Comparative Example 1 after a 150,000-cycle opening/closing test.

Claims (1)

[Claims] 1. A method for manufacturing a composite electrical contact combining a contact material and a lining material, which comprises discs obtained by slicing internally oxidized silver-oxide alloy wire and copper or copper. The disks obtained by cutting the alloy wire into rings are stacked together, and the stacked body is inserted between the electrodes of a resistance welding machine, and at least enough decomposition gas to displace the air on the overlapped surfaces of the stacked body is applied. A silver-oxide composite electrical contact with stable bonding strength between a contact material and a backing material, which is characterized by injecting the generated organic solvent around the laminated body and then immediately applying pressure and current to the laminated body. manufacturing method. 2. A method for manufacturing a composite electrical contact combining a contact material, a backing material, and a base metal, in which a disk obtained by slicing internally oxidized silver-oxide alloy wire material, and a disk obtained by slicing copper or copper alloy wire material into rings. Layer the disk obtained by above and the base metal material in this order, insert this stacked body between the electrodes of a resistance welding machine, and remove at least enough air to displace the air on each overlapping surface of the stacked body. Bonding of a contact material and a backing material, and of a backing material and a base metal material, characterized by injecting an organic solvent that generates a large amount of decomposed gas around the stacked body, and then immediately applying pressure and electricity to the stacked body. A method for producing a silver-oxide composite electrical contact with stable force.