DE2432335A1 - ELECTRICAL CONTACT MATERIAL - Google Patents

Description

Patent Attorneys Liedl, Dr. Pontani, Nöth, Zeitler 2432335 Munich 22, Steinsdorfstrasse 21-22, phone 089/29 84 62

A 6803

Sumitomo Electric Industries, Ltd. 15, 5-chome, Kitahama, Higashi-ku, Osaka / JAPAN

Electrical contact material

The invention relates to an electrical contact material of the silver oxide-indium oxide type.

The invention relates to electrical contacts and is more particularly concerned with an electrical contact of the silver oxide-metal oxide type made by the internal oxidation process and having improved electrical properties.

j / G 409885/0981

Among the silver oxide-metal oxide type contacts made by internal oxidation, silver oxide-cadmium oxide contacts are widely used. Since the contacts made of silver oxide-cadmium oxide have a have uniformly low contact resistance as well as welding and arc erosion resistance, is their application in relays and contactors or short-circuit switches for small and large currents. However, the use of cadmium in the manufacture of the contact material is harmful to the health of the workers.

As cadmium-free contact materials of the silver type, silver-tungsten, Silver carbide-tungsten carbide, silver-nickel and silver-graphite can be used, but the contact materials are silver-tungsten and Silver carbide-tungsten carbide disadvantageous compared to the silver oxide-cadmium oxide contact material, because the frequent opening and closing The increase in contact resistance in the air also leads to an increase in the temperature of the contact surfaces, while the silver-nickel and silver-graphite contact materials have less good welding strength and resistance to arc erosion in the range of medium to high currents. That is why the areas of application and conditions of use of these contact materials in contacts for switches surrounded by air. Could be a contact with high welding and arc erosion resistance as well as a low contact resistance, which does not contain cadmium, can be found, see above this material would be of great use to industry. So far, however, no alloy of the same quality has been found as that of the silver oxide-cadmium oxide contact.

The invention is based on the object of providing an electrical contact with to produce improved electrical properties from Silbero ^ dd metal oxide. As a further task a cadmiumfreten B & 3ialsktmate> lsi of the silver oxide-metal oxide type, w © lelms ildi with dam

6803 409885/0 * 81

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Silver oxide-cadmium oxide contact material can be compared favorably. Further A method is to be provided for the production of a cadmium-free contact material of the silver oxide-metal oxide type by internal oxidation.

The object is achieved according to the invention by an electrical contact material of the silver oxide-iridium oxide type, which is produced by the internal oxidation of 6-15% by weight of iridium, 0.2-8% by weight of tin and / or 0.01% by weight. 1 wt -.% of magnesium and the remainder consisting of silver alloy. If necessary, this alloy can also contain 0.01-1% by weight of nickel.

It has been found that a silver oxide-indium oxide contact material through the addition of tin oxide and / or magnesium oxide has excellent properties obtained and that this contact material is preferably to be produced by the so-called internal oxidation process. Li some cases nickel oxide can also be added. As is known in the art, there are advantages of the internal oxidation process in that an oxide is uniformly and finely dispersed in a metallic structure to strengthen the structure and increase heat resistance raise. This method is mainly used in the production of silver oxide-cadmium oxide contacts according to the prior art.

In a preferred embodiment of the invention, the silver oxide-iridium oxide contact material is used produced by the internal oxidation of 6-15% by weight indium, 0.2-8% by weight tin and the rest r made of silver alloy.

In a further preferred embodiment of the invention the silver oxide-indium oxide contact material produced by the internal

6803 409885/0981

Oxidation of a from 6-15 wt -.% Indium 0.01 - 1 wt -.% Magnesium, 0.01-1 wt -.% Nickel and the remainder consisting of silver alloy.

The essential feature of the invention is to dissolve indium and at least one of the metals tin and magnesium, which have less harmful effects than cadmium, in silver in order to produce a corresponding alloy and then to oxidize it internally, as a result of which a silver oxide-indium oxide contact material is obtained, the one also after repeated opening and closing of the contact still has stable contact characteristics and its current-carrying capacity is essentially the same as that of a state-of-the-art silver oxide-cadmium oxide contact, as can be seen from the experimental examples.

The most notable effect from the addition of indium as well Tin and / or magnesium to silver and a subsequent internal oxidation is the increase in the welding and arc erosion resistance of a contact. If, on the other hand, an internally oxidized alloy is made If silver and indium, silver and tin, silver and magnesium or silver and nickel are used, the welding or arc erosion of a contact is so great that the contact cannot be used as a switch for medium and higher currents is suitable. The effect according to the invention is achieved by adding ihdium to silver with tin and / or magnesium and optionally obtained nickel with subsequent internal oxidation.

