Plasma spraying device and a method for introducing a liquid precursor into a plasma gas stream

• US 20080057212A1
• Filed: 06/19/2007
• Published: 03/06/2008
• Est. Priority Date: 08/30/2006
• Status: Active Grant

• Current Assignee: Brass Craft Manufacturing Co (Masco Corporation)
• Original Assignee: Oerlikon Metco AG (OC Oerlikon Corporation AG)
• Inventors: Barbezat, Gerard, Dorier, Jean-Luc, Hollenstein, Christoph, Refke, Arno
• Granted Patent: US 8,001,927 B2
• Time in Patent Office: Days
• US Class Current: 427/446
• CPC Class Codes: C23C 4/134 Plasma spraying
• CPC Class Codes: H05H 1/34 Details, e.g. electrodes, nozzles
• CPC Class Codes: H05H 1/3484 Convergent-divergent nozzles
• CPC Class Codes: H05H 1/42 with provisions for introducing materials into the plasma, e.g. powder, liquid arc stabilising or constricting arrangements H05H1/3405; coaxial protecting fluids H05H1/341; electrostatic spraying, spraying apparatus with means for charging the spray electrically B05B5/00 ; cf. B23K9/324, B05B7/22
• CPC Class Codes: Y10T 137/0346 Controlled by heat of combustion of mixture

Abstract

The invention relates to a plasma spraying device (1) for spraying a coating (2) onto a substrate (3) by a thermal spray process. Said plasma spraying device (1) includes a plasma torch (4) for heating up a plasma gas (5) in a heating zone (6), wherein the plasma torch (4) includes a nozzle body (7) for forming a plasma gas stream (8), and said plasma torch (4) having an aperture (9) running along a central longitudinal axis (10) through said nozzle body (7). The aperture (9) has an convergent section (11) with an inlet (12) for the plasma gas (5), a throat section (13) including a minimum cross-sectional area of the aperture, and a divergent section (14) with an outlet (15) for the plasma gas stream (8), wherein an introducing duct (16) is provided for introducing a liquid precursor (17) into the plasma gas stream (8). According to the invention a penetration means (18, 161, 181, 182) is provided to penetrate the liquid precursor (17) inside the plasma gas stream (8). The invention relates also to method for introducing a liquid precursor (17) into a plasma gas stream (8) as well as to the use of a plasma spraying device (1) and a method in accordance with the present invention for coating a surface of a substrate (3).

Claims

1. Plasma spraying device for spraying a coating (2) onto a substrate (3) by a thermal spray process, said plasma spraying device including a plasma torch (4) for heating up a plasma gas (5) in a heating zone (6), wherein the plasma torch (4) includes a nozzle body (7) for forming a plasma gas stream (8), said plasma torch (4) having an aperture (9) running along a central longitudinal axis (10) through said nozzle body (7), which aperture (9) has an convergent section (11) with an inlet (12) for the plasma gas (5), a throat section (13) including a minimum cross-sectional area of the aperture, and a divergent section (14) with an outlet (15) for the plasma gas stream (8), wherein an introducing duct (16) is provided for introducing a liquid precursor (17) into the plasma gas stream (8), characterized in that a penetration means (18, 161, 181, 182) is provided to penetrate the liquid precursor (17) inside the plasma gas stream (8).

2. Plasma spraying device in accordance with claim 1, wherein the introducing duct (16) is provided between the convergent section (11) and the divergent section (14) of the aperture (9), in particular at the minimum cross-sectional area of the aperture (9) and/or wherein the introducing duct (16) is provided between the inlet (12) of the convergent section (11) and the minimum cross-sectional area of the aperture (9) and/or wherein the introducing duct (16) is provided between the minimum cross-sectional area of the aperture (9) and the outlet (15) of the divergent section (14).

3. Plasma spraying device in accordance with claim 1, wherein the penetration means (18) is a penetration groove (181), being provided at an inner wall (19) of the nozzle body (7), in particular a circumferential penetration groove (181).

4. Plasma spraying device in accordance with claim 1, wherein the penetration groove (181) is provided between the convergent section (11) and the divergent section (14) of the aperture (9), in particular at the minimum cross-sectional area of the aperture (9) and/or wherein the penetration groove (181) is provided between the inlet (12) of the convergent section (11) and the minimum cross-sectional area of the aperture (9) and/or wherein the penetration groove (181) is provided between the minimum cross-sectional area of the aperture (9) and the outlet (15) of the divergent section (14).

