JPS58502154A - Light corrosion resistant contact - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Light corrosion resistant contact This invention relates to metal or alloy bodies containing one or more corrosion resistant inlays. Book The invention particularly relates to objects of the type from which corrosion-resistant electrical contact elements are made and to objects made from the objects. This invention relates to electrical contact elements.

The "electrical contact element" shown up to this point and hereinafter shown in this specification is electrically means an electrical conductor, the electrical conductor supporting at least one layer of electrically conductive material; and/or a region of the material, the or each layer and/or region being electrically conductive. What constitutes the physical contact zone? Generally such electrical conductors are pressed or or formed from a sheet of metal or alloy layers by stamping. Said sea The sheets or layers are inlaid with metals or alloys forming electrical contact zones (1nla). id) may be used. Additionally or alternatively, the surface of the sheet or layer or its One or more areas may be coated with a contact zone metal or alloy.

By the "electrical contact zone" hereinafter indicated and hereinafter referred to in the specification said means the part of an electrical conductor that is applied in mechanical contact with the with the same zone of other electrical contact elements or with other electrical conductors suitably arranged. Make electrical connections with electric bodies.

By means of the ``corrosion-resistant electrical contact element'' hitherto shown and hereafter shown in this specification, means an electrical contact element defined up to now, at least the electrical contact zone is resistant. It has eating habits.

Next, if I may say so, an electrical contact element is sometimes simply referred to as a "contactor" or sometimes as a contact. simply called. Similarly, electrical contact zones are sometimes referred to as "contact zones" and sometimes simply electrical contact zones. "contact point".

The electrical conductor referred to in the electrical contact element defined above is often an elastic elongate one common shape for electrical contact elements; contact zone consisting of one layer of electrically conductive corrosion-resistant metal or alloy applied to the material It is made of phosphor bronze with a rear end. Often the arm is slightly machined in the contact zone However, the effective part of the contact zone is the part of the hemispherical or part-spherical pore expansion. other In this arrangement, the end of the contact zone of the arm is deformed into a round or partial cylindrical shape, thereby causing Therefore, the effective part of the contact zone is the outer curved surface of the cylinder or partial cylinder.

Two contact elements of the type hitherto described are often used together to form an opposing contact pair. and an electrical connection is made between them and a metal tongue, for example, between the contacts. This is done by sliding the each contact carries the tongue. An alternative arrangement is that the two arms are metal. or composed of a piece of alloy. In this case an arc with mutually related contact zones The system may also be considered as constituting a single electrical contact element.

This arrangement is of course just one possible arrangement that could be used, but most In which cases, common to all of them, do they actually connect electrical circuits to each other or to other alloy bodies? Requires that at least the contact zone to be touched completes the electrical circuit and is relatively corrosion resistant. Therefore, a surface film with high electrical resistance is not formed during use. in general The contacts also need to be resistant to mechanical wear.

Corrosion resistance on the one hand and mechanical wear resistance required for the contact zone to endure on the other hand Resistance depends on the atmosphere in which the contact operates, contact pressure, switching frequency, and the nature of the contact operation, i.e. Contacts rely on functions such as making sliding or mating contacts.

Atmospheres containing trace amounts of hydrogen sulfide, chlorine, sulfur dioxide, and It will cause corrosion.

On the other hand, high contact pressure causes contact and damage through the resulting surface film, and the corrosion resistance of these Not effective in the environment. The effect is if a sliding contact is used instead of a bonding contact. It grows when it gets wet. This is because the action of sliding between two surfaces cleanses them. This is because that. On the other hand, as high contact pressure failures represent frequent operation, This means that there is a tendency to increase surface wear.

Other factors that influence the design of contacts are the voltage at which they open and close and the current at which they are supplied and interrupted. It is. The present invention relates generally to lightweight contacts, and more particularly to computer contacts. For use with lightweight, highly reliable ``dedicated'' connectors of the type used in However, the invention is not limited thereto.

Typically such contacts carry less than 1 ampere of current and do not corrode under these conditions. The effects of food are truly remarkable. Therefore, it is possible to use a corrosion-resistant type of lightweight contact that is economically practical. It is important to make tentacles. At the same time, such contacts are used for a long time, sometimes 30 years. There are seven types that are required to withstand constant use. Therefore, it is as wear resistant as possible. It is also important that it is made in such a way.

For contacts that require severe corrosion resistance and mechanical wear, end pieces for printed circuit boards are used. It is used separately for connectors, push buttons, and keyboard switches.

