Tungsten alloy, tungsten alloy part, discharge lamp, transmitting tube, and magnetron

Patent metadata

Field	Value
Publication number	US-10167536-B2
Application number	US-201715784416-A
Country	US
Kind code	B2
Filing date	Oct 16, 2017
Priority date	Dec 20, 2011
Publication date	Jan 1, 2019
Grant date	Jan 1, 2019

Abstract

According to one embodiment, a tungsten alloy includes a W component and a Hf component including HfC. A content of the Hf component in terms of HfC is 0.1 wt % or more and 3 wt % or less.

First claim

The invention claimed is:

1. A method for producing a tungsten alloy for a discharge lamp, a transmitting tube or a magnetron, the method comprising:
mixing a HfC powder comprising primary particles having an average particle diameter of 15 μm or less and a tungsten powder having an average particle diameter of 0.5 to 10 μm to obtain a raw powder;
molding the raw powder to obtain a molded body;
sintering the molded body to obtain a sintered body; and
performing at least one process selected from the group consisting of forging, rolling, wiredrawing, cutting, and polishing, after the sintering step;
wherein a processing ratio [(A−B)/A]×100 of the at least one process is within a range of 30 to 90%, wherein A is a sectional area of the sintered body before the at least one process and B is a sectional area of the sintered body after the at least one process.

2. The method according to claim 1 , wherein a content of the HfC powder in the raw powder is 0.1 to 3 wt %.

3. The method according to claim 1 , wherein the raw powder comprises 0.01 wt % or less of a dope material which is at least one element selected from the group consisting of K, Si, and Al.

4. The method according to claim 1 , wherein an average particle diameter of the HfC powder is equal to or smaller than the average particle diameter of the tungsten powder.

5. The method according to claim 1 , wherein the sintering is performed at a temperature of 1400 to 3000° C. for 1 to 20 hours.

6. The method according to claim 1 , wherein the sintering comprises presintering of the molded body at a temperature of 1250 to 1500° C. to obtain a presintered body and electric sintering of the presintered body at a temperature of 2100 to 2500° C.

7. The method according to claim 1 , further comprising performing a stress relief heat treatment at a temperature of 1300 to 2500° C. after the at least one process.

8. The method according to claim 1 , wherein the average particle diameter of the HfC powder is less than the average particle diameter of the tungsten powder.

Assignees

• Toshiba Kk
• Toshiba Materials Co Ltd

Inventors

• Yamamoto Shinichi
• Nakano Kayo
• Horie Hiromichi
• Sano Takashi
• Minami Yoshiko
• Yamaguchi Satoshi

Classifications

• C22C43/00

  Alloys containing radioactive materials · CPC title

• C22F1/18

  High-melting or refractory metals or alloys based thereon · CPC title

• B22F3/1007

  Atmosphere (B22F3/1021 takes precedence) · CPC title

• C22C1/045

  Alloys based on refractory metals · CPC title

• H01J23/05

  having a cylindrical emissive surface, e.g. cathodes for magnetrons · CPC title