5. Plasma spraying device in accordance with claim 1, wherein the penetration grove (181) has a triangular shape and/or has a width (1811) of 0.5 mm to 3 mm, in particular between 1 mm and 2 mm, especially 1.5 mm and/or has a depth (1812) of 0.05 mm to 2 mm, in particular between 0.75 mm and 1.5 mm, preferably 1 mm.

6. Plasma spraying device in accordance with claim 1, wherein the penetration means (18) is provided by the introducing duct (16) being designed as a nebulizer (161).

7. Plasma spraying device in accordance with claim 1, wherein the nebulizer (161) is provided between the convergent section (11) and the divergent section (14) of the aperture (9), in particular at the minimum cross-sectional area of the aperture (9) and/or wherein the nebulizer (161) is provided between the inlet (12) of the convergent section (11) and the minimum cross-sectional area of the aperture (9) and/or wherein the nebulizer (161) is provided between the minimum cross-sectional area of the aperture (9) and the outlet (15) of the divergent section (14).

8. Plasma spraying device in accordance with claim 1, wherein the penetration means (18) is provided by the introducing duct (16) being designed as a capillary (182) having an injection hole (183) with reduced diameter.

9. Plasma spraying device in accordance with claim 1, wherein the capillary (182) is provided between the convergent section (11) and the divergent section (14) of the aperture (9), in particular at the minimum cross-sectional area of the aperture (9) and/or wherein the capillary (182) is provided between the inlet (12) of the convergent section (11) and the minimum cross-sectional area of the aperture (9) and/or wherein the capillary (182) is provided between the minimum cross-sectional area of the aperture (9) and the outlet (15) of the divergent section (14).

10. Plasma spraying device in accordance with claim 1, wherein an introducing angle (α

) of the introducing duct (16) is between 20° and

150°

, in particular between 45° and

135°

, preferably between 70° and

110°

, especially about 90°

.

11. Plasma spraying device in accordance with claim 1, wherein the introducing duct (16) and/or the penetration means (18), in particular the nebulizer (161), is made of PFA and or of other materials.

12. Plasma spraying device in accordance with claim 1, including a supply unit (19) to supply the liquid precursor (17).

13. Plasma spraying device in accordance with claim 12, wherein the supply unit (19) includes a reservoir for the liquid precursor (17) and/or a reservoir for a carrier gas and/or a reservoir pressurization for pressurizing the liquid precursor (17) by the carrier gas and/or a metering device, in particular a liquid and/or gas flow meter, especially a mass flow meter, for metering the flow of the liquid precursor and/or the carrier gas.

14. Plasma spraying device in accordance with claim 12, wherein the liquid precursor (17) is a slurry, and/or a suspension, and/or the fluid is water, and/or an acid, and/or an alkali fluid, and/or an organic fluid, in particular methanol, and/or an salt solution, and/or an organosilicon and/or another coating fluid (17), and/or the liquid precursor (17) is a suspension or a slurry, in particular a liquid precursor (17) comprising nanoparticles and/or an solution or mixing of the aforementioned liquid precursor (17).

26. Use of a plasma spraying device (1) made in accordance with claim 1 for coating a surface of a substrate (3) or a device (3), a carbon coating, especially a Diamond Like Carbon Coating, and/or a carbide coating and/or a nitride coating and/or a composite coating and/or a nanostructured coating, in particular a surface of a photovoltaic device (3), especially a solar cell, and/or for providing a coating, in particular a functional coating on a substrate (3), in particular on a glass substrate or on a semiconductor, especially on a silicon substrate (3), in more particular on a wafer comprising electronic elements and/or for providing a functional coating on textiles.

