Thermal spray for durable and large-area hydrophobic and superhydrophobic/icephobic coatings

Patent metadata

Field	Value
Publication number	US-11459481-B2
Application number	US-201414508846-A
Country	US
Kind code	B2
Filing date	Oct 7, 2014
Priority date	Oct 7, 2014
Publication date	Oct 4, 2022
Grant date	Oct 4, 2022

Abstract

A method for forming a hydrophobic coating on a substrate by a thermal spray deposition process is described. The method may comprise feeding a thermal spray apparatus with a coating precursor consisting of particles having an initial particle morphology, and heating the particles with the thermal spray apparatus to cause the particle to at least partially melt. The method may further comprise accelerating the particles towards the substrate, and forming the hydrophobic coating on the substrate by allowing the particles to impact the substrate in a partially melted state in which a fraction of the initial particle morphology of at least some of the particles is retained.

First claim

What is claimed is:

1. A method for forming a polymeric hydrophobic coating on a substrate by a high velocity oxygen fuel (HVOF) thermal spray deposition process, comprising:
feeding a HVOF thermal spray torch with a coating precursor, the coating precursor including polymeric particles of a polymer powder, the polymeric particles having an initial particle morphology;
heating the polymeric particles with the HVOF thermal spray torch;
controlling a heating temperature of the HVOF thermal spray torch to obtain a mixture of partially melted polymeric particles, which retain a fraction of the initial particle morphology, and fully unmelted polymeric particles, which fully retain the initial particle morphology, wherein controlling the heating temperature of the HVOF thermal spray torch comprises tuning at least one deposition parameter of the HVOF thermal spray process, including setting a fuel-to-oxygen ratio of the HVOF thermal spray torch to less than one to prevent complete melting and/or burning of the polymeric particles;
accelerating the polymeric particles towards the substrate using the HVOF thermal spray torch; and
impacting the substrate simultaneously with the partially melted polymeric particles and the fully unmelted polymeric particles to form the polymeric hydrophobic coating with an average surface roughness of between about 1 nanometer and about 100 micrometers.

2. The method of claim 1 , wherein the coating precursor comprises a powder having an average particle size of between about 10 nanometers and about 100 micrometers.

3. The method of claim 1 , wherein tuning the at least one deposition parameter further includes tuning an oxygen feed rate and a fuel feed rate of the HVOF torch.

4. The method of claim 1 , wherein tuning the at least one deposition parameter further includes tuning a stand-off distance between the HVOF thermal spray torch and the substrate.

5. The method of claim 1 , further comprising heating the polymeric hydrophobic coating subsequent to impacting the substrate with the polymeric particles, thereby to increase an oxide content of the polymeric hydrophobic coating.

6. The method of claim 1 , wherein the coating precursor consists of a single component having a single chemical identity with a single particle size and single particle morphology.

7. The method of claim 1 , wherein the coating precursor consists of a primary component and a secondary component having a smaller thermal mass than the primary component, wherein the primary component and the secondary component have the same chemical identity but a different particle size and a different particle morphology, and wherein coating precursor consists of more than 50 weight percent of the primary component.

8. The method of claim 1 , wherein the coating precursor consists of a primary component and a secondary component, wherein the primary component and the secondary component have a different chemical identity and a same particle size and a same particle morphology, and wherein the coating precursor consists of more than 50 weight percent of the primary component.

9. The method of claim 1 , wherein the coating precursor consists of a primary component and a secondary component, wherein the primary component and the secondary component have a different chemical identity and a different particle size and a different particle morphology, and wherein the coating precursor consists of more than 50 weight percent of the primary component.

10. The method of claim 1 , further comprising applying an additional layer on the hydrophobic coating by a HVOF thermal spray deposition process comprising:
feeding the HVOF thermal spray torch with secondary particles having an initial particle morphology, the secondary particles having at least one of a lower surface energy and a smaller particle size than the particles of the coating precursor;
heating the secondary particles with the HVOF thermal spray torch to cause the secondary particles to at least partially melt;
accelerating the secondary particles towards the substrate using the HVOF thermal spray torch; and
forming the additional layer on the hydrophobic coating by allowing the secondary particles to impact the substrate in a partially melted state in which a fraction of the initial particle morphology of at least some of the secondary particles is retained.

11. The method of claim 10 , wherein the additional layer is a monolayer that covers between about 70% and about 150% of a surface of the hydrophobic coating.

12. The method of claim 10 , wherein the secondary particles have a particle size that is at least one order of magnitude smaller than the particles of the coating precursor.

13. The method of claim 10 , wherein the hydrophobic coating includes the additional layer, and wherein the hydrophobic coating exhibits multi-length scale surface roughness.

14. A method of forming a polymeric hydrophobic coating on a substrate by a high velocity oxygen fuel (HVOF) thermal spray deposition process, comprising:
feeding a HVOF thermal spray torch with polymeric particles, the polymeric particles including at least 50 weight percent of polyether ether ketone (PEEK) particles, the polymeric particles having an initial particle morphology;
heating the polymeric particles with the HVOF thermal spray torch;
controlling a heating temperature of the HVOF thermal spray torch to obtain a mixture of partially melted polymeric particles, which retain a fraction of the initial particle morphology, and fully unmelted polymeric particles, which fully retain the initial particle morphology, wherein controlling the heating temperature of the HVOF thermal spray torch comprises adjusting deposition parameters of the HVOF thermal spray deposition process including adjusting a fuel-to-oxygen ratio of the HVOF thermal spray torch to between about 0.5 to about 0.9, adjusting a fuel feed rate of the HVOF thermal spray torch to between about 1.5 to about 2.2 gallons per hour (GPH), and adjusting an oxygen feed rate of the HVOF thermal spray torch to between about 600 to about 900 standard cubic feet per hour (SCFH);
accelerating the polymeric particles toward the substrate using the HVOF thermal spray torch; and
impacting the substrate simultaneously with the partially melted polymeric particles and the fully unmelted polymeric particles to form the polymeric hydrophobic coating with an average surface roughness of between about 1 nanometer and about 100 micrometers, the coating further having a water contact angle of 90° or more.

15. The method of claim 14 , further comprising heating the polymeric hydrophobic coating subsequent to impacting the substrate with the polymeric particles, thereby to increase an oxide content of the polymeric hydrophobic coating.

Assignees

• Boeing Co

Inventors

• Newbloom Gregory M
• Thompson William A
• Froning Marc J
• Ghabchi Arash

Classifications

• B05D1/10 Primary

  Applying particulate materials · CPC title

• C09D127/18

  Homopolymers or copolymers of tetrafluoroethene · CPC title

• C23C4/129

  Flame spraying · CPC title

• B05D5/083

  involving the use of fluoropolymers · CPC title

• C23C4/126

  Detonation spraying · CPC title