The amount of lidium to be dispersed in silver prior to internal oxidation is usually 6-15% by weight, which makes the contact properties effective. To be added to such a silver-ihdium alloy in order to improve the contact properties The amount of tin is effective in the range 0.2-8% by weight. Are

6803 409885/0981

If the quantities of indium and tin are too large, rolling or internal oxidation is no longer possible. The composition range within which internal oxidation is possible depends on the oxidation conditions. So is, for example, at an oxidation temperature of 720 C under an oxygen partial pressure of 0.21 atm at 10 wt -.% Indium, the upper limit of the amount of tin at about 8 wt -.%. Since in one of Γ

Silver-tin existing binary system, the maximum concentration of the tin usually about 5 wt -.% Is, it means that the common addition of indium and tin is used to increase the maximum concentration of the tin. Within the range given above, the silver oxide-indium oxide-tin oxide contact is essentially as good as the prior art silver oxide-cadmium oxide contact and the current carrying capacity or load capacity is not reduced.

In a further embodiment of the invention, the silver-indium alloy or silver-indium-tin alloy to be 0.01-1 wt -.% Of magnesium and optionally 0.01-1 wt -.% Nickel added, after which the internal oxidation is carried out so that the electrical properties of the contact are improved. In comparison to indium, as stated above, magnesium produces this effect in relatively small amounts, preferably in a ratio of 0.05-0.8% by weight. If the amounts of indium and magnesium are too large, the alloy becomes unstable during rolling or internal oxidation. If, on the other hand, the amount of magnesium is too small, the above-mentioned effect hardly occurs and therefore at least 0.01% by weight of magnesium is required. Within the range given above, the contact is essentially as good as the state-of-the-art silver oxide-cadmium oxide contact and the current carrying capacity or load capacity is,

not decreased.

6803 409885/0981

The pronounced effect obtained by adding magnesium with optionally nickel to an alloy of silver-indium or silver-indium-tin and subsequent internal oxidation is that of a large increase in the hardness of the alloy. For example, in the case of an alloy of silver-indium was 10%, the Vickers hardness (Hv 5 kg) 110 - 120. These increased by the addition of 0.1 wt -.% Magnesium, 0.1 wt -.% Magnesium, and 0 1 wt -.% nickel and 0.5 wt -.% magnesium and 0.5 wt -.% nickel and subsequent internal oxidation at 170 or 175 and 215. This will substantially improve the welding and arc erosion resistance as seen from the test of the contact properties given below.

The mentioned silver-indium alloys according to the invention can additionally small amounts of other elements, such as manganese, iron, cobalt, molybdenum, lanthanum, zirconium, and aluminum, that are being achieved are not detrimental to the object of the invention, prior to internal oxidation contain.

The invention is intended to explain the invention in more detail using the following experimental examples. be tert.

Experimental example 1

There were 89 wt -.% Silver, 10 wt -.% Indium, and 1 wt -.% Tin melted, poured, and rolled to a thickness of 1.5 mm. The resulting layer was internally oxidized at 700 ° C. for about 100 hours in an oxygen atmosphere, cut into a sample of 5 × β × 1.5 mm, and brazed to a copper base. The sample was then subjected to a guiding and closing test using an ASTM contact tester with 100 V AC, 30 A and a load resistance

6803 409885/0981

Voltage drop between contacts 20 - 40 mV, causing it proved that the contact of the invention was essentially the same Had current carrying capacity or load capacity, like the prior art silver oxide-cadmium oxide contact.

Experimental example 2

There were 88 wt -.% Silver, 10 wt -.% Indium, and 2 wt -.% Tin melted, poured, and rolled to a thickness of 1.5 mm. The resulting layer was internally oxidized at 700 ° C. for about 100 hours in an oxygen atmosphere, cut into a sample of 5 × 6 × 1.5 mm, and brazed onto a copper pad. Then, at AC 220 V (60 Hz), a contact pressure of 500 g, and using a load resistor, a current of 2,500 A (peak value) was passed three times in 1.5 cycles while the welding forces were measured at the same time. The contact according to the invention had welding forces of 100 g or 250 g and 300 g, which are accordingly less than 1 kg, and looked flawless. This property is similar to the prior art silver oxide-cadmium oxide contacts.

Experimental example 3

There were 84 wt -.% Silver, 10 wt -.% Indium, and 6 wt -.% Tin melted, poured, and rolled to a thickness of 1.5 mm. The resulting layer was internally oxidized at 700 ° C for about 200 hours in an oxygen atmosphere, cut into a sample of 5.x β 1.5 mm and brazed onto a copper base. Thereafter, a current of 2,500 A (peak value) was passed through three times in 1.5 cycles at 220 V alternating current (60 Hz) and a contact pressure of 500 g and with a load resistance, the welding forces being measured at the same time. The contact according to the invention had welding forces of 200 g or 100 g and 100 g, which were accordingly less than 1 kg, and looked flawless.

