EP0437917A2 - Internal-oxidation method for production of electrical contact materials - Google Patents
Internal-oxidation method for production of electrical contact materials Download PDFInfo
- Publication number
- EP0437917A2 EP0437917A2 EP90308996A EP90308996A EP0437917A2 EP 0437917 A2 EP0437917 A2 EP 0437917A2 EP 90308996 A EP90308996 A EP 90308996A EP 90308996 A EP90308996 A EP 90308996A EP 0437917 A2 EP0437917 A2 EP 0437917A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- internal
- weight
- electrical contact
- silver
- alloys
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H1/00—Contacts
- H01H1/02—Contacts characterised by the material thereof
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C32/00—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ
- C22C32/001—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ with only oxides
- C22C32/0015—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ with only oxides with only single oxides as main non-metallic constituents
- C22C32/0021—Matrix based on noble metals, Cu or alloys thereof
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H1/00—Contacts
- H01H1/02—Contacts characterised by the material thereof
- H01H1/021—Composite material
- H01H1/023—Composite material having a noble metal as the basic material
- H01H1/0237—Composite material having a noble metal as the basic material and containing oxides
- H01H1/02372—Composite material having a noble metal as the basic material and containing oxides containing as major components one or more oxides of the following elements only: Cd, Sn, Zn, In, Bi, Sb or Te
- H01H1/02376—Composite material having a noble metal as the basic material and containing oxides containing as major components one or more oxides of the following elements only: Cd, Sn, Zn, In, Bi, Sb or Te containing as major component SnO2
Definitions
- This invention relates to a method for making electrical contact materials by the internal-oxidation of silver-solute metals alloys, whereby the solute metals in the silver matrix are converted to metal oxides which afford the alloys a high refractoriness. And, this invention also relates to such electrical contact materials, matrices of which are silver and which are produced in accordance with this invention method.
- Silver-tin oxides alloys matrices of which are silver and solute elements of which are tin which are in turn internal-oxidized to tin oxides, are widely employed today as electrical contact materials.
- silver-cadmium oxides alloys are known as efficient electrical contact materials, though compared to the silver-tin oxides alloys, they are less employed, because cadmium is harmful to health and becuase of the prevention of pollution.
- auxiliary solute metals which have faster diffusion velocities and according are capable to carry and convey oxygen towards the inside of silver matrices fast.
- a typical example of such auxiliary solute metals is indium.
- silver-tin-indium system alloys are internal-oxidized to abtain excellent electrical contact materials.
- electrical contact materials which are one of the best electrical contact materials industrially used today, are made by internal-oxidizing silver alloys containing 5-10 weight % of tin and 1.0-6 weight % of indium.
- the present inventor has sought for a method of the internal-oxidation of silver-tin alloys completely and evenly without employing any auxiliary solute metal element such as indium or at least with the employment of a minimum trace amount of the auxiliary solute metal element. He perceived Zr.
- Zr has very small solid-solubility with silver. Accordingly, when molten alloys of Ag-Sn-Zr are cooled to a solid phase, almost entire amounts of Zr contained in the alloys are precipitated dispersedly and evenly in the solid phase of Ag-Sn alloy structures. At a temperature between 500-700°C for the internal-oxidation, Zr atoms thus dispersedly precipitated remain in silver matrices as they were precipitated or as inter-metallic compounds produced with Sn at sites where they were precipitated, and act as nuclei for the oxidation and precipitation of Sn.
- Zr is employed at an amount as much as small or at a nominal amount.
- the employment of Zr is advantageous also in respect of the fact that their oxides are not so weak, and zirconium oxides have a higher refractoriness than tin oxides.
- the present inventor has conducted a large number of various experiments, and discovered that even with Zr of such trace amount as 0.05-0.1 weight %, Ag-Sn alloys which contain Sn of more than 4.5% to 12%, an amount near to the upper limit of solid-solubility of Sn to Ag, can be internal-oxidized completely, if an oxygen atmosphere for the internal-oxidation is made remarkably high such as more than 10 atm.
- a method of the complete internal-oxidation of Ag alloys which is consisted of Sn of more than 4.5 weight % to 12 weight % and a balance of Ag, is provided in which Zr is added to the alloys at a trace amount of 0.05 weight % to 0.1 weight %, and the alloys are internal-oxidized at an oxygen atmosphere of more than 10 atm.
- This invention is also to provide electrical contact materials obtained by this method.
