# US 9,437,342 B2 · Method for preparing silver-based electrical contact material

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- Number: US 9,437,342 B2
- Document ID: US9437342B2
- Status: Granted
- Kind: B2
- Application number: 14/389,444
- Filed: 2013-03-29
- Published: 2015-03-26
- Granted: 2016-09-06
- Earliest claimed: 2012-03-30
- Assignees: Schneider Electric Industries SAS
- Applicants: Schneider Electric Industries SAS
- Inventors: Nan Liu; Binyuan Zhao; Yijian Lai
- Web page: https://patentgrep.com/patent/US9437342B2

## CPC

- H01B 1/04: mainly consisting of carbon-silicon compounds, carbon or silicon
- B22F 1/16: Metallic particles coated with a non-metal (coated with lubricating or binding agents or with organic material B22F1/10)
- B22F 9/24: starting from liquid metal compounds, e.g. solutions
- C01B 32/26: Preparation (by using ultra-high pressure B01J3/06; by crystal growth C30B29/04)
- C22C 5/06: Alloys based on silver
- C22F 1/14: of noble metals or alloys based thereon
- H01B 1/02: mainly consisting of metals or alloys
- H01H 1/023: having a noble metal as the basic material
- H01H 1/027: containing carbon particles or fibres
- H01H 11/04: of switch contacts
- B22F 2304/056: Particle size above 100 nm up to 300 nm
- B22F 2304/058: Particle size above 300 nm up to 1 micrometer
- B22F 2304/10: Micron size particles, i.e. above 1 micrometer up to 500 micrometer
- B22F 2998/10: Processes characterised by the sequence of their steps
- H01H 11/048: {by powder-metallurgical processes}
- H01H 2300/036: Application nanoparticles, e.g. nanotubes, integrated in switch components, e.g. contacts, the switch itself being clearly of a different scale, e.g. greater than nanoscale
- H01B: CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES (selection for magnetic properties H01F1/00; waveguides H01P {; printed circuits H05K})
- B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- C22F: CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass, C23F17/00)
- H01H: ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES (contact cables H01B7/10; electrolytic self-interrupters H01G9/18; emergency protective circuit arrangements H02H; switching by electronic means without contact-making H03K17/00)

## Abstract

The present invention relates to a new method for preparing a silver-based electrical contact material, comprising following steps of: (a) providing a carbonaceous mesophase solution; (b) adding a silver source into the carbonaceous mesophase solution and stirring to obtain a compound; (c) removing a solvent from the compound to obtain a solid; (d) performing a heat treatment on the solid, and obtaining a silver-based electrical contact material. The silver source is silver powder prepared by means of a chemical method. By means of the method, a uniform carbonaceous coating on silver is implemented, the silver is uniformly distributed in a nanometer scale, and a diamond is generated in situ of a material after being sintered. The silver-based electrical contact material processed by means of this method shows an excellent mechanical wear resistance and electrical property.

## Claims

### Claim 1

A method for preparing a silver-based electrical contact material, comprising the following steps:
(a) providing a carbonaceous mesophase solution;
(b) adding a silver source to the carbonaceous mesophase solution under stirring to obtain a mixture;
(c) removing a solvent from the mixture to obtain a solid; and
(d) subjecting the solid to a heat treatment to obtain a silver-based electrical contact material,
wherein the silver source is silver powder prepared by a chemical method; and wherein carbon in the form of diamond is generated in the electrical contact material.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the silver powder has a particle size in the range of from 100 nm to 100 μm.

### Claim 3 (depends on 1)

The method according to claim 1, wherein the carbonaceous mesophase comprises biomass-derived carbonaceous mesophase.

### Claim 4 (depends on 1)

The method according to claim 1, wherein the concentration of the carbonaceous mesophase solution is 0.005 to 6% by weight.

### Claim 5 (depends on 1)

The method according to claim 1, comprising a step of adding a catalyst to the carbonaceous mesophase solution during step (a), step (b) or both.

### Claim 6 (depends on 5)

The method according to claim 5, wherein the catalyst is selected from the group consisting of: iron salts, cobalt salts and nickel salts.

### Claim 7 (depends on 1)

The method according to claim 1, wherein the heat treatment is sintering.

### Claim 8 (depends on 7)

The method according to claim 7, wherein the sintering is performed in a hydrogen-containing atmosphere.

### Claim 9 (depends on 7)

The method according to claim 7, wherein the sintering is performed at a temperature in the range of from 600° C. to 950° C.