6803 409886/0981

Experimental example 4

There were 91 wt -.% Of silver, 8 wt -.% Indium, 0.5 wt -.% Magnesium and 0.5 wt -.% Nickel is melted, poured, and rolled to a thickness of 1.5 mm. The resulting layer was internally oxidized at 720 ° C. for about 100 hours in an oxygen atmosphere, cut into a sample of 5 × 6 × 1.5 mm, and brazed onto a copper base. The sample was then subjected to an opening and closing test with an ASTM contact test device at 100 V AC, 30 A and using a load resistor. After performing the switching process 10,000 times, the voltage drop between the contacts with a current of 30 A alternating current was 20-45 mV, which showed that the contact according to the invention had essentially the same current carrying capacity or load capacity as the silver oxide corresponding to the prior art -Cadmium Oxide Contact.

Experimental example 5

There were 89.6 wt -.% Silver, 10 wt -.% Indium, 0.2 wt -.% Magnesium and 0.2 wt -.% Nickel is melted, poured, and rolled to a thickness of 2 mm. The resulting layer was internally oxidized at 720 ° C for about 150 hours in an oxygen atmosphere, cut into a sample of 10 10 χ 2 mm (sample e), attached to a 60 amp frame electromagnetic contactor, and then at a voltage of 220 V alternating current, a current of 370 A, a power factor of 0.5 and a switching frequency of 180 times per hour were subjected to a contact property test.

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Similar contact property tests were performed on contacts made from alloys of

a) silver-10 % indium-0.2 % magnesium,

b) silver-10 % indium-1% tin,

c) silver-10% indium-1% tin-0.02 % magnesium,

d) silver-10% indium-1% tin-0.02% nickel, $

f) silver-10% ihdium-1 % tin-0.02% magnesium-0.02% nickel and, for comparison,

g) silver-13 % cadmium, h) silver-10 % indium and

i) silver-10% indium-0.2% nickel,

all of which had undergone internal oxidation. The burn of these contacts and the voltage drop between the contacts Opening and closing 10,000 times is as follows:

sample

Burn-off Voltage drop 355 mg 115 mV 350 mg 110 mV 340 mg 115 mV 345 mg 110 mV 300 mg 105 mV I 330 mg 115 mV 500 mg 105 mV 550 mg 123 mV 430 mg 120 mV

a) Ag-In Oxide-Mg Oxide

b) Ag-Ih Oxide-Sn Oxide

c) Ag-Ih Oxide-Sn Oxide-Mg Oxide

d) Ag-Ih Oxide-Sn Oxide-Ni Oxide

e) Ag-In Oxide-Mg Oxide-Ni Oxide

f) Ag-In Oxide-Sn Oxide-Mg Oxide-Ni Oxide 330 mg

g) Ag-Cd oxides (for comparison). h) Ag-Bi oxides (for comparison)

i) Ag-Bi Oxide-Ni Oxide (for comparison) 430 mg

measured with 150 A alternating current. The contact document was also measured.

As can be seen from these results, the present invention showed Contacts have a low level of burn-off.

409885/0981

Experimental example 6

There were 88.6 wt -.% Silver, 11 wt -.% Indium, 0.2 wt -.% Magnesium and 0.2 wt -.% Nickel is melted, poured, and rolled to a thickness of 2 mm. The resulting layer was internally oxidized into one at 720 ° C. for about 150 hours in an oxygen atmosphere

Sample of 5x6x2 mm cut, brazed on a copper base and with alternating currents at 220 A, 3,000 A and a power factor of 0.4 subjected to a power cut-off test.

Similar current cut-off tests were carried out on contacts made from alloys of silver-11 %, ihdium-0.2%, magnesium and, for comparison, silver-11%, fiidium and silver-13 % cadmium. The alloys had been subjected to internal oxidation. For each, the power cut was carried out twice and the arc erosion was observed.

The E alloys of the invention
oxide and silver oxide-magnesium oxide-nickel oxide and the comparative alloy of silver oxide-cadmium oxide showed a stable appearance. The alloy of silver oxide-indium oxide showed a large amount of arc erosion, in particular a large amount of end piece burn-off.