- the above constituent (1) was melted and made to an ingot of 120mm in diameter and 40mm in length.
- the ingot was hot-extruded into squre bars of 30mm in thickness and 50mm in width.
- the bars were then cut to a length of 500mm each, and their upper and lower surfaces were shaved by a thickness of 3mm each to obtain square bars of 24mm in thickness, 510mm in width, and 500mm in length.
- Alloys of the above constituents (2) and (3) of this invention were made, similarly to the above (1), into disk-shaped contacts backed with pure silver, of 6mm in diameter and 1.2mm in thickness. They were internal-oxidized, similarly to the above (1), however that in this instance, the oxygen atmosphere was made to 30 atm.
- this conventional alloy (4) was prepared. Though this contains harmful Cd, it is known as it has fine and uniform internal oxidized structures, and in fact, it is one of the excellent today's electrical contact materials having good electrical properties.
- This alloy (4) was internal-oxidized similarly to the alloys (1), that is, in a normal oxygen atmosphere.
- Amounts of consumption (mg) by ASTM test method were as follows.
- this invention can provide electrical contact materials which are made by the internal-oxidation of Ag-Sn system alloys, provided with excellent electrical performance as electrical contacts on account of extremely fine metal oxides evenly and uniformally dispered in Ag matrices.
- one or more elements of iron family elements may be added to alloys, solely for account of further fining alloy structures. But, this is neither intended for the acceleration nor assistance of internal-oxidation by such elements.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Composite Materials (AREA)
- Contacts (AREA)
- Manufacture Of Alloys Or Alloy Compounds (AREA)
- Manufacture Of Switches (AREA)
Abstract
Description
- This invention relates to a method for making electrical contact materials by the internal-oxidation of silver-solute metals alloys, whereby the solute metals in the silver matrix are converted to metal oxides which afford the alloys a high refractoriness. And, this invention also relates to such electrical contact materials, matrices of which are silver and which are produced in accordance with this invention method.
- Silver-tin oxides alloys, matrices of which are silver and solute elements of which are tin which are in turn internal-oxidized to tin oxides, are widely employed today as electrical contact materials.
- Similarly, silver-cadmium oxides alloys are known as efficient electrical contact materials, though compared to the silver-tin oxides alloys, they are less employed, because cadmium is harmful to health and becuase of the prevention of pollution.
- However, there is a problem for preparing silver-tin oxides alloys by means of internal-oxidation. That is, when a silver matrix of an alloy contains more than about 4.5 weight % of tin, the entire amount of such tin can hardly be internal-oxidized by oxygen which penetrates from the outside of the silver matrix and into the matrix.
- In order to solve this problem, it becomes necessary to add to silver-tin alloys such auxiliary solute metals which have faster diffusion velocities and according are capable to carry and convey oxygen towards the inside of silver matrices fast. A typical example of such auxiliary solute metals is indium. In U.S. Patent No. 3,933,485, there is described that silver-tin-indium system alloys are internal-oxidized to abtain excellent electrical contact materials. In this U.S. Patent, electrical contact materials which are one of the best electrical contact materials industrially used today, are made by internal-oxidizing silver alloys containing 5-10 weight % of tin and 1.0-6 weight % of indium.
- However, even when indium which acts well as the above-mentioned auxiliary solute metal, is added, it is not easy to internal-oxidize tin of more than 4.5% most evenly in a silver matrix. Sometimes, tin oxides tend to segregate excessively about surface areas of the silver matrix, while they are depleted at inner areas. In addition to such drawback, indium oxides are comparatively weak.
- Hence, it is desireable to internal-oxidize tin in a silver matrices without employing indium, if possible.
- In view of the above-mentioned background, the present inventor has sought for a method of the internal-oxidation of silver-tin alloys completely and evenly without employing any auxiliary solute metal element such as indium or at least with the employment of a minimum trace amount of the auxiliary solute metal element. He perceived Zr.
- Zr has very small solid-solubility with silver. Accordingly, when molten alloys of Ag-Sn-Zr are cooled to a solid phase, almost entire amounts of Zr contained in the alloys are precipitated dispersedly and evenly in the solid phase of Ag-Sn alloy structures. At a temperature between 500-700°C for the internal-oxidation, Zr atoms thus dispersedly precipitated remain in silver matrices as they were precipitated or as inter-metallic compounds produced with Sn at sites where they were precipitated, and act as nuclei for the oxidation and precipitation of Sn. Therefore, in this invention, as an auxiliary solute metal element which assists the internal-oxidation of Sn in Ag matrices, Zr is employed at an amount as much as small or at a nominal amount. The employment of Zr is advantageous also in respect of the fact that their oxides are not so weak, and zirconium oxides have a higher refractoriness than tin oxides.