15. Method for introducing a liquid precursor (17) into a plasma gas stream (8) using a plasma spraying device (1) comprising the following steps:

providing a plasma spraying device (1), including a plasma torch (4), with a nozzle body (7), said plasma torch (4) having an aperture (9) running along a central longitudinal axis (10) through said nozzle body (7), and the aperture (9) having an convergent section (11) with an inlet (12) for the plasma gas (5), a throat section (13) including a minimum cross-sectional area of the aperture (9), and a divergent section (14) with an outlet (15) for the plasma gas (5), wherein an introducing duct (16) is provided for introducing a liquid precursor (17) into a plasma gas stream (8);

introducing a plasma gas (5) into the inlet (12) of the convergent section (11) of the aperture (9), and feeding the plasma gas (5) through the convergent section (11), the throat section (13), and the divergent section (14) to the outlet (15) of the divergent section (14);

ignitioning and establishing a plasma flame inside the plasma torch (4) in a heating zone (6), heating up the plasma gas (5) and forming the plasma gas stream (8);

coating a surface of a substrate (3) by feeding the plasma gas stream (9) via the outlet (15) of the diverging section (14) of the aperture (9) onto the surface of the substrate (3);

characterized in that a penetration means (18, 161, 181, 182) is provided and the liquid precursor (17) is penetrated through the introducing duct (16) inside the plasma gas stream (8) with the aid of the penetration means (8, 181).

16. Method in accordance with claim 15, wherein the introducing duct (16) is provided between the convergent section (11) and the divergent section (14) of the aperture (9), in particular at the minimum cross-sectional area of the aperture (9) and/or wherein the introducing duct (16) is provided between the inlet (12) of the convergent section (11) and the minimum cross-sectional area of the aperture (9) and/or wherein the introducing duct (16) is provided between the minimum cross-sectional area of the aperture (9) and the outlet (15) of the divergent section (14).

17. Method in accordance with claim 15, wherein the penetration means (18) is a penetration groove (181), being provided at an inner wall (19) of the nozzle body (7), in particular a circumferential penetration groove (181).

18. Method in accordance with claim 15, wherein the penetration groove (181) is provided between the convergent section (11) and the divergent section (14) of the aperture (9), in particular at the minimum cross-sectional area of the aperture (9) and/or wherein the penetration groove (181) is provided between the inlet (12) of the convergent section (11) and the minimum cross-sectional area of the aperture (9) and/or or wherein the penetration groove (181) is provided between the minimum cross-sectional area of the aperture (9) and the outlet (15) of the divergent section (14).

19. Method in accordance with claim 15, wherein the penetration grove (181) has a triangular shape and/or has a width (1811) of 0.5 mm to 3 mm, in particular between 1 mm and 2 mm, especially 1.5 mm and/or has a depth (1812) of 0.05 mm to 2 mm, in particular between 1 mm and 1.5 mm.

20. Method in accordance with claim 15, wherein the penetration means (18) is provided by the introducing duct (16) being designed as a nebulizer (161).

21. Method in accordance with claim 15, wherein the nebulizer (161) is provided between the convergent section (11) and the divergent section (14) of the aperture (9), in particular at the minimum cross-sectional area of the aperture (9) and/or wherein the nebulizer (161) is provided between the inlet (12) of the convergent section (11) and the minimum cross-sectional area of the aperture (9) and/or wherein the nebulizer (161) is provided between the minimum cross-sectional area of the aperture (9) and the outlet (15) of the divergent section (14).

22. Method in accordance with claim 15, wherein the penetration means (18) is provided by the introducing duct (16) being designed as a capillary (182) having an injection hole (183) with reduced diameter.

23. Method in accordance with claim 15, wherein the capillary (182) is provided between the convergent section (11) and the divergent section (14) of the aperture (9), in particular at the minimum cross-sectional area of the aperture (9) and/or wherein the capillary (182) is provided between the inlet (12) of the convergent section (11) and the minimum cross-sectional area of the aperture (9) and/or wherein the capillary (182) is provided between the minimum cross-sectional area of the aperture (9) and the outlet (15) of the divergent section (14).

24. Method in accordance with claim 15, wherein the liquid precursor (17) is introduced at an introducing angle (α

) between 20° and

150°

, in particular between 45° and

135°

, preferably between 70° and

110°

, especially about 90°

.

25. Method in accordance with claim 15, wherein the liquid precursor (17) is a slurry, and/or a suspension, and/or the fluid is water, and/or an acid, and/or an alkali fluid, and/or an organic fluid, in particular methanol, and/or an salt solution and/or an , and/or another coating fluid, and/or the liquid precursor (17) is a suspension or a slurry, in particular a liquid precursor comprising nanoparticles and/or an solution or mixing of the aforementioned liquid precursor (17).