The contact zone of a contactor of the above type, especially a contact element used in a device of the above type, is Until now, a 5 micron thick layer of gold alloy, such as 98% gold/cobalt alloy, has been applied to I was eating.

Rising gold prices have led to reductions in the thickness of gold alloy layers, some as thick as 2.5 microns. layers were used.

However, such a reduction in thickness results in a Hiko contact that is sensitive to wear. Fruit use life is reduced.

This can also be done at an acceptable cost without reducing its life under acceptable limits. Methods have been devised to improve the wear resistance of children.

West German patent specification 1089491 is used as a contact material for low current electrical contacts Provides alloys containing 5-65% radium, 15-55% silver and 15-70% gold do. These alloys are susceptible to surface corrosion in sulfur-containing atmospheres and It is extremely resistant to exposure to the chemicals present in the equipment used - thereby exhibiting poor corrosion resistance It is said that there is resistance.

Other successful methods include a 25-inch thick unswirled thin gold alloy inlet (0.000), The gold alloy coating was replaced by B. Inlays are not necessarily electroplated. cover is not applicable, especially if the contacts are small and electroplating is done after contact formation. The first advantage is that it is limited to where it is needed even if The second advantage is that it can be used in a relatively wide range of applications. relatively few Such an alloy is a conductive metal or alloy on the contact element or from which the contact element is formed. is effectively electroplated onto a sheet or layer of.

The alloy used for the inlay contains a 75Au/25Ag alloy. But Hiko? However, this alloy is still expensive in view of its relatively high gold content. Furthermore, for example, phosphorus Inlays of such alloys within base metals, such as those made from bronze and other copper-containing alloys, are This leads to an effect known as ``edge creep,'' which is the formation of a thin layer of corrosion products. or the membrane is removed from the interface between the inlay material and the material of the inlaid object by expensive metals. It is a corrosive effect that creeps on the surface of the inlay. This is a self-stabilizing process. It seems that the film formed by the corrosion products in the process borders the passage of other corrosion products. This slows down the formation of the film until its formation actually stops.

Despite this, the film often grows to a width of 2 or more, so that the growth interfere with the element. In the element the contact zone is small and for example in a phosphor bronze matrix. It has expensive metal inlays. In fact, edge creep is the most common type of contact failure. This is one of many causes.

Edge creep, i.e. the inlay and base metal or alloy are placed closer together The resulting corrosion at the interface is a more normal atmosphere that affects the contact resistance of the contact surfaces. Not related to ambient corrosion. Metals or alloys that exhibit good corrosion resistance are used as inlays. It is often unsuitable for use because it is prone to edge creep. The main thing in this example is pure gold with excellent corrosion resistance.

One object of the invention is that contact elements including inlaid contact zones are fabricated. By providing an inlaid object with a Elements with a relatively high gold content in the contact zone (such as 75Au/25Ag) It has a contact zone that is less susceptible to Tsuji creep effects and, like known contact elements, Inlaid alloys that are at least resistant to mechanical wear and surface corrosion It is cheaper than known contact elements with.

Surprisingly, these conditions hold true for V silver/platinum metal (pgm) composites as inlays. This is achieved by using gold, and in the alloy, platinum group metals, platinum, One or more of radium, ronium, iridium, osmium, ruthenium may be higher, preferably palladium.

According to one feature of the invention, the contact zone (as defined) is an inlay or an inlay. manufacture an electrical contact element (as defined) constituted by a portion of an inlay; A base metal or base metal alloy body formed into an inlay, wherein the inlay is free of impurities. Contains one or more of gold, silver and copper, nickel and indium in addition to containing one or more platinum group metals and no other platinum group metals An inlaid base metal or base metal alloy formed from one or more alloys. It is to provide the gold body.

Preferably: (b) The inlay has a weight engagement of 25-4.0%, 30-40% silver, and other impurities. (b) in which case the remainder is made of one or more alloys consisting of palladium; The gold body is made of phosphor bronze, copper-nickel, copper-chromium or copper-beryllium alloy. (c) In the base metal or alloy body having a recessed surface covered with a nickel layer. An alloy body of an appropriate shape is diffusion bonded into a pre-made recess, and then a reduction of about 60% is achieved. The inlaid alloy body is formed by rolling the composite at a surface area. .

According to another feature of the invention we provide one or more suitably shaped inlay alloys. The body is diffusion bonded into a pre-formed recess in the base alloy body and the composite is then cold-pressured. The inlaid base metal or base metal alloy, which is one of the features of the present invention, extends A method of manufacturing a metal body is provided.