- In connection with the employment of Zr for the internal-oxidation of Ag-Sn system alloys, it shall be noted that an example of the internal-oxidation of Ag-Sn 6%-Zr 0.5% are given in Japanese Preliminary Patent Publication No. 51-121795. In spite of such example, it has been found by the present inventor that when Zr is employed at a trace amount such as 0.05-0.1 weight % as employed in this invention, it is impossible to internal-oxidize Sn of an amount of more than 4.5% completely and evenly all over the silver matrices as Sn oxides which are precipitated uniformally as fine particles.
- Therefore, the present inventor has conducted a large number of various experiments, and discovered that even with Zr of such trace amount as 0.05-0.1 weight %, Ag-Sn alloys which contain Sn of more than 4.5% to 12%, an amount near to the upper limit of solid-solubility of Sn to Ag, can be internal-oxidized completely, if an oxygen atmosphere for the internal-oxidation is made remarkably high such as more than 10 atm.
- That is, in this invention, a method of the complete internal-oxidation of Ag alloys which is consisted of Sn of more than 4.5 weight % to 12 weight % and a balance of Ag, is provided in which Zr is added to the alloys at a trace amount of 0.05 weight % to 0.1 weight %, and the alloys are internal-oxidized at an oxygen atmosphere of more than 10 atm. This invention is also to provide electrical contact materials obtained by this method.
- As described above, while in the method of this invention, the successful and complete internal-oxidation of Ag-Sn alloys of the above-mentioned specific constituents can be made, if the internal-oxidation is conducted with an oxygen atmosphere of more than 10 atm, it is not desireable in respect of costs and safety to employ a very extremely high oxygen atmosphere at an industrial scale. In this view and in order to prevent Ag from becoming liquid (at about 400 atm) in the course of internal-oxidation, 200 atm of oxygen which can commercially be obtained, is selected as a maximum atmospheric pressure employable in this invention.
- This invention is explained in a further concrete manner in the following examples.
- In order to confirm the present inventor's above-mentioned findings that Ag alloys containing Sn of 4.5 weight % and over, can not successfully be internal-oxidized by the mere addition of Zr of a trace amount, the above constituent (1) was melted and made to an ingot of 120mm in diameter and 40mm in length. The ingot was hot-extruded into squre bars of 30mm in thickness and 50mm in width. The bars were then cut to a length of 500mm each, and their upper and lower surfaces were shaved by a thickness of 3mm each to obtain square bars of 24mm in thickness, 510mm in width, and 500mm in length.
- To each lower surface of the square bars, there were bounded pure silver of 2.5mm in thickness. They were rolled by pressure so that they had thickness of 1.2mm. By punching them by a punch having a cutting hole of 6mm in diameter, disk-shaped contact materials backed by the pure silver and having 6mm diameter and 1.2mm thickness were obtained.
- They were internal-oxidized by heating them to 620°C for 24 hours in an oxygen atmosphere of 7 atm.
- Vertically cut-out sections of the contacts (1) thus obtained were observed by a microscope. It was observed that subscales made from segregations of metal oxides about surfaces prevented oxygen to penetrate inwardly and, consequently prevented the oxidation of the alloys at inner deeper areas.
- Alloys of the above constituents (2) and (3) of this invention were made, similarly to the above (1), into disk-shaped contacts backed with pure silver, of 6mm in diameter and 1.2mm in thickness. They were internal-oxidized, similarly to the above (1), however that in this instance, the oxygen atmosphere was made to 30 atm.
- Microscopic observation of the contacts thus internal-oxidized, along their vertically cut sections showed that they had structures evenly dispersed with metal oxides over and through their entire areas, similarly to the undermentioned (4) contacts, and that internal oxidation was completely made.
- For the sake of comparison, this conventional alloy (4) was prepared. Though this contains harmful Cd, it is known as it has fine and uniform internal oxidized structures, and in fact, it is one of the excellent today's electrical contact materials having good electrical properties.
- This alloy (4) was internal-oxidized similarly to the alloys (1), that is, in a normal oxygen atmosphere.
