Method for cold gas spraying

Patent metadata

Field	Value
Publication number	US-9527069-B2
Application number	US-201314369002-A
Country	US
Kind code	B2
Filing date	Jan 17, 2013
Priority date	Jan 24, 2012
Publication date	Dec 27, 2016
Grant date	Dec 27, 2016

Abstract

The invention relates to a method for cold gas spraying in which a spray powder containing photocatalytically active spray particles is accelerated by means of a carrier gas in a nozzle and forms a coating upon striking a substrate. According to the invention, the method is characterized in that at least one part of the photocatalytically active spray particles consists of nanocrystalline agglomerates having a porosity of 200 to 800 m 2 /g, the porosity being determined by means of a BHT measurement with nitrogen. Coatings produced with the method according to the invention and objects having such a coating are also claimed.

First claim

What we claim is:

1. A method for cold gas spraying, in which a spray powder containing photocatalytically active spray particles is accelerated in a nozzle by means of a carrier gas and forms a coating upon impact with a substrate, characterized in that at least a part of the photocatalytically active spray particles consists of nanocrystalline agglomerates that have a porosity from 200 to 800 m 2 /g, wherein the porosity is determined by a BET measurement using nitrogen and the nanocrystalline agglomerates have been sintered to a hardness of between 0.1 and 4 GPa, wherein the hardness is measured with a nanoindenter.

2. The method according to claim 1 , characterized in that the carrier gas has a temperature higher than 400° C. upstream of the nozzle throat.

3. The method according to claim 1 , characterized in that the carrier gas is selected from, the group consisting of nitrogen, helium and mixtures thereof.

4. The method according to claim 1 , characterized in that the nanocrystalline agglomerates contain a compound selected from the group consisting of titanium dioxide (TiO 2 ), tungsten trioxide (WO 3 ), strontium titanate (SrTiO 3 ), tin dioxide (SnO 2 ), silicon carbide (SiC), sodium tantalum oxide (NaTaO), zinc oxide (ZnO), alpha ferric oxide (α-Fe 2 O 3 ), bismuth vanadate (BiVO 4 ), tantalum oxynitride (TaON), (III)tantalum(V)nitride (Ta 3 N 5 ), indium tantalum(IV) oxide (InTaO 4 ) and indium niobium(IV)oxide (InNbO 4 ).

5. The method according to claim 1 , characterized in that the nanocrystalline agglomerates have a porosity from 250to 600 m 2 /g.

6. The method according to claim 1 , characterized in that at least the photocatalytically active spray particles of nanocrystalline agglomerates are heated in a pre-chamber or in an elongated convergent region by means of the carrier gas.

7. The method according to claim 1 , characterized in that coatings having photocatalytic activity in visible light are produced.

8. The method according to claim 1 , characterized in that the coating is at least 80 μm thick.

9. A coating prepared by the process according to claim 1 .

10. The coating according to claim 9 that is photocatalytically active in visible light.

11. The coating according to claim 9 or consisting of titanium dioxide.

12. The coating according to claims 9 having a thickness which is greater than a layer of spray particles.

13. An object that has a coating according to claim 9 .

14. The object according to claim 13 , characterized in that an adhesive layer which is responsible for ensuring adhesion between the article to be coated and the coating is applied underneath the coating, on the article that is to be coated.

15. The method according to claim 2 characterized in that the carrier gas has a temperature higher than 800° C. upstream of the nozzle throat.

16. The method according to claim 2 characterized in that the carrier gas has a temperature higher that 900° C. upstream of the nozzle throat.

17. The method according to claim 4 characterized in that the compound is titanium dioxide in the anatase form.

18. The method according to claim 1 characterized in that the hardness is between 0.2 to 2 GPa wherein the hardness is measured with a nanoindenter.

19. The method according to claim 5 characterized in that the nanocrystalline agglomerates have a porosity from 280 to 450 m 2 /g.

20. The method according to claim 8 characterized in that the coating is at least 100 μm thick.

21. The coating according to claim 12 characterized in that the thickness is at least 80 μm.

22. The coating according to claim 12 characterized in that the thickness is at least 100 μm.

Assignees

• Heinrich Peter
• Krömmer Werner
• Gärtner Frank
• Klassen Thomas
• Kliemann Jan-Oliver
• Gutzmann Henning
• Yamada Motohiro
• Linde Ag

Inventors

• Heinrich Peter
• Krömmer Werner
• Gärtner Frank
• Klassen Thomas
• Kliemann Jan-Oliver
• Gutzmann Henning
• Yamada Motohiro

Classifications

• C23C24/08

  by application of heat or pressure and heat (C23C24/04 takes precedence) · CPC title

• C23C24/082

  without intermediate formation of a liquid in the layer · CPC title

• B01J37/0221 Primary

  of particles · CPC title

• C01G23/047

  Titanium dioxide · CPC title

• B05B7/162

  and heat being transferred from the atomising fluid to the material to be sprayed · CPC title