NANOSTRUCTURED FEEDS FOR THERMAL SPRAY SYSTEMS, METHOD OF MANUFACTURE, AND COATINGS FORMED THEREFROM

• US 20030077398A1
• Filed: 05/20/1999
• Published: 04/24/2003
• Est. Priority Date: 11/13/1995
• Status: Active Grant

• Current Assignee: Bernard H. Kear, Peter R. Strutt, Ross F. Boland
• Original Assignee: Bernard H. Kear, Peter R. Strutt, Ross F. Boland
• Inventors: KEAR, BERNARD H., STRUTT, PETER R., BOLAND, ROSS F.
• Granted Patent: US 6,579,573 B2
• Time in Patent Office: Days
• US Class Current: 427/452
• CPC Class Codes: B01J 13/02 Making microcapsules or microballoons for medical preparations A61K9/50
• CPC Class Codes: C01B 21/0687 After-treatment, e.g. grinding, purification
• CPC Class Codes: C01B 25/32 Phosphates of magnesium, calcium, strontium, or barium
• CPC Class Codes: C01G 25/02 Oxides
• CPC Class Codes: C01G 45/02 Oxides; Hydroxides
• CPC Class Codes: C01P 2002/02 Amorphous compounds
• CPC Class Codes: C01P 2004/03 obtained by SEM
• CPC Class Codes: C01P 2004/10 extending in one dimension, e.g. needle-like
• CPC Class Codes: C01P 2004/32 Spheres
• CPC Class Codes: C01P 2004/50 Agglomerated particles
• CPC Class Codes: C01P 2004/61 Micrometer sized, i.e. from 1-100 micrometer
• CPC Class Codes: C01P 2004/80 Particles consisting of a mixture of two or more inorganic phases
• CPC Class Codes: C04B 35/62222 obtaining ceramic coatings coating of mortars, concrete, artificial or natural stone or ceramics C04B41/45; laminated ceramic products B32B18/00; coating metallic materials C23; coating of glass C03C17/00, applying ceramic coatings on silicon for semi-conductor purposes H01L
• CPC Class Codes: C23C 4/04 characterised by the coating material
• CPC Class Codes: C23C 4/06 Metallic material
• CPC Class Codes: C23C 4/10 Oxides, borides, carbides, nitrides or silicides; Mixtures thereof
• CPC Class Codes: C23C 4/11 Oxides
• CPC Class Codes: C23C 4/123 Spraying molten metal
• CPC Class Codes: Y10S 977/892 Liquid phase deposition

Abstract

This invention relates to methods whereby nanoparticle liquid suspensions are used in conventional thermal spray deposition for the fabrication of high-quality nanostructured coatings. Ultrasound is used for disintegration of the as-synthesized particle agglomerates, nanoparticle dispersion in liquid media, and liquid precursor atomization.

Claims

1. A method for forming a nanostructured coating, comprising

dispersing a nanostructured material in a liquid medium by ultrasound to form a solution having dispersed therein nanostructured particles having particle sizes in the range from 5 to 50 microns;

injecting the solution directly into the feed of a thermal spray apparatus; and

spray coating the solution onto an article to form a nanostructured coating.

2. The method of claim 1, wherein the nanostructured material is selected from the group consisting of ceramics, cermets, and metals.

3. The method of claim 1, wherein the nanostructured material is selected from the group consisting of WC/Co, Cr₃C₂/Ni, Fe₃Mo₃C/Fe, ZrO₂, Al₂O₃, yttria-stabilized zirconia, hydroxyapatite, vitellium, SiC, SiC_xN_y, Si₃N₄, Cr₃C₂/NiCr, and MnO₂.

4. The method of claim 1, wherein the nanostructured material is selected from the group consisting of WC/Co, Cr₃C₂/Ni, ZrO₂, Al₂O₃, SiC, SiC_x, N_y, Cr₃C₂/NiCr, and yttria-stabilized zirconia.

5. The method of claim 1, 2, 3, or 4, wherein the dispersed solution further comprises ceramic whiskers, ceramic hollow shells, cermet whiskers, cermet hollow shells, carbon black, or a combination thereof.

6. The method of claim 1, 2, 3, or 4, wherein the particles size is in the range from 3 to 30 microns.

7. The method of claim 1, wherein an effective amount of superheat above the eutectic point of the nanostructured particles is used during spray coating to form mushy agglomerated particles that will readily flow upon impact with the article being spray coated.

14. The method of claim 1, wherein an effective amount of superheat above the eutectic point of the nanostructured particles is used during spray coating of the first, second, or both solution to form mushy agglomerated particles that will readily flow upon impact with the article being spray coated.

15. The nanostructured coating produced by the method of claim 1.

8. A method for forming nanostructured coating having at least a first and a second layer, comprising

dispersing a first nanostructured material in a liquid medium by ultrasound to form a first solution having dispersed therein nanostructured particles with particle sizes in the range from 5 to 50 microns;

injecting the first solution directly into the feed of a thermal spray apparatus;

spray coating the solution onto an article to form the first nanostructured coating layer; and

dispersing a second nanostructured material in a liquid medium by ultrasound to form a second solution having dispersed therein nanostructured particles with particle sizes in the range from 5 to 50 microns;

injecting the second solution directly into the feed of a thermal spray apparatus; and

spray coating the second solution onto the first layer to form the second nanostructured coating layer.

9. The method of claim 8, wherein the first and second nanostructured materials are the same or different, and are selected from the group consisting of ceramics, cermets, and metals.

10. The method of claim 8, wherein the first and second nanostructured materials are the same or different, and are selected from the group consisting of WC/Co, Cr₃C₂/Ni, Fe₃Mo₃C/Fe, ZrO₂, Al₂O₃, yttria-stabilized zirconia, hydroxyapatite, vitellium, SiC, SiC_xN_y, Si₃N₄, Cr₃C₂/NiCr, and MnO₂.

11. The method of claim 8, wherein the first and second nanostructured materials are the same or different, and are selected from the group consisting of WC/Co, Cr₃C₂/Ni, ZrO₂, Al₂O₃, SiC, SiC_xN_y, Cr₃C₂/NiCr, and yttria-stabilized zirconia.

12. The method of claim 8, 9, 10, or 11, wherein the first, second, or both dispersed solution further comprises ceramic whiskers, ceramic hollow shells, cermet whiskers, cermet hollow shells, carbon black, or a combination thereof.

13. The method of claim 8, 9, 10, or 11, wherein the particle size of the first, second, or both nanostructured material is in the range from 3 to 30 microns.

16. The nanostructured coating formed by the method of claim 8.