-
-
-
- As readily known from the above, this invention can provide electrical contact materials which are made by the internal-oxidation of Ag-Sn system alloys, provided with excellent electrical performance as electrical contacts on account of extremely fine metal oxides evenly and uniformally dispered in Ag matrices.
- In this invention, as seen in the above example of alloy (3), one or more elements of iron family elements (Ni, Co, and Fe) may be added to alloys, solely for account of further fining alloy structures. But, this is neither intended for the acceleration nor assistance of internal-oxidation by such elements.
Claims (3)
- A method of internal oxidation of a silver alloy to obtain an electrical contact material, in which method the alloy consists of from more than 4.5 weight % to 12 weight % Sn, from 0.05 to 0.1 weight % of Zr, and the balance Ag; and the alloy is internally oxidised in an oxygen atmosphere of from more than 10 to 200 atm.
- method as claimed in claim 1, in which the alloy also contain one or more of the elements Ni, Co and Fe, in an amount of 0.001-1 weight %.
- An electrical contact material made of an internally oxidized alloy obtained by a process as claimed in claim 1 or claim 2.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP9909/90 | 1990-01-19 | ||
JP2009909A JPH03215635A (en) | 1990-01-19 | 1990-01-19 | Internal oxidation of electrical contact material and electrical contact material |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0437917A2 true EP0437917A2 (en) | 1991-07-24 |
EP0437917A3 EP0437917A3 (en) | 1992-04-22 |
EP0437917B1 EP0437917B1 (en) | 1994-10-19 |
Family
ID=11733239
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP90308996A Expired - Lifetime EP0437917B1 (en) | 1990-01-19 | 1990-08-16 | Internal-oxidation method for production of electrical contact materials |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP0437917B1 (en) |
JP (1) | JPH03215635A (en) |
KR (1) | KR910014967A (en) |
CN (1) | CN1053509A (en) |
DE (1) | DE69013485T2 (en) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN103714981B (en) * | 2013-12-20 | 2015-08-05 | 宁波赛特勒电子有限公司 | A kind of relay |
CN108220650A (en) * | 2017-12-27 | 2018-06-29 | 昆明贵金属研究所 | A kind of multicomponent oxide enhancing silver-based electric contact material and preparation method thereof |
CN110983096A (en) * | 2019-12-07 | 2020-04-10 | 福达合金材料股份有限公司 | Method for preparing silver matrix oxide electric contact material by internal oxidation method capable of improving fusion welding resistance |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB611813A (en) * | 1945-07-28 | 1948-11-04 | Mallory Metallurg Prod Ltd | Improvements in and relating to the production of metal-metal oxide compositions or alloys |
FR2084338A5 (en) * | 1970-03-09 | 1971-12-17 | Duerrwaechter E Dr Doduco | |
US3933485A (en) * | 1973-07-20 | 1976-01-20 | Chugai Denki Kogyo Kabushiki-Kaisha | Electrical contact material |
JPS51121795A (en) * | 1975-04-17 | 1976-10-25 | Nippon Tungsten Co Ltd | Ag-tin oxide-system electric contact material |
US4472211A (en) * | 1982-05-20 | 1984-09-18 | Chugai Denki Kogyo Kobushiki Kaisha | Method of internally oxidizing Ag-Sn alloy contact material |
-
1990
- 1990-01-19 JP JP2009909A patent/JPH03215635A/en active Pending
- 1990-08-16 EP EP90308996A patent/EP0437917B1/en not_active Expired - Lifetime
- 1990-08-16 KR KR1019900012768A patent/KR910014967A/en not_active Application Discontinuation
- 1990-08-16 DE DE69013485T patent/DE69013485T2/en not_active Expired - Fee Related
- 1990-09-10 CN CN90107574A patent/CN1053509A/en active Pending
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB611813A (en) * | 1945-07-28 | 1948-11-04 | Mallory Metallurg Prod Ltd | Improvements in and relating to the production of metal-metal oxide compositions or alloys |
FR2084338A5 (en) * | 1970-03-09 | 1971-12-17 | Duerrwaechter E Dr Doduco | |
US3933485A (en) * | 1973-07-20 | 1976-01-20 | Chugai Denki Kogyo Kabushiki-Kaisha | Electrical contact material |
JPS51121795A (en) * | 1975-04-17 | 1976-10-25 | Nippon Tungsten Co Ltd | Ag-tin oxide-system electric contact material |
