Spinel powder and manufacturing process therefor, and processes for producing thermal spraying film and gas sensor elements

Patent metadata

Field	Value
Publication number	US-9340680-B2
Application number	US-201214113453-A
Country	US
Kind code	B2
Filing date	Mar 29, 2012
Priority date	Apr 28, 2011
Publication date	May 17, 2016
Grant date	May 17, 2016

Abstract

Disclosed is a spinel powder obtained by mixing a magnesia raw-material with an electrically fused alumina, followed by firing of the mixture. The particles of the spinel powder are coated with granular spinel particles. Therefore, there are provided a spinel powder and a simple method for producing the same, which is superior in thermal spraying property and has a unique particle shape. In particular, there is provided a method for producing a spinel powder which contributes to a reduction in the variation of characteristics of sensors, for example, as a thermal spraying powder for forming a protective coating of a gas sensor element.

First claim

The invention claimed is:

1. A spinel powder coated with granular spinel particles, wherein the granular spinel particles are from 0.1 to 4 μm, and the spinel powder has a mean particle diameter D50 of 10 to 70 μm and a specific surface area of 0.2 to 2 m 2 /g.

2. The spinel powder according to claim 1 , wherein the spinel powder has an alumina content of 69 to 82% and a magnesia content of 18 to 31%.

3. The spinel powder according to claim 1 , wherein the spinel powder has X-ray diffraction intensity ratios:
a ratio I[αAl 2 O 3 (113)]/{I[αAl 2 O 3 (113)]+I[MgAl 2 O 4 (311)]} of 0.03 or less, and
a ratio I[MgO(200)]/{I[MgO(200)]+I[MgAl 2 O 4 (311)]} of 0.03 or less.

4. A method for producing a spinel powder according to claim 1 , which comprises mixing a magnesia raw-material with an electrically fused alumina, followed by firing of the mixture.

5. The method for producing a spinel powder according to claim 4 , wherein the spinel powder has an alumina content of 69 to 82% and a magnesia content of 18 to 31%.

6. The method for producing a spinel powder according to claim 4 , wherein the electrically fused alumina has a mean particle diameter D50 of 7 to 70 μm and the magnesia raw-material has a mean particle diameter D50 of 1 to 10 μm.

7. A method for producing a thermal sprayed film, which comprises performing thermal spraying using a spinel powder described in claim 1 , the spinel powder being produced by mixing a magnesia raw-material with an electrically fused alumina, followed by firing of the mixture.

8. A method for producing a gas sensor element, which comprises forming an electrode-protecting film of the gas sensor element using a spinel powder described in claim 1 , the spinel powder being produced by mixing a magnesia raw-material with an electrically fused alumina, followed by firing of the mixture.

9. The spinel powder according to claim 2 , wherein the spinel powder has X-ray diffraction intensity ratios:
a ratio I[αAl 2 O 3 (113)]/{I[αAl 2 O 3 (113)]+I[MgAl 2 O 4 (311)]} of 0.03 or less, and
a ratio I[MgO(200)]/{I[MgO(200)]+I[MgAl 2 O 4 (311)]} of 0.03 or less.

10. The method for producing a spinel powder according to claim 2 , which comprises mixing a magnesia raw-material with an electrically fused alumina, followed by firing of the mixture.

11. The method for producing a spinel powder according to claim 3 , which comprises mixing a magnesia raw-material with an electrically fused alumina, followed by firing of the mixture.

12. The method for producing a spinel powder according to claim 5 , wherein the electrically fused alumina has a mean particle diameter D50 of 7 to 70 μm and the magnesia raw-material has a mean particle diameter D50 of 1 to 10 μm.

13. A method for producing a thermal sprayed film, which comprises performing thermal spraying using a spinel powder described in claim 2 , the spinel powder being produced by mixing a magnesia raw-material with an electrically fused alumina, followed by firing of the mixture.

14. A method for producing a thermal sprayed film, which comprises performing thermal spraying using a spinel powder described in claim 3 , the spinel powder being produced by mixing a magnesia raw-material with an electrically fused alumina, followed by firing of the mixture.

15. A method for producing a gas sensor element, which comprises forming an electrode-protecting film of the gas sensor element using a spinel powder described claim 2 , the spinel powder being produced by mixing a magnesia raw-material with an electrically fused alumina, followed by firing of the mixture.

16. A method for producing a gas sensor element, which comprises forming an electrode-protecting film of the gas sensor element using a spinel powder described claim 3 , the spinel powder being produced by mixing a magnesia raw-material with an electrically fused alumina, followed by firing of the mixture.

Assignees

• Fujii Namitsugu
• Nishizawa Ryo
• Nabeta Takuji
• Daiichi Kigenso Kagaku Kogyo
• Denso Corp

Inventors

• Fujii Namitsugu
• Nishizawa Ryo
• Nabeta Takuji

Classifications

• C01P2002/32

  spinel-type (AB2O4) · CPC title

• C01P2006/12

  Surface area · CPC title

• C23C4/11

  Oxides · CPC title

• G01N27/407 Primary

  for investigating or analysing gases {(G01N27/411 takes precedence)} · CPC title

• C01P2004/51

  Particles with a specific particle size distribution · CPC title