Method of treating and coating substrates

• US 5,620,754 A
• Filed: 01/21/1994
• Issued: 04/15/1997
• Est. Priority Date: 01/21/1994
• Status: Expired due to Fees

• Current Assignee: QQC, Inc.
• Original Assignee: QQC, Inc.
• Inventors: Turchan, Manuel C., Mistry, Pravin
• Primary Examiner(s): King, Roy V.
• Application Number:
  US08/184,041
• Time in Patent Office: 1,180 Days
• Field of Search: 427/249, 427/255.4, 427/553, 427/554, 427/555, 427/556, 427/595, 427/596, 427/597, 148/241, 148/278, 148/512, 148/525, 148/565, 219/121.85, 423/446
• US Class Current: 427/554
• CPC Class Codes: B05D 3/06 by exposure to radiation B05D3/02 takes precedence ; plasma treatment B05D3/141
• CPC Class Codes: C23C 14/22 characterised by the process of coating
• CPC Class Codes: C23C 14/28 by wave energy or particle radiation C23C14/32 - C23C14/48 take precedence
• CPC Class Codes: C23C 16/26 Deposition of carbon only
• CPC Class Codes: C23C 16/27 Diamond only
• CPC Class Codes: C30B 25/105 by irradiation or electric discharge
• CPC Class Codes: C30B 29/04 Diamond

Abstract

Energy, such as from one or more lasers, is directed at the surface of a substrate to mobilize and vaporize a constituent element (e.g., carbide) within the substrate (e.g., steel). The vaporized constituent element is reacted by the energy to alter its physical structure (e.g., from carbon to diamond) to that of a composite material which is diffused back into the substrate as a composite material. An additional secondary element, which can be the same as or different from the constituent element, may optionally be directed (e.g., sprayed) onto the substrate to augment, enhance and/or modify the formation of the composite material, as well as to supply sufficient or additional material for fabricating one or more coatings on the surface of the substrate. The process can be carried out in an ambient environment (e.g., without a vacuum), and without pre-heating or post-cooling of the substrate.

Claims

1. Method of treating a substrate, comprising:

directing laser energy at a surface of the substrate, said substrate comprising a plurality of constituent elements, each constituent element of the substrate having an initial physical structure, and with the laser energy;

causing selected amounts of one or more of the constituent elements to move from within the substrate towards the surface of the substrate, thereby producing an increased concentration of the one or more constituent elements in a sub-surface region of the substrate immediately below the surface of the substrate;

vaporizing selected amounts of the one or more constituent elements from the sub-surface region; and

modifying the physical structure of the vaporized one or more constituent elements.

2. Method, according to claim 1, further comprising:

diffusing the modified one or more constituent elements back into the sub-surface region of the substrate, thereby creating a primary conversion zone in the sub-surface region.

3. Method according to claim 2, further comprising:

by controlling the laser energy, providing a desired concentration of the modified one or more constituent elements in the primary conversion zone.

4. Method, according claim 2, further comprising:

after the diffusing step, further directing the laser energy at the substrate to vaporize and further modify the physical structure of the diffused one or more constituent elements within the primary conversion zone.

5. Method, according to claim 4, further comprising:

further directing laser energy at the substrate to achieve a selected concentration or gradient of the diffused one or more constituent elements in the sub-surface region.

6. Method, according to claim 2, further comprising:

further directing laser energy at the surface of the substrate to vaporize and modify the physical structure of additional amounts of the one or more constituent elements from the substrate.

7. Method, according to claim 2, further comprising:

further directing laser energy at the surface of the substrate to vaporize and modify the diffused one or more constituent elements within the primary conversion zone and to vaporize and modify the physical structure of additional amounts of the constituent elements from the substrate.

8. Method, according to claim 2, further comprising:

fabricating, with the laser energy, a coating on the surface of the substrate.

9. Method, according to claim 2, further comprising:

while modifying the physical structure of the vaporized one or more constituent elements, directing a stream of one or more secondary elements at the substrate; and

further directing laser energy at the substrate to fabricate a synthesized coating composition on the surface of the substrate, the synthesized coating being a fabricated structure of the one or more secondary elements and the modified one or more constituent elements.

10. Method, according to claim 9;

wherein;

the modified one or more constituent elements and the one or more secondary elements are the same as one another.

11. Method, according to claim 10, wherein:

the modified one or more constituent elements and the one or more secondary elements are different than one another.

12. Method, according to claim 2, wherein:

the sub-surface region has a depth "d", and includes a primary conversion zone of depth "d1" and a secondary conversion zone of depth "d2", where d1+d2=d; and

the secondary conversion zone is shallower than the primary conversion zone (d2<

d1) and has a higher concentration of the secondary element than the primary conversion zone.