US4472211A (en) * | 1982-05-20 | 1984-09-18 | Chugai Denki Kogyo Kobushiki Kaisha | Method of internally oxidizing Ag-Sn alloy contact material |
Non-Patent Citations (3)
Title |
---|
& JP-A-51 121 795 (NIPPON TUNGSTEN K. K.) 26 October 1976 * |
WORLD PATENTS INDEX Week 7650, Derwent Publications Ltd., London, GB; AN 76-93023X (50) * |
Z. METALLKUNDE vol. 64, no. 4, 1973, pages 286 - 295; & GRABKE, H. J.: 'Die innere Oxidation von Silberlegierungen bei hohen Dr}cken und in atomarem Sauerstoff' * |
Also Published As
Publication number | Publication date |
---|---|
JPH03215635A (en) | 1991-09-20 |
DE69013485T2 (en) | 1995-05-04 |
DE69013485D1 (en) | 1994-11-24 |
KR910014967A (en) | 1991-08-31 |
EP0437917B1 (en) | 1994-10-19 |
CN1053509A (en) | 1991-07-31 |
EP0437917A3 (en) | 1992-04-22 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US4150982A (en) | AG-Metal oxides electrical contact materials containing internally oxidized indium oxides and/or tin oxides | |
EP0031159B1 (en) | Electrical contact | |
CA1133285A (en) | Electrical contact materials of internally oxidized ag-sn-bi alloy | |
KR0170798B1 (en) | Electric contact point material | |
US4680162A (en) | Method for preparing Ag-SnO system alloy electrical contact material | |
EP0437917B1 (en) | Internal-oxidation method for production of electrical contact materials | |
EP0508746A1 (en) | Internally oxidised Ag-Sn-In alloy electrical contact materials and manufacturing method thereof | |
US5078810A (en) | Method of making Ag-SnO contact materials by high pressure internal oxidation | |
EP0172411A1 (en) | Vacuum contactor with contact pieces of CuCr and process for the production of such contact pieces | |
US4981533A (en) | Internal-oxidation method of electrical contact materials and the materials produced thereby | |
US4636270A (en) | Internal oxidized Ag-Sn system alloy contact materials | |
Stevens | Powder-metallurgy solutions to electrical-contact problems | |
EP0460680B1 (en) | Contact for a vacuum interrupter | |
US3437479A (en) | Contact materials for vacuum switches | |
GB2055398A (en) | Electrical contact materials of internally oxidized Ag-Sn-Bi alloy | |
US4695330A (en) | Method of manufacturing internal oxidized Ag-SnO system alloy contact materials | |
US5147728A (en) | Ag-SnO2 electrical contact materials | |
US4647322A (en) | Internal oxidized Ag-SnO system alloy electrical contact materials | |
US5102480A (en) | Ag-sno-cdo electrical contact materials and manufacturing method thereof | |
EP0441018A1 (en) | Ag-Sn0 electrical contact materials and manufacturing method thereof | |
GB2093066A (en) | Electrical contact material | |
JP3751327B2 (en) | Silver-oxide based electrical contact element | |
US2161576A (en) | Silver base alloy | |
CA2009671A1 (en) | Ag-sno electrical contact materials and manufacturing method thereof | |
JP4455871B2 (en) | Electrical relay contact material and electrical relay contact |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
AK | Designated contracting states |
Kind code of ref document: A2 Designated state(s): DE FR GB |
|
17P | Request for examination filed |
Effective date: 19911111 |
|
PUAL | Search report despatched |
Free format text: ORIGINAL CODE: 0009013 |
|
AK | Designated contracting states |
Kind code of ref document: A3 Designated state(s): DE FR GB |
|
17Q | First examination report despatched |
Effective date: 19931206 |
|
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): DE FR GB |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: FR Effective date: 19941019 |
|
REF | Corresponds to: |
Ref document number: 69013485 Country of ref document: DE Date of ref document: 19941124 |
|
EN | Fr: translation not filed | ||
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: GB Effective date: 19950816 |
|
PLBE | No opposition filed within time limit |
Free format text: ORIGINAL CODE: 0009261 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT |
|
26N | No opposition filed | ||
GBPC | Gb: european patent ceased through non-payment of renewal fee |
Effective date: 19950816 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: DE Payment date: 19970822 Year of fee payment: 8 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: DE Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 19990601 |