# US 10,121,597 B2 · Tantalum wire used for anode lead of tantalum capacitor and manufacturing method thereof

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- Number: US 10,121,597 B2
- Document ID: US10121597B2
- Status: Granted
- Kind: B2
- Application number: 14/882,249
- Filed: 2015-10-13
- Published: 2016-02-04
- Granted: 2018-11-06
- Earliest claimed: 2009-01-20
- Assignees: Ningxia Orient Tantalum Industry Co., Ltd.
- Applicants: Ningxia Orient Tantalum Industry Co., Ltd.
- Inventors: Bing Zhao; Linghui Du; Yongxu Xie; Qingfeng Wan; Huifeng Wang; Guohua Qiu
- Web page: https://patentgrep.com/patent/US10121597B2

## CPC

- H01G 9/0029: {Processes of manufacture}
- B21B 1/18: in a continuous process
- B22F 3/24: After-treatment of workpieces or articles {(B22F3/1146 takes precedence)}
- B22F 5/12: of wires {(of tubes B22F5/10)}
- H01G 9/012: specially adapted for solid capacitors
- H01G 9/048: characterised by their structure (H01G11/22 takes precedence)
- B21B 1/16: for rolling {wire rods, bars, merchant bars, rounds} wire or material of like small cross-section
- B22F 2998/10: Processes characterised by the sequence of their steps
- B22F 2999/00: Aspects linked to processes or compositions used in powder metallurgy
- H01G 9/052: Sintered electrodes
- Y10T 29/49204: Contact or terminal manufacturing
- 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)
- B21B: ROLLING OF METAL (auxiliary operations used in connection with metal-working operations covered in B21, see B21C; bending by rolling B21D; manufacture of particular objects, e.g. screws, wheels, rings, barrels, balls, by rolling B21H; pressure welding by means of a rolling mill B23K20/04)
- 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
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

The present invention relates to a tantalum wire for anode lead of tantalum capacitors, characterized in that the cross section of the tantalum wire is approximate rectangular or regular rectangular. The present invention also relates to a process for manufacturing the tantalum wire, comprising the steps of: providing feedstock tantalum wire; subjecting the feedstock tantalum wire to heat treatment; subjecting the heat treated tantalum wire to surface pretreatment to form an oxide membrane on the surface-pretreated tantalum wire; rolling the surface-pretreated tantalum wire by lubricating with lubricant oil to make the cross section of the rolled tantalum wire being approximate rectangular or regular rectangular; subjecting the tantalum wire to final annealing.

## Claims

### Claim 1

A process for manufacturing a tantalum wire, comprising the steps of:
subjecting a feedstock tantalum wire to a heat treatment to form a heat-treated tantalum wire;
subjecting the heat-treated tantalum wire to a surface pretreatment to form an oxide membrane on the heat-treated tantalum wire to form a surface-pretreated tantalum wire;
rolling the surface-pretreated tantalum wire that is coated with the oxide membrane while lubricating with a lubricant oil to form a rolled tantalum wire with a cross section of the rolled tantalum wire being rectangular with curved corners; and
annealing the rolled tantalum wire, wherein
the surface pretreatment is performed at a temperature of 500-700° C. in 99% pure oxygen atmosphere for 1 minute to 1 hour.

### Claim 2 (depends on 1)

The process according to claim 1, wherein the heat treatment includes a vacuum annealing at a temperature of 1000-1450° C. for 30-60 minutes.

### Claim 3 (depends on 1)

The process according to claim 1, wherein the rolling includes a plurality of passes and a reduction rate of each pass is 20-95%.

### Claim 4 (depends on 1)

The process according to claim 1, wherein the annealing is intervened by the rolling to eliminate stress.

### Claim 5 (depends on 1)

The process according to claim 1, wherein the annealing includes a vacuum annealing at a temperature of 1000-1450° C. for 30-60 minutes.

### Claim 6 (depends on 1)

The process according to claim 1, wherein the rolled tantalum wire is cleaned after the rolling and before a final step of the annealing.

### Claim 7 (depends on 1)

The process according to claim 1, wherein a final step of the annealing is a continuous wire drawing annealing with an annealing temperature of 1600-2000° C. and a wire drawing rate of 5-10 meters per minute.

### Claim 8 (depends on 1)

The process according to claim 1, wherein the lubricant oil is an organic fluoro-chloro lubricant oil.

### Claim 9 (depends on 1)

The process according to claim 1, wherein the heat treatment is performed at a temperature equal to or higher than a crystallization temperature of the feedstock tantalum wire.

### Claim 10 (depends on 2)

The process according to claim 2, wherein the vacuum annealing is at a temperature of 1200-1400° C. for 40-60 minutes.

### Claim 11 (depends on 1)

The process according to claim 1, wherein the surface pretreatment is performed at the temperature of 500-700° C. in 99% pure oxygen atmosphere for 5-30 minutes.

### Claim 12 (depends on 3)

The process according to claim 3, wherein the reduction rate of each pass is 20-90%.

### Claim 13 (depends on 12)

The process according to claim 12, wherein the reduction rate of each pass is 22-85%.

### Claim 14 (depends on 5)

The process according to claim 5, wherein the vacuum annealing is at a temperature of 1200-1400° C. for 40-60 minutes.

### Claim 15 (depends on 7)

The process according to claim 7, wherein the final step of the annealing is performed at an annealing temperature of 1700-1800° C.

### Claim 16 (depends on 1)

The process according to claim 1, wherein the annealing is performed at a temperature equal to or higher than a recrystallization temperature of the rolled tantalum wire in an inert gas atmosphere.

### Claim 17 (depends on 1)

The process according to claim 1, wherein the rolling is performed by at least one of a grooved roller, a flat roller, an arc-shaped roller, and a convex roller.