DE1266983B - Contact material - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

Number:
File number:
Registration date:
Display day:

C 22c

German class: 40 b -9/00

1266 983
S 54576 VI a / 40 b August 1, 1957 April 25, 1968

In the case of automatic switches, especially in the case of miniature circuit breakers, those made from the previously known contact materials are established, occurs in the event of short-circuit shutdowns or when the contacts are open are closed in the event of a short circuit, often a welding of the contacts. This can lead to malfunctions the switch lead.

There are sintered contacts from a binary system that is miscible in the liquid state, namely a chromium-tin alloy ίο content of 1 to 10 ° / _0, known and further ternary alloys, consisting of 1 to lO ° / o with a tin cobalt, 1 to 10 ° / ₀ cadmium, the remainder being copper, interlocking with solubility of the three components, and compound formation between the components.

The subject of the invention is a contact material made of at least two metal components - with the exception of copper-lead composites produced in accordance with patent 1087 813 - in which no welding occurs under the above-mentioned conditions. It is therefore ideal for automatic switches, especially for miniature circuit breakers. In the contact material according to the invention, at least two metal components have limited miscibility in the liquid state, and one of these, namely lead (Pb), thallium (Tl), bismuth (Bi), indium (In), tin (Sn) or cadmium ( Cd), has a contact material in the temperature range between 200 and 400 ^{° C}

Applicant:

Siemens Aktiengesellschaft, Berlin and Munich, 8520 Erlangen, Werner-von-Siemens-Str. 50

Named as inventor:

Dr. techn. habil. Horst Schreiner, 8500 Nuremberg; Helmut Iwan, 8400 Regensburg

liquid phase, and the proportion of this metal component is 5 to 20%, preferably 10%, measured in the following combinations:

Pb with Al, Fe, Co, Ni and / or Cu, Tl with Al, Fe, Co, Ni and / or Cu, Bi with Al, Fe and / or Co,
In with Al,
Sn with Co,
Cd with Al.

In detail, the melting points for these possible combinations are given below in brackets of the metals concerned.

Component with
liquid phase
between 200 and 400 ⁰ C with liquid With the component
Phase between 200 and 400 ⁰ C
component Co Ni
(1440) (1452) mixable • Pb
(327) Al
(660) Fe
(1530) Co Ni
(1440) (1452) Cu
(1083) Tl
(302) Al
(660) Fe
(1530) Co
(1440) Cu
(1083) Bi
(271) Al
(660) Fe
(1530) In
(158) Al
(660) Sn
(231) Co
(1440) CD
(321) Al
(660)

The excellent suitability of the contact material liquid phase up to relatively low temperatures

according to the invention for the above 50 temperatures in the vicinity of the contacts is maintained,

Applications is based on the fact that the so that during a relatively long time

Current load of the contact material, the contacts are restored with a small opening force

809 540/351

can be separated. This effect is already achieved if only one of the contacts is made of the material according to the invention and the mating contact made of a different contact material, e.g. B. made of copper, consists. Accordingly, in the case of contacts with double interruptions, it is sufficient if either the movable one Bridge or the two fixed contacts made of the contact material according to the invention are.

The metal component, which has a liquid phase between 200 and 400 ° C, can be in the higher-melting one Component to be stored; but it can also be the other way round. In both cases it is an embedding composite. It is also possible that the contact material forms an interpenetrating composite material in which both components are interconnected scaffolds form that are spatially nested.

In the contact material according to the invention, if, for. B. Iron is chosen as a component, the lead, thallium or bismuth surface may be broken up by iron particles. The effective The contact surface is thus formed, for example, by a lead-iron surface. Such a material can be used for certain demands and is extremely inexpensive, which is also true for the metals aluminum, Cobalt and nickel applies, the last two metals in particular then being technical When it comes down to it, we are interested in contact materials with higher hardness (based on copper) to manufacture.

