Electrophoretic diamond coating and compositions for effecting same

• US 6,258,237 B1
• Filed: 12/30/1998
• Issued: 07/10/2001
• Est. Priority Date: 12/30/1998
• Status: Expired due to Term

• Current Assignee: Iscar Limited (Berkshire Hathaway Incorporated)
• Original Assignee: CERD Limited, Iscer Limited
• Inventors: Sezin, Nina, Gilboa, Shai, Layyous, Albir A., Brandon, David, Gal-Or, Leah, Goldner, Rony
• Primary Examiner(s): Gorgos, Kathryn
• Assistant Examiner(s): MAISANO, JOSEPHINE R
• Application Number:
  US09/222,934
• Time in Patent Office: 923 Days
• Field of Search: 264/29.1, 428/426, 427/577, 205/104, 205/530, 205/531, 205/471, 205/548, 205/551, 205/489, 205/573, 205/450
• US Class Current: 204/548
• CPC Class Codes: C23C 16/045 Coating cavities or hollow spaces, e.g. interior of tubes; Infiltration of porous substrates
• CPC Class Codes: C23C 16/27 Diamond only
• CPC Class Codes: C23C 16/277 using other elements in the gas phase besides carbon and hydrogen; using other elements besides carbon, hydrogen and oxygen in case of use of combustion torches; using other elements besides carbon, hydrogen and inert gas in case of use of plasma jets
• CPC Class Codes: C23C 16/279 control of diamond crystallography
• CPC Class Codes: C25D 13/02 with inorganic material

Abstract

A method of depositing diamond particles on a surface of a substrate is provided. The method is effected by (a) charging the diamond particles by a positive charge to obtain positively charged diamond particles; and (b) electrophoretically depositing the positively charged diamond particles on the surface of the substrate, for obtaining a green diamond particles coat on the surface of the substrate.

Claims

1. A method of depositing diamond particles on a surface of a cathodic substrate, the method comprising the steps of:

(a) charging the diamond particles by a positive charge by suspending the diamond particles in a polar organic liquid in the presence of cation a generating additive so as to obtain a suspension of positively charged diamond particles; and

(b) from said suspension electrophoretically depositing said positively charged diamond particles on the surface of the cathodic substrate by application of voltage in a range of 50-800 volts for obtaining a green diamond particles coat on the surface of the cathodic subtrate.

2. The method of claim 1, further comprising the step of:

(c) consolidating said green diamond particles coat by a gas-phase deposition method.

3. The method of claim 2, wherein said gas-phase deposition method is selected from the group consisting of chemical vapor deposition (CVD) and an interactive laser technique.

4. The method of claim 3, wherein said chemical vapor deposition (CVD) is selected from the group consisting of plasma CVD, non plasma CVD and a hybrid process of vapor-liquid-solid (VLS) growth.

5. The method of claim 4, wherein said plasma CVD is selected from the group consisting of DC plasma CVD, RF induction plasma CVD and microwave plasma CVD.

6. The method of claim 4, wherein said non plasma CVD is selected from the group consisting of hot filament CVD and laser enhanced CVD.

7. The method of claim 1, further comprising the step of:

(c) consolidating said green diamond particles coat by electroplating or electroless plating.

8. The method of claim 7, wherein said electroplating or electroless plating is by a metal.

9. The method of claim 8, wherein said metal is selected from the group consisting of nickel, copper, gold, silver and cobalt.

10. The method of claim 1, wherein the diamond particles have a size ranging from 0.01 micron to 50 microns.

11. The method of claim 10, wherein the diamond particles have a size selected from the group consisting of 0.5 micron to 1 micron, 1 micron to 4 microns and 4 microns to 12 microns.

12. The method of claim 1, wherein the diamond particles include particles of at least two distinct dimensions.

13. the method of claim 1, wherein said polar organic liquid is selected from the group consisting of ethanol, methanol, isopropanol, methyl ethyl ketone and acetone.

14. The method of claim 13, wherein said proton generating additive is an acidic buffer.

15. The method of claim 13, wherein said proton generating additive is selected from the group consisting of iodine-acetone-water, phosphate ester, polyvinyl butiral and/or acetyl acetone.

16. The method of claim 1, wherein electrophoretically depositing said positively charged diamond particles on the surface of the substrate is effected under constant current.

17. The method of claim 16, wherein said constant current is in a range of 0.1-3.0 milliampere per centimeter squared.

18. The method of claim 1, wherein electrophoretically depositing said positively charged diamond particles on the surface of the substrate is effected under constant voltage.

19. The method of claim 1, wherein said substrate is selected from the group consisting of a metal, a metallic alloy, a semiconductor substrate, a conductive carbide and a metallized non-conductive ceramic material.

20. The method of claim 1, wherein while electrophoretically depositing said positively charged diamond particles on the surface of the substrate, a diamond particles concentration is between 5-200 grams per liter.

21. The method of claim 20, wherein while electrophoretically depositing said positively charged diamond particles on the surface of the substrate, a diamond particles concentration is between 30-120 grams per liter.