Experimental example 7

There were 87 wt -.% Silver, 6 wt -.% Indium, and 7 wt -.% Tin melted, cast and then rolled mm to a thickness of 1, 5. The resulting layer was internally oxidized at 700 C for about 200 hours in an oxygen atmosphere, cut to a sample of 5 × 6 × 1.5 mm, brazed to a copper base and, under the same conditions as in experimental example 2, a measurement of the welding force t subjected. The welding forces were 280 g or 10 g and

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Experimental example 8

There were 92.6 wt -.% Silver, 6 wt -.% Indium, 0.7 wt -.% Magnesium and 0.7 wt -.% Nickel is melted, cast and then rolled to a thickness of 1.5 mm. The resulting layer was internally oxidized at 700 ° C. for about 200 hours in an oxygen atmosphere, cut into a sample of 5 κ β 1.5 mm, brazed to a copper pad and a measurement of the welding force under the same conditions as in the experimental example 2 subjected. The measured welding forces were 400 g, 300 g and 550 g, respectively.

Experimental example 9

There were 84.9 wt '% silver, 15 wt -..% Indium, 0.05 -.% Magnesium and 0.05 wt -.% Nickel is melted, cast and then rolled to a thickness of 1.5 mm. The resulting layer was internally oxidized at 700 ° C. for about 400 hours in an oxygen atmosphere, cut into a sample of 5 χ β 1.5 mm, brazed to a copper base, and measurement of the welding force under the same conditions as in the experimental example 2 subjected. The measured welding forces were 400 g, 260 g and 550 g, respectively.

Experiment example 10

84.8% by weight of silver, 15% by weight of indium and 0.2% by weight of Tin melted, poured, and then repeatedly rolled and annealed to give a thickness of 1.5 mm. The resulting layer was annealed at 700 ° C for one hour in a nitrogen atmosphere, washed with a 50% aqueous solution of nitric acid, internal oxidation at 700 ° C for about 300 hours in an oxygen atmosphere subjected, cut to a sample of 5x6x1.5 mm, brazed onto a copper pad and then a measurement of the

409885/0981

Voltage drop between contacts under the same conditions as in Experimental Example 1. After 10,000 switching operations With a current of 30 A alternating current, the voltage drop between the contacts was 30-80 mV.

Experimental example 11
There were

a) 91 wt -.% silver, 7 wt -.% indium, and 2 wt -.% tin,

b) 90.98 wt -.% silver, 7 wt -.% indium, 2 wt -.% tin and 0.02 wt -.% magnesium,

c) 90.98% by weight of silver, 7% by weight of indium, 2% by weight of tin and 0.02 % By weight nickel and

d) 90.96 wt -.% silver, 7 wt -.% indium, 2 wt -.% tin, 0.02 wt -.% magnesium and 0.02 wt -.% nickel

each melted, poured and then rolled out to a thickness of 2 mm. The resulting layers were subjected to internal oxidation at 700 ° C for about 200 hours in an oxygen atmosphere, cut into samples of 10 10 χ 2 mm and then subjected to tests similar to those in test example 5. The erosion of these contacts and the voltage drop between the contacts after 10,000 switching operations was as follows:

Sample burn-off voltage drop

a) Ag-Ih Oxide-Sn Oxide 450 mg 100 mV

b) Ag-Ih Oxide-Sn Oxide-Mg Oxide 430 mg 105 mV

c) Ag-Ih Oxide-Sn Oxide-Ni Oxide 420 mg 110 mV

d) Ag-In Oxide-Sn Oxide-Mg Oxide-Ni Oxide 400 mg 115 mV

measured with 150 A alternating current. The contact pad was also measured.

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As can be seen from the experimental examples, have the invention Contacts of the silver oxide-indium oxide-tin oxide and silver oxide-ihdium oxide-magnesia type excellent resistance to contact erosion, welding and arc erosion, as well as also have excellent current carrying capacity or load capacity and are therefore useful in industry. For use by shooters, Short-circuit switches or air-circuited breakers are these i-

Contacts are therefore just as or better suited than those of the state of the art Technique corresponding silver oxide-cadmium oxide contacts.

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Claims (4)

Claims Electrical contact material of the silver oxide-lithium oxide type by the internal oxidation of an alloy consisting of 6-15% by weight indium, 0.2-8% by weight tin and the remainder of silver. 2. The electrical contact material of the type silver oxide lhdiumoxid produced by the internal oxidation of from 6-15 wt -.% Indium, 0.2-8 wt -.% Tin 0.01 - 1 wt -.% Of magnesium and / or Copper and the remainder of the alloy consisting of silver. 3. An electrical contact material of the type silver oxide lhdiumoxid produced by the internal oxidation of from 6-15 wt -.% Indium, 0.01-1 wt -.% Of magnesium and the remainder consisting of silver alloy. 4. The electrical contact material of the type silver oxide lhdiumoxid produced by the internal oxidation of from 6-15 wt -.% Indium 0.01 - 1 wt -.% Magnesium 0.01 - 1 wt -.% Nickel and the remainder of Existing silver alloy. if 03 8 SS / 03 & 1