Granted Patent B2

US 8,124,187 · App. 12/555,440 · Granted Feb 28, 2012

Abstract

Claims (60)

1. A method of forming a porous coating on a substrate comprising:

preparing a binder by mixing together:

metal particles including titanium hydride or cobalt disilicide,

a polymer including polybutene or poly-isobutylene,

a brazing agent, and

methyl cellulose;

applying the binder to the substrate to form a binder layer;

applying a coating material that includes titanium or cobalt to the binder layer to form a coating material layer, the binder layer and the coating material layer being applied to the substrate defining a coated substrate; and

sintering the coated substrate.

2. The method of claim 1 , wherein preparing a binder includes mixing together:

0.25-0.46 wt % titanium hydride;

0.32-0.54 wt % polybutene;

98.5-99.1 wt % brazing agent; and

0.31-0.54 wt % methyl cellulose.

3. The method of claim 1 , wherein preparing a binder includes mixing together:

0.052-0.16 wt % cobalt disilicide;

0.10-0.26 wt % polybutene;

99.2-99.6 wt % brazing agent; and

0.26-0.54 wt % methyl cellulose.

4. The method of claim 1 , wherein applying the binder to the substrate includes spray coating at least a portion of the binder onto the substrate to form the binder layer.

5. The method of claim 4 , wherein applying the coating material to the binder layer includes spreading at least a portion of the coating material onto the binder layer to form the coating material layer.

6. The method of claim 5 , further comprising spray coating a further portion of the binder onto the coating material layer to form a binder cover layer.

7. The method of claim 6 , further comprising spreading a further portion of the coating material onto the binder cover layer to form a second coating material layer.

8. The method of claim 1 , wherein sintering the coated substrate includes holding the coated substrate at a temperature of 2350-2600° F. for at least 3 hours.

9. The method of claim 8 , wherein sintering the coated substrate includes holding the coated substrate at a temperature of 2475-2575° F. for at least 3 hours under vacuum.

10. The method of claim 9 , wherein sintering the coated substrate is performed for 9-11 hours.

11. The method of claim 8 , wherein sintering the coated substrate includes holding the coated substrate at a temperature of 2350-2450° F. under vacuum for at least 3 hours.

12. The method of claim 11 , wherein sintering the coated substrate is performed for 3-5 hours.

13. The method of claim 1 , wherein the brazing agent includes nickel.

14. The method of claim 1 , wherein the coating material includes irregularly shaped titanium hydride particles or irregularly shaped cobalt-chromium-molybdenum particles.

15. The method of claim 14 , further comprising

forming a coating material feedstock comprising regularly shaped titanium hydride particles or regularly shaped cobalt-chromium-molybdenum particles, an aromatic hydrocarbon, a thermoplastic, and a lubricant;

injection molding the coating material feedstock into disks;

granulating the disks into irregularly shaped particles; and

holding the irregularly shaped particles under vacuum at a temperature of 80-100° F.

16. The method of claim 15 , wherein the titanium hydride particles or the cobalt-chromium-molybdenum particles have a particle size less than 50 μm.

17. The method of claim 15 , wherein the aromatic hydrocarbon consists of naphthalene and the thermoplastic consists of polystyrene.

18. The method of claim 15 , wherein the coating material feedstock includes:

45-70 vol. % titanium hydride or cobalt-chromium-molybdenum particles;

28-32 vol. % aromatic hydrocarbon;

5-15 vol. % thermoplastic; and

1-10 vol. % lubricant.

19. The method of claim 15 , further comprising sorting the irregularly shaped particles by size and selecting a group of irregularly shaped particles having a given size prior to holding the irregularly shaped particles under vacuum at a temperature of 80-100° F.

20. The method of claim 15 , further comprising heating the irregularly shaped coating material particles to 300° F. until a preselected amount of the aromatic hydrocarbon, the thermoplastic, or the lubricant has been removed.

21. The method of claim 1 , further comprising:

holding the temperature of the coated substrate at 1850-1950° F. for 0.5-1.5 hours;

holding the temperature of the coated substrate at 1500-1600° F. for 7-9 hours; and

cooling the coated substrate from 1500-1600° F. to 150-350° F. at a rate of 75-325° F./min.

22. The method of claim 1 , further comprising blasting the substrate with abrasives prior to applying the binder to the substrate.

23. The method of claim 1 , further comprising cleaning the substrate in a fluid bath subject to ultrasonic waves.

24. The method of claim 1 , further comprising holding the coated substrate at a temperature of 1,650-2,250° F. under a pressure of 15-25 kilopounds per square inch for 2-5 hours.

25. The method of claim 1 , further comprising:

holding the coated substrate at a temperature of 2,075-2,275° F. under vacuum for 4 hours; and

cooling the coated substrate from 2,075-2,275° F. to 100-200° F. at a rate greater than or equal to 75° F./min.

26. A method of forming a porous coating on a substrate comprising:

forming a binder including metal particles, which include titanium hydride or cobalt disilicide, a polymer including polybutene or poly-isobutylene, a brazing agent, and a thickener including methyl cellulose;

spray coating a first portion of the binder onto the substrate to form an inner binder layer;

spreading a coating material including metal particles including titanium or cobalt onto the inner binder layer to form a coating material layer;

spray coating a second portion of the binder onto the substrate to form a coated substrate;

and holding the coated substrate at 2350-2600° F. for at least 3 hours.

Assignments (12)