Metal paste for gas sensor electrode formation

Patent metadata

Field	Value
Publication number	US-10106691-B2
Application number	US-201715661886-A
Country	US
Kind code	B2
Filing date	Jul 27, 2017
Priority date	Jan 28, 2013
Publication date	Oct 23, 2018
Grant date	Oct 23, 2018

Abstract

To be provided is a metal paste from which an electrode having high electrode activity as a sensor electrode of various gas sensors can be produced. The present invention is a metal paste for forming a gas sensor electrode obtained by dispersing a conductive particle including Pt or a Pt alloy and a ceramic powder including zirconia or stabilized zirconia, or any of zirconia and stabilized zirconia and one or more oxides of La, Ce, Pr, Nd, Sm, and Hf in a solvent, the metal paste further including an inorganic oxide particle containing alumina and an insoluble particle that is insoluble in the solvent, in which 0.5 or more to 3.0 mass % or less of the inorganic oxide particle and 1.0 to 5.0 mass % of the insoluble particle are dispersed based on the mass of the solid content of the conductive particle, the ceramic powder, the inorganic oxide particle, and the insoluble particle.

First claim

What is claimed is:

1. A metal paste for forming a gas sensor electrode, the metal paste consisting of a dispersion of:
a) a conductive particle consisting of Pt or a Pt alloy,
b) a ceramic powder consisting of zirconia or stabilized zirconia, or any of zirconia and stabilized zirconia and one or more oxides of La, Ce, Pr, Nd, Sm, and Hf in a solvent,
c) an inorganic oxide particle consisting of alumina, and
d) an insoluble particle that is insoluble in the solvent, wherein the insoluble particle is one or more selected from the group consisting of graphite and diamond powder,
wherein 0.5 to 3.0 mass % of the inorganic oxide particle and 1.0 to 15.0 mass % of the insoluble particle are dispersed based on mass of solid content of the conductive particle, the ceramic powder, the inorganic oxide particle, and the insoluble particle to form the gas sensor electrode.

2. The metal paste for forming a gas sensor electrode according to claim 1 , wherein the insoluble particle consists of diamond powder.

3. The metal paste for forming a gas sensor electrode according to claim 2 , wherein 8.0 to 13.5 mass % of the insoluble particle is dispersed based on mass of solid content of the conductive particle, the ceramic powder, the inorganic oxide particle, and the insoluble particle to form the gas sensor electrode.

4. The metal paste for forming a gas sensor electrode according to claim 3 , wherein a particle diameter of the insoluble particle is 0.5 to 1.4 μm.

5. The metal paste for forming a gas sensor electrode according to claim 4 , wherein a particle diameter of the conductive particle is 5 nm to 2 μm.

6. The metal paste for forming a gas sensor electrode according to claim 4 , wherein a particle diameter of the ceramic powder is 100 to 500 nm.

7. The metal paste for forming a gas sensor electrode according to claim 4 , wherein a particle diameter of the inorganic oxide particle is 5 to 500 nm.

8. The metal paste for forming a gas sensor electrode according to claim 3 , wherein a particle diameter of the conductive particle is 5 nm to 2 μm, a particle diameter of the ceramic powder is 100 to 500 nm, a particle diameter of the inorganic oxide particle is 5 to 500 nm, and a particle diameter of the insoluble particle is 0.5 to 1.4 μm.

9. The metal paste for forming a gas sensor electrode according to claim 4 , wherein a particle diameter of the conductive particle is 5 nm to 2 μm, a particle diameter of the ceramic powder is 100 to 500 nm, and a particle diameter of the inorganic oxide particle is 5 to 500 nm.

10. The metal paste for forming a gas sensor electrode according to claim 1 , wherein 5.0 to 15.0 mass % of the insoluble particle is dispersed based on mass of solid content of the conductive particle, the ceramic powder, the inorganic oxide particle, and the insoluble particle to form the gas sensor electrode.

11. The metal paste for forming a gas sensor electrode according to claim 1 , wherein a dispersed amount of the ceramic powder is 10 to 20 mass % based on the mass of the solid content.

12. The metal paste for forming a gas sensor electrode according to claim 1 , wherein the conductive particle comprises any of Pt and a Pt—Pd alloy containing 30 mass % or less of Pd.

13. The metal paste for forming a gas sensor electrode according to claim 1 , wherein the solvent is one or more kinds of ethylene glycol, propylene glycol, ethylene glycol monophenyl ether, benzyl alcohol, kerosene, paraffin, γ-butyrolactone, N-methyl pyrrolidone, butyl carbitol, turpentine oil, α-terpineol, and terpineol.

14. The metal paste for forming a gas sensor electrode according to claim 1 , wherein a particle diameter of the conductive particle is 5 nm to 2 μm.

15. The metal paste for forming a gas sensor electrode according to claim 1 , wherein a particle diameter of the ceramic powder is 100 to 500 nm.

16. The metal paste for forming a gas sensor electrode according to claim 1 , wherein a particle diameter of the inorganic oxide particle is 5 to 500 nm.

17. The metal paste for forming a gas sensor electrode according to claim 1 , wherein a particle diameter of the insoluble particle is 0.5 to 3 μm.

18. The metal paste for forming a gas sensor electrode according to claim 1 , wherein a particle diameter of the conductive particle is 5 nm to 2 μm, a particle diameter of the ceramic powder is 100 to 500 nm, a particle diameter of the inorganic oxide particle is 5 to 500 nm, and a particle diameter of the insoluble particle is 0.5 to 3 μm.

Assignees

• Tanaka Precious Metal Ind

Inventors

• Okamoto Nobuhisa
• Hosoi Takuya
• Akiyama Nobuyuki
• Nakai Akihiro
• Onozumi Shigekazu

Classifications

• G01N27/4045

  for gases other than oxygen · CPC title

• C04B2235/3225

  Yttrium oxide or oxide-forming salts thereof · CPC title

• G01N27/4073

  Composition or fabrication of the solid electrolyte · CPC title

• G01N27/4075

  Composition or fabrication of the electrodes and coatings thereon, e.g. catalysts · CPC title

• B22F2301/25

  Noble metals, i.e. Ag Au, Ir, Os, Pd, Pt, Rh, Ru · CPC title