The benefits of such contacts are from the table below for aluminum-based contacts with a Content of 5% lead »thallium, bismuth, indium or Cadmium can be seen. For this purpose, the alloys Al-Bi 95: 5, Al-Pb 95: 5 and Al-Cd 95: 5 the contact resistances when new, the switched contacts and after the opening of welding bridges measured. In addition, the welding current limits at 3.5 kp contact load and the opening forces of the weld bridges formed were measured. The corresponding properties of electrolytic copper and pure silver contacts are given as a comparison.

composition Contact resistance
in new condition
with friction component
Rk ■ ΙΟ ⁵ (Ω) Welding current
limit J
(A) Contact resistance
after the stream
passage
4 periods at 50 Hz
Rk ■ ΙΟ ⁵ (Ω) Opening
by virtue of P
(kp) Contact resistance
After opening
of contacts
Rk ΙΟ ⁵ (Ω) Al-Bi 95: 5
Al-Pb 95: 5
Al-Cd 95: 5
Ecu
Ag 9.0 maximum
Minimum 5.2
Mean 6.9
Maximum of 20.0
Minimal 9.3
Medium 12.5
31.0 maximum
Minimum 12.0
Mean 21.5
8.0 maximum
Minimum 5.6
Medium 6.7
Maximum of 7.0
Minimal 4.4
Mean 5.7 (7240)
6800
(3840)
3410
(2980)
2530
(5960)
5530
(7450)
7030 20th
5
11.1
7.8
5.3
6.5
15th
6.8
8.5
4.4
3.2
3.7
2.1
1.8
2.0 0.05
0
0.008
3.1
0
1.9
3.0
0
0.86
0.7
0
0.13
3.3
0
0.87 18th
9
12.2
65
14th
30th
70
13th
28.3
59
9.6
22.1
3.0
1.9
2.2

Opening forces occurred for the welding currents in brackets > 3.5 kp.

Thus, the contact resistances of the contacts are not closed when they are new and after switching to aggressive atmosphere within reasonable limits. The welding current limits of the specified Alloys are also quite cheap compared to Ε-copper. The aluminum alloys are due of welding current measurements in a non-corrosive atmosphere are suitable as contact materials. Also in These alloys are in a corrosive atmosphere with a suitable structural design of the switchgear and suitable with a corresponding friction component when closing the contacts. At the friction closing the surface layers are destroyed and a metallic contact is guaranteed. Of the higher contact resistance requires a higher contact load in order to be portable for a switching device Warming to take into account. Thus, contacts made from aluminum alloys according to the invention are in particular also for frequently switching switching devices that have to work in a corrosive atmosphere, well suited.

The production of the contact material according to the invention can be on the melting route or on the sinter way. The latter method is particularly advantageous because the contact material according to the invention is difficult to deform when cold; the sintering process enables Manufacture of finished molded parts. Another advantage of the contact material according to of the invention is its resistance to oxidation. This is based on the relatively high vapor pressure the low-melting metal component, which has the consequence that when the Metal vapor forming a liquid phase protects the contact surface from oxidation. The contact surfaces therefore retain a shiny metallic appearance after heavy loads. The prevention the formation of surface oxide layers is therefore

especially important because this causes undesirable increases in the contact resistance in the contact area be avoided.

Claims (2)

Patent claims: 1. Contact material, in particular for circuit breakers, which consists of at least two metal components - with the exception of copper-lead composites produced in accordance with patent 1087 813 - characterized in that at least two metal components have limited miscibility in the liquid state and one of these, namely lead ( Pb), thallium (Tl), bismuth (Bi), indium (In), tin (Sn) or cadmium (Cd), has ^{a liquid phase in the temperature range between 200 and 400 0} C and the proportion of this metal component is 5 to 20% , preferably on 10%, in the following combinations: Pb with Al, Fe, Co, Ni and / or Cu, Tl with Al, Fe, Co, Ni and / or Cu, Bi with Al, Fe and / or Co,
In with Al,
Sn with Co,
Cd with Al. 2. Contact material according to claim 1, characterized in that it is on the melting or Sinterwege is made. References considered:! 5 United States Patent Nos. 2145 792, 2154 700; M. H a η s e n, "The Structure of Two-Material Alloys", 1936, pp. 551 and 1087. Older patents considered: ao German Patent No. 1 087 813. 809 540/351 4 68 © Bundesdruckerei Berlin