Claims
- 1. A carbon-capturing method of promoting wetting of a field-emission, ion-beam, carbon substrate by a boron-based, metal ion source which includes trace impurities of carbon, said method comprising
- applying to such a substrate a binary metal alloy including a predominance of boron,
- heating the substrate-applied alloy to place it in a heated, plural-phase state,
- during said heating, and with the alloy in such a state, capturing trace impurities of carbon in the form of B.sub.4 C and,
- by said capturing and B.sub.4 C forming, creating a condition in the alloy which enhances its ability to spread and wet the substrate.
- 2. A carbon-capturing method of promoting wetting of a field-emission, ion-beam, carbon substrate by a boron-based, metal ion source which includes trace impurities of carbon, said method comprising
- applying to such a substrate a binary metal alloy including a predominance of boron, wherein the alloy takes the form of boron combined with an element selected from the group of elements consisting of nickel, palladium and platinum, and wherein boron makes up about 60-atomic-percent of the alloy,
- heating the substrate-applied alloy to place it in a heated, plural-phase state,
- during the heating, and with the alloy in such a state, capturing trace impurities of carbon in the form of B.sub.4 C and,
- by said capturing and B.sub.4 C forming, creating a condition in the alloy which enhances its ability to spread and wet the substrate.
- 3. In combination with a field-emission, ion-beam, carbon-support substrate, a boron(B)-based liquid-metal ion source comprising a binary alloy with the formulation (X).sub.a (B).sub.b, wherein a equals less than 50-atomic-percent, b equals (100-a)-atomic-percent and X is selected from the group of elements consisting of nickel, palladium and platinum.
- 4. The combination of claim 3, wherein b equals about 60 atomic percent.
- 5. A process for coating a graphite needle surface with a boron alloy for use as an ion-beam emission source comprising
- forming a boron rich binary alloy of boron with another metal selected from the group consisting of nickel palladium and platinum,
- applying said alloy to said graphite needle, and
- heating said graphite needle to a temperature to cause said alloy to wet and spread on said graphite needle while said alloy is in a solid/liquid phase.
- 6. A process for coating a carbon substrate with a boron alloy for use as an ion-beam emission source comprising
- forming a boron-rich binary alloy of boron with another metal selected from the group consisting of nickel, palladium and platinum,
- applying said alloy to said carbon substrate, and
- heating said carbon substrate to a temperature to cause said alloy to wet and spread on said carbon substrate while said alloy is in a liquid/solid phase.
- 7. A method for wetting a graphite substrate surface and spreading a boron alloy over said substrate, comprising the steps of:
- forming a boron rich binary alloy with a metal selected from the group consisting of nickel, palladium and platinum with an atomic percentage of boron in excess of a eutectic composition and effective to precipitate boron in a solid phase at a wetting temperature less than the liquid-phase boundary temperature of said alloy, said excess boron being sufficient to spread and cover an amount of said substrate surface at said wetting temperature;
- applying said alloy to said substrate; and
- heating said graphite substrate to said wetting temperature for a time effective for said alloy to wet and spread over said substrate.
- 8. A method according to claim 7, wherein said metal is platinum and said atomic percentage of boron is greater than 46%.
- 9. A method according to claim 7, wherein said metal is nickel and said atomic percentage of boron is at least about 50%.
- 10. A method according to claim 9, wherein said temperature is at least about 1400.degree.K.
- 11. A method according to claim 7, wherein said metal is palladium and said atomic percentage of boron is at least about 45%.
- 12. A method according to claim 11, wherein said temperature is at least about 1500.degree.K.
- 13. A method for forming an ion-beam emission source with a graphite needle coated with a boron alloy, comprising the steps of:
- forming a boron rich binary alloy with a metal selected from the group consisting of nickel, palladium and platinum with an atomic percentage of boron in excess of a eutectic composition and effective to precipitate boron in a solid phase at a wetting temperature less than the liquid-phase transition temperature of said alloy, said excess boron being sufficient to spread and cover an amount of said needle at said wetting temperature;
- applying said alloy to said needle; and
- heating said graphite needle to a temperature above the melting temperature of said alloy and below said transition temperature for a time effective for said alloy to wet and spread over said needle.
- 14. A method according to claim 13, wherein said metal is platinum and said atomic percentage of boron is greater than 46%.
- 15. A method according to claim 13, wherein said metal is nickel and said atomic percentage of boron is at least about 50%.
- 16. A method according to claim 15, wherein said temperature is at least about 1400.degree.K.
- 17. A method according to claim 13, wherein said metal is palladium and said atomic percentage of boron is at least about 45%.
- 18. A method according to claim 17, wherein said temperature is at least about 1500.degree.K.
Parent Case Info
This is a continuation-in-part of application Ser. No. 08/706,357, filed Aug. 30, 1996, now abandoned, which is a continuation of application Ser. No. 07/053,325, filed May 22, 1987, now abandoned. This is also a continuation-in-part of application Ser. No. 08/692,881, filed Jul. 31, 1996, now abandoned, which is a continuation of application Ser. No. 07/087,932, filed Aug. 21, 1987, now abandoned. Each of the above applications are hereby expressly incorporated by reference.
Government Interests
This invention is the result of a contract with the Department of Energy (Contract No. W-7405-ENG-36).
US Referenced Citations (3)
Non-Patent Literature Citations (8)
Entry |
Buddery et al., "Borides and Silicides of the Platinum Metals" Nature, Mar. 3, 1951, vol. 167, p. 362. |
Hansen, Constitution of Binary Alloys, 1958, Mc Graw-Hill Bool Co. pp. 256-257. |
Jap J. Appl. Phys. 21 277, Apr. 17, 1982 Ishitani. |
Journel De Physique, 47 pp. 95-100 Bozack Mar.-1986. |
Storm, Decleration -Feb. 9, 1988. |
M. J. Bozack et al., "Wettability of Transition Metal Boride Eutectic Alloys to Graphite," J. Mat. Sci. 22, 2421-2430 (1987). |
M. J. Bozack et al., "Materials Considerations In Liquid Metal Ion Source Development," J. de Phys. 47, C2 95-100 (Mar. 1986). |
Tohru Ishitani et al., "Carbon Needle Emitter For Boron And Aluminum Ion Liquid-Metal-Ion Sources," Jpn. J. Appl. Phys. 21, 277-278 (1982). |
Continuations (2)
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53325 |
May 1987 |
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Parent |
87932 |
Aug 1987 |
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Continuation in Parts (1)
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706357 |
Aug 1996 |
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