13. Method, according to claim 11, further comprising:

further directing laser energy at the substrate to fabricate a coating on the surface of the substrate.

14. Method, according to claim 2, further comprising:

further directing laser energy at the substrate to vaporize and react the reacted one or more constituent elements from within the conversion zone to form a secondary conversion zone in the sub-surface region of the substrate.

15. Method, according to claim 14, further comprising:

further directing laser energy at the substrate to fabricate a coating on the surface of the substrate.

16. Method, according to claim 1, wherein:

directing sufficient energy at the substrate to cause a first phase of a constituent element to convert to a second phase of the constituent element.

17. Method, according to claim 16, wherein:

the constituent element is carbon;

the first phase is graphite; and

the second phase is diamond.

18. Method, according to claim 2, further comprising:

directing first one or more secondary elements at the substrate;

further directing laser energy at the substrate to fabricate a first synthesized coating composition on the surface of the substrate, the first synthesized coating being a fabricated structure of the first one or more secondary elements and the reacted one or more constituent elements;

directing second one or more secondary elements at the substrate; and

further directing energy at the substrate to fabricate a second synthesized coating composition on a surface of the first synthesized coating composition, the second synthesized coating being a fabricated structure of the second one or more secondary elements and elements of the first synthesized coating composition.

19. Method, according to claim 1, wherein:

the laser energy is in the form of a beam having a selected cross-section.

20. Method, according to claim 19, further comprising:

scanning the beam in a pattern across the surface of the substrate.

21. Method, according to claim 19, further comprising:

scanning the beam across a sequence of selected areas on the surface of the substrate.

22. Method, according to claim 19, wherein:

the laser energy is provided by at least one laser.

23. Method, according to claim 22, wherein:

the at least one laser includes a first laser, a second laser and a third laser.

24. Method, according to claim 23, wherein:

the first laser is an excimer laser.

25. Method, according to claim 24, wherein:

the excimer laser is pulsed.

26. Method, according to claim 23, wherein:

the second laser is a Nd;

YAG laser.

27. Method, according to claim 23, wherein:

the third laser is a CO₂ laser.

28. Method, according to claim 23, wherein:

the first laser is an excimer laser;

the second laser is a Nd;

YAG laser; and

the third laser is a CO₂ laser.

29. Method, according to claim 1, further comprising:

while modifying the physical structure of the vaporized one or more constituent elements, provided at least one secondary element to the reaction process.

30. Method according to claim 19, wherein:

the at least one secondary element includes a gas.

31. Method according to claim 29, wherein:

the at least one secondary element includes a solid.

32. Method according to claim 29, wherein:

the at least one secondary element includes a liquid.

33. Method, according to claim 29, wherein:

the at least one secondary element is provided by spraying the at least one secondary element at the substrate with a pressurized nozzle.

34. Method, according to claim 33, further comprising:

while spraying the at least one secondary element at the substrate, enveloping the at least one secondary element in a gas sufficient to direct the spraying of the at least one secondary element.

35. Method, according to claim 29, wherein:

the at least one secondary element includes a doping element.

36. Method, according to claim 1, further comprising:

during at least the step of modifying the physical structure of the vaporized one or more constituent elements, electrically biassing the substrate.

37. Method, according to claim 1, further comprising:

during at least the step of vaporizing the one or more constituent elements, directing a shielding gas at the substrate.

38. Method, according to claim 1, further comprising:

during at least the step of vaporizing the one or more constituent elements, disposing the substrate in a vacuum.

39. Method, according to claim 1, wherein:

the substrate is an organic compound.

40. Method, according to claim 1, wherein:

the substrate is a material selected from the group consisting of steel, ceramic, and polymeric materials.

41. A method of fabricating a coating of non-uniform thickness on a substrate, comprising:

directing laser energy at a surface of a substrate, and with the energy;

causing selected amounts of one or more constituent elements to move from within the substrate towards the surface of the substrate;

vaporizing selected amounts of the one or more constituent elements;

modifying the physical structure of the vaporized one or more constituent elements; and

forming a coating on the surface of the substrate from the vaporized one or more constituent elements; and

further comprising;

controlling the energy to impart a non-uniform thickness to the coating.

42. A method of coating selected areas of a substrate, comprising:

directing laser energy at selected areas of a surface of a substrate, and with the energy;

moving selected portions of one or more constituent elements towards the surface of the substrate;

vaporizing selected amounts of the one or more constituent elements;

modifying the physical structure of the vaporized one or more constituent elements; and

forming, from the vaporized and modified one or more constituent elements, a material in the sub-surface zone of the substrate; and

further comprising;

directing the laser energy at the selected areas of the substrate to fabricate a coating on the selected areas of the substrate.