Additionally, the surface of the recess may be coated before inserting the inlay object.

The invention also comprises inlaying one or more objects of the type hitherto described. Contains electrical contact elements made.

(a) Corrosion, (b) Edge creep effect and e) Mechanical wear. Various tests conducted to determine the resistance of such inlaid parts are described. .

75 used to form inlaid contact zones of prior art electrical contact elements. The test chamber was made of the same material in which the inlay part was formed from Au/25Ag alloy. It was implemented. As will be appreciated, the results of the various tests do not demonstrate the effectiveness of our invention. Show clearly.

For each test, one or more inlaid phosphor bronze objects are ready. and an accelerated environment of 2-6 weeks in 2-week steps. each tess Upon completion of one or more of the two-week steps of the test or each test, the The contact resistance of each inlay was measured under conditions where the degree of corrosion on the inlay surface was controlled. obtained by doing. Finally, the metal used for the inlay of the selected object The abrasion resistance of the gold was evaluated using the method described below.

Details of the test method are as follows. The alloy from which the inlay is made is induction melted. The material was then cold-rolled to produce a fine-grained homogeneous material for the number of tests. of each alloy sample The surface was well polished to give a maximum initial value of contact resistance of less than 5 mΩ. inlay Next, hot-bond the test alloy to the phosphor bronze (IJ) tube with grooves in advance, and It was produced by cold rolling the composite to an area reduction of about 60%.

The accelerated corrosion test was then carried out at 100ppbS02.20ppbct2 and 1.5 Atmosphere containing 0 ppbN02 or 100 ppbH2S, 100 p The inlet was placed in an atmosphere containing pbsO2, 20ppbCt2 and 150ppbNO2. The experiment was carried out by exposing the transformed material. As understood, if the second atmosphere is 100pp The first atmosphere involves the addition of bH2S, and the second atmosphere was found to be severe in corrosion tests. different levels. Exposure was carried out at a temperature and humidity of 30±1℃ and 75±3φ. Each done and inlaid item is exposed to one or more of two weeks for a maximum of six weeks. exposed.

This is true for silver samples placed in these atmospheres and for samples exposed to outdoor air. A comparison of the depths of corrosion films created by these atmospheres shows that corrosion in these atmospheres is The eclipse rate is shown to be at least 100 times the outdoor rate. Therefore゛ The 'acceleration' function is approximately 100.

After exposing the inlayed objects in the test chamber, the contact resistance of each inlay will be automatically along the inlay by a computer that controls a contact resistance device that calculates and indicates the resistance value. was determined using 100 equidistant points. In order to carry out this measurement, the polished diameter 1 ．． 5 Place the hemispherical gold globe of tran on each inlay using ioO,y force. A voltage of L2 and a current of 10 mA are continuously passed in that direction between the Zorop and the inlay. is. Contact resistance was determined from the voltage drop between the probe and the inlay.

Two alloys used to form the inlay of the article according to the invention and a conventional 75A used to form an inlaid contact zone of a technical contact element, The abrasion resistance of u/25A,g is the alloy disc while rubbing a flat sheet of the same material. By measuring the size of the wear marks created by rotating the Predetermined.

The results of the contact resistance test and the range of ZOCRISO are shown in Tables 1 and 2, On the other hand, changes in edge creep range with time for various inlays are shown in Figures 1 and 2. Shown in Figure 2.

It was difficult to compare the contact resistance between the two readings, and there was some variation. death However, samples that give a low contact resistance are considered to have effective corrosion resistance. It is clear that the open circuit (O/C) reading indicates a highly corroded sample. It is. All contact resistance data presented in the table are 50% values, thereby At least 50 of the 100 contact resistances taken in each case fall below the quoted value. Chiru.

As understood, the test conditions are open circuit readings of two prior art 75A u/25 　A　G inlay and sufficiently severe to give 500 mΩ contact resistance to others. However, many of the Au/Ag and /pd alloys had low contact resistance.

Alloys containing 375% Au and 32% Au gave particularly good results.

The edge creep results in the attached drawings are similar to most of the Au/Ag/Pd alloys tested. , edge creep superior to that of the conventional 75Au/25Ag alloy inlay. Au/Ag with a small amount of copper, indium or nickel to increase creep resistance /Pd edge creep.

