# US 7,744,779 B2 · Nickel-rhenium alloy powder and conductor paste containing the same

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- Number: US 7,744,779 B2
- Document ID: US7744779B2
- Status: Granted
- Kind: B2
- Application number: 12/310,745
- Filed: 2007-09-25
- Published: 2010-01-28
- Granted: 2010-06-29
- Earliest claimed: 2006-10-02
- Assignees: Shoei Chemical Inc.
- Inventors: Yuji Akimoto; Kazuro Nagashima; Tetsuya Kimura; Yasuhiro Kamahori
- Web page: https://patentgrep.com/patent/US7744779B2

## CPC

- H01G 4/008: Selection of materials
- B22F 1/16: Metallic particles coated with a non-metal (coated with lubricating or binding agents or with organic material B22F1/10)
- H01B 1/22: the conductive material comprising metals or alloys
- H01G 4/0085: {Fried electrodes}
- B22F 2998/00: Supplementary information concerning processes or compositions relating to powder metallurgy
- H01F 27/292: {Surface mounted devices}
- H01G 4/30: Stacked capacitors (H01G4/33 takes precedence)
- H10W 70/666: {Organic materials or pastes}
- Y10T 428/2991: Coated
- H01G: CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE (selection of specified materials as dielectric H01B3/00; capacitors having potential barriers H10D1/62, H10K10/10)
- 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
- 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})
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A nickel-rhenium alloy powder comprising nickel as a main component, 0.1 to 10% by weight of rhenium, and having an average particle size of 0.05 to 1.0 μm is provided. The nickel-rhenium alloy powder has a surface oxide film containing a nickel oxide and a rhenium oxide, and the amount of oxygen in the surface oxide film is 0.1 to 3.0% by weight relative to the total weight of the powder. The nickel-rhenium alloy powder is suitable, in particular, for forming internal electrode layers of a multilayer ceramic electronic component. The obtained powder is homogeneously mixed and dispersed in an organic vehicle, together with other additives as needed, to prepare a conductor paste. The surface oxide film allows bringing the sintering shrinkage behavior of electrode layers and ceramic layers closer to each other when the nickel-rhenium alloy powder is used, in particular, for forming internal electrodes of a multilayer ceramic electronic component. Moreover, there occurs no electrode spheroidizing caused by oversintering. and thus thinner, dense internal electrodes having excellent continuity can be formed.

## Claims

### Claim 1

A nickel-rhenium alloy powder comprising nickel as a main component, 0.1 to 10% by weight of rhenium, and having an average particle size of 0.05 to 1.0 μm, wherein the nickel-rhenium alloy powder has a surface oxide film comprising a nickel oxide and a rhenium oxide, and an amount of oxygen in the surface oxide film is 0.1 to 3.0% by weight relative to a total weight of the powder.

### Claim 2 (depends on 1)

The nickel-rhenium alloy powder according to claim 1, wherein in a TMA measurement performed by heating the nickel-rhenium alloy powder from room temperature to 1300° C. at a rate of 5° C./min in a nitrogen-hydrogen reducing atmosphere, the temperature at which the powder exhibits a 20% shrinkage rate, relative to the shrinkage rate at 1300° C., ranges from 400 to 800° C.

### Claim 3 (depends on 1)

The nickel-rhenium alloy powder according to claim 1, wherein a silicon oxide is present in the surface oxide film.

### Claim 4 (depends on 1)

The nickel-rhenium alloy powder according to claim 1, wherein the nickel-rhenium alloy powder further contains sulfur.

### Claim 5 (depends on 4)

The nickel-rhenium alloy powder according to claim 4, wherein the sulfur segregates near the surface of the powder.

### Claim 6 (depends on 4)

The nickel-rhenium alloy powder according to claim 4, wherein a content of the sulfur is 100 to 2,000 ppm, in terms of sulfur atoms, relative to the total weight of the powder.

### Claim 7 (depends on 1)

A conductor paste for forming internal electrodes of a multilayer ceramic electronic component, comprising at least the nickel-rhenium alloy powder according to claim 1, as a conductive powder.