Tungsten electrode material and thermionic emission current measuring device

Patent metadata

Field	Value
Publication number	US-9502201-B2
Application number	US-200913133338-A
Country	US
Kind code	B2
Filing date	Dec 8, 2009
Priority date	Dec 8, 2008
Publication date	Nov 22, 2016
Grant date	Nov 22, 2016

Abstract

Provided is a tungsten electrode material that can improve the life of an electrode than conventional by the use of a material in place of thorium oxide. The tungsten electrode material includes a tungsten base alloy and oxide particles dispersed in the tungsten base alloy, wherein the oxide particle is an oxide solid solution in which a Zr oxide and/or a Hf oxide and an oxide of at least one or more kinds of rare earth elements selected from Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu are solid-dissolved.

First claim

The invention claimed is:

1. A tungsten electrode material comprising
a tungsten base alloy, and
oxide particles dispersed in the tungsten base,
wherein each oxide particle is an oxide solid solution in which a Zr oxide and/or a Hf oxide and at least one or more kinds of rare earth oxides selected from Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu are solid-dissolved, and
wherein in a cross-section in an axial direction of the tungsten electrode material, an area ratio of those oxide solid solutions, each having a cross-section whose aspect ratio is 6 or more, is 4% or more of a cross-sectional area of all the oxide solid solutions.

2. The tungsten electrode material according to claim 1 , wherein the content of the oxide solid solutions is 0.5 mass % to 5 mass % and the balance is substantially tungsten.

3. The tungsten electrode material according to claim 1 , wherein a ratio of the rare earth oxides to a total amount of the Zr oxide and/or the Hf oxide and the rare earth oxides is 65 mol % or less (excluding 0 mol %).

4. The tungsten electrode material according to claim 1 , wherein
in a cross-section in an axial direction of the tungsten electrode material, a cross-sectional area of those oxide solid solutions, each having a cross-section whose long axis direction forms an angle of 20° or less with the axial direction, is 50% or more of a cross-sectional area of all the oxide solid solutions.

5. The tungsten electrode material according to claim 1 , wherein
in a cross-section in an axial direction of the tungsten electrode material, a total area of those oxide solid solutions, each having a cross-section with a circle-converted particle size of 5 μm or less, is less than 50% of an area of all the oxide solid solutions.

6. The tungsten electrode material according to claim 1 , wherein the tungsten electrode material contains the oxide solid solutions which show a relationship where, in the elements forming the oxide solid solutions, a standard deviation σ of ratios of total moles of Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu to total moles of the elements in the oxide solid solutions excluding oxygen is σ≦0.025.

Assignees

• Nakabayashi Seiji
• Katoh Masahiro
• Yamamoto Yoshiharu
• Yoshida Toshihiko
• Hasegawa Norihiko
• Almt Corp

Inventors

• Nakabayashi Seiji
• Katoh Masahiro
• Yamamoto Yoshiharu
• Yoshida Toshihiko
• Hasegawa Norihiko

Classifications

• H01J61/0735

  characterised by the material of the electrode · CPC title

• H01J9/42

  Measurement or testing during manufacture · CPC title

• H01J61/0737

  characterised by the electron emissive material · CPC title

• H01J1/146 Primary

  with metals or alloys as an emissive material · CPC title

• H01B1/08

  oxides · CPC title