US4200669A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Laser spraying
Assignee: United States Department of the Navy
•
Filing: 1978-11-22
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Granted: 1980-04-29
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Expires: 1998-11-22
Abstract
Abstract A method and apparatus for spraying a surface which comprises: introducing into a laser beam, a powder with a vapor pressure from 10 -2 to 10 -1 atm. in excess of the ambient pressure at a temperature up to about 500° C. above the melting point thereof and with a heat-absorption coefficient from 0.2 to 1; and passing the laser beam over said surface. Since the method and apparatus can coat or alloy or dope a surface, a wide variety of protective coatings can be fabricated.
Inventors
- 👤 Robert J. Schaefer
- 👤 Jack D. Ayers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 23:53
CPC Classifications
B; B05; B05B; B05B7/00; B05B7/16; B05B7/22; B05B7/228; C; C23; C23C; C23C4/00; C23C4/12; C23C4/137
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
94 words
A method of spraying a surface which comprises: selecting a powder with a vapor pressure from 10 -2 to 10 -1 atmosphere in excess of the ambient pressure at a temperature up to about 500° C. above the melting point thereof and with a heat absorption coefficient from 0.2 to 1.0; introducing said powder into a laser beam with a wavelength smaller than the diameter of said powder and a power density of at least one kW/cm 2 at the point of entry; and directing said laser beam on the surface to be sprayed.
Claim 2
Independent Claim
94 words
A method of spraying a surface which comprises: selecting a powder with a vapor pressure from 10 -2 to 10 -1 atmosphere in excess of the ambient pressure at a temperature up to about 500° C. above the melting point thereof and with a heat absorption coefficient from 0.2 to 1.0; introducing said powder into a laser beam with a wavelength smaller than the diameter of said powder and a power density of at least one kW/cm 2 at the point of entry; and directing said laser beam on the surface to be sprayed.
Claim 3
Dependent Claim
49 words
The method of claim 1 wherein the diameter of said powder is about 200 micrometers or less and the vapor pressure of the powder is 10 -2 to 10 -1 atmospheres at a temperature from the melting point to about 500° C. above the melting point of said powder.
Claim 4
Dependent Claim
27 words
The method of claim 1 wherein said powder is introduced in an amount such that the smallest beam area-to-total particle area ratio is not less than 4:1.
Claim 5
Dependent Claim
13 words
The method of claim 3 wherein said ratio is from 7:1 to 10:1.
Claim 6
Dependent Claim
12 words
The method of claim 1 wherein said laser beam is not continuous.
Claim 7
Dependent Claim
24 words
The method of claim 5 wherein the duration of said laser beam is about one tenth of the thermal relaxation time of said powder.
Claim 8
Dependent Claim
20 words
The method of claim 5 wherein the maximum perimeter energy-to-center energy ratio is greater than 1:1 but less than 2.5:1.
Claim 9
Dependent Claim
17 words
The method of claim 7 wherein said maximum perimeter energy-to-center energy ratio is from 1.5:1 to 2.0:1.
Claim 10
Dependent Claim
42 words
The method of claim 4 wherein said laser beam is pulsed, the pulses having a duration of about one tenth of the thermal relaxation time of said powder and the beam having a maximum perimeter energy-to-center energy ratio from 1.5:1 to 2.0:1.
Claim 11
Dependent Claim
54 words
The method of claim 9 wherein the ambient pressure of the process is reduced below atmospheric pressure and the vapor pressure of said powder is 10 -2 to 10 -1 atmospheres greater than the ambient pressure at a temperature from the melting point to about 500° C. above the melting point of said powder.
Claim 12
Dependent Claim
31 words
The method of claim 10 wherein said ambient pressure is from 10 -3 to 10 -1 atmosphere and the average diameter of said powder is from about 40 to 100 microns.
Claim 13
Independent Claim
126 words
A system for modifying a surface by spraying which comprises: a laser for projecting a beam with a power density and wavelength of such magnitude to vaporize powder particles on the side exposed to said laser sufficiently rapidly to propel said particles to said surface at such velocity as is required to effect the intended modification, said powder having a vapor pressure from 10 -2 to 10 -1 atmosphere greater than the ambient pressure at a temperature up to about 500° C. above the melting point thereof; a source of supply for said powder; means for transporting said powder to said laser beam from said supply; and means for introducing said powder into said laser beam from said transporting means at a distance from said surface.
Claim 14
Independent Claim
126 words
A system for modifying a surface by spraying which comprises: a laser for projecting a beam with a power density and wavelength of such magnitude to vaporize powder particles on the side exposed to said laser sufficiently rapidly to propel said particles to said surface at such velocity as is required to effect the intended modification, said powder having a vapor pressure from 10 -2 to 10 -1 atmosphere greater than the ambient pressure at a temperature up to about 500° C. above the melting point thereof; a source of supply for said powder; means for transporting said powder to said laser beam from said supply; and means for introducing said powder into said laser beam from said transporting means at a distance from said surface.
Claim 15
Dependent Claim
25 words
The system of claim 12 which further comprises: a chamber wherein said surface is located; and means for introducing said laser beam into said chamber.
Claim 16
Dependent Claim
24 words
The system of claim 12, wherein: said means for introducing said powder into a beam from said laser further comprises a thermal shielding means.
Claim 17
Dependent Claim
16 words
The system of claim 13 which further comprises means for directing said beam on said surface.
Claim 18
Dependent Claim
29 words
The system of claim 15 wherein said means for introducing said powder into said beam and said means for directing said beam on said surface comprise a single means.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-04-29 | 1983-10-29 | 1984-04-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-04-29 | 1987-10-29 | 1988-04-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-04-29 | 1991-10-29 | 1992-04-29 | $7700.00 | Window Closed / Lapsed |