Finally, 37% by weight AAu/ which shows the alloy used for the inlay according to the present invention 33% by weight Ag, 30% by weight Pd, 32% by weight Au / 34% by weight Pd and Wear resistance tests conducted on sample alloys containing 75 wt% Au/25 wt% Ag. The steel is more wear resistant than prior art 75 Au/Ag alloys. 37 weight φ and 3 The surface area of the wear marks formed on the alloy containing 2 weights of Au is respectively],, 2 mm It was 2 and 15 screams 2. On the other hand, a table of wear marks formed on 75Au/25A and g alloys. The area was 2.2 mn2.

All cap wear tests were performed on 60% cold worked alloy and the results obtained were as follows: considered to provide a practical evaluation of the use of contact elements containing inlays of these alloys. It will be done.

Electrical contact elements and the like suitable for use in edge connectors include: For example, if necessary, intermediate annealing is performed and the resulting sheet is rolled to a predetermined thickness. The elements or the blanks from which the contact elements are made in one or more operations are It may also be made from inlays of the type used in previous tests by stomach.

The invention is limited to those with corrosion-resistant inlays in which contact elements of the above type are made. It will be understood that there is no. In fact, in the product according to the present invention, the corrosion resistance of the inlay is a desired property. It may also be used to form products other than contact elements for certain applications. Also various things It can also be used in various applications.

Engraving (no changes to the content) Test partner Nao Tsuki (sho) △ 5B, 5 Au/2L+, 5 Ag/17Pdv 37.5 Au/29. 5Ag/30Pd/3Cw Order 37 Au/2L+g/3O-Pd・32 At4/34Ag/34Pd procedural amendment (method) %formula% 1 Display of incident PCT/GB82100349 2 Name of the invention Light corrosion resistant contact 3 Person making the amendment Relationship to the incident: Patent applicant Name Johnson Matthey Public Limited Company 〼 Gose・ 5 Date of amendment order → 6 Target of correction (1) Document pursuant to the provisions of Article 184-5, Paragraph 1 of the Patent Act (2) Translation/text of drawings (3) Power of attorney 7 Contents of amendment (1) (3) Attached sheet (2) As attached (no change in content) 8 List of attached documents (1)! One document pursuant to the provisions of Article 184-5, Paragraph 1 of the Vf Permit Act (2) One translation of the drawing (3) Power of attorney and its translation: one copy each of the international search report

Claims (1)

[Claims] 1. Electrical contact element whose contact zone is constituted by an inlay or a part of an inlay An inlaid base metal or base metal alloy body for producing an inlaid base metal or base metal alloy body, B contains one or more of gold, silver and copper, nickel and indium apart from impurities. One or more platinum group metals with trace amounts of platinum group metals and no other platinum group metals an inlaid base metal formed from one or more alloys consisting of or Base metal alloy body. 2 Impurities in which the inlay is palladium and a small amount of Rh and/or Ir In addition, 1 containing 32-58.5% by weight of Au, 3% by weight of Cu, Ni or In 〇-58 wt% Ag and one or more alloys containing wt% Ag 3. The alloy body according to claim 1 or 2, wherein the alloy body is formed from an alloy of more than or equal to the above. 4. Claims 1 to 3, wherein the remainder is parazoum apart from impurities. The alloy body described in any of the preceding paragraphs. 5 Claims 1 to 4 in which the inlay alloy contains 3% by weight CLL The alloy body described in any of the above. 6. The inlay alloy contains 3% by weight In and is described in the range of requirements from item 1 to item 5. alloy body. 7. Claims 1 to 6 in which the inlay alloy contains 3% by weight Ni The alloy body described in any of the above. 8. The base metal or base metal alloy body is phosphor bronze, copper-2, kel, copper-chromium, or copper. - a nickel layer sandwiched between the beryllium alloy and the recessed surface and associated inlay; An alloy body according to any one of claims 1 to 7 formed from. 9. A claim in which the inlay is diffusion bonded within a groove in the base metal or alloy. The alloy body according to any one of items 1 to 8. 10 Claims in which the components of the inlay alloy are listed in Table 1 or Table 2 The alloy body according to item 1 below. 1], one or more inlays according to any one of the claims up to item 10. An electrical contact element made from a metal alloy. 12. Adding one or more suitably shaped inlay alloy bodies to the base metal or alloy body Items 1 to 8, wherein the composite is joined into a preformed recess and then cold rolled. Producing the inlayed base metal or base metal alloy body described in any one of the preceding paragraphs. How to build. 13.Claim 12, wherein the cold rolling is carried out to achieve an area reduction rate of 60%. How to put it on. 14. Claim 18: The surface of the recess is coated with nickel. The method according to item 12 or 13.