SUPERABRASIVE MATERIAL WITH PROTECTIVE ADHESIVE COATING AND METHOD FOR PRODUCING SAID COATING

• US 20140290145A1
• Filed: 04/17/2013
• Published: 10/02/2014
• Est. Priority Date: 03/27/2013
• Status: Active Grant

• Current Assignee: Hardide PLC
• Original Assignee: Hardide PLC
• Inventors: ZHUK, Yuri, LAKHOTKIN, Yuri
• Granted Patent: US 9,346,148 B2
• Time in Patent Office: Days
• US Class Current: 51/295
• CPC Class Codes: B24D 18/0072 using adhesives for bonding abrasive particles or grinding elements to a support, e.g. by gluing
• CPC Class Codes: B24D 3/06 metallic or mixture of metals with ceramic materials, e.g. hard metals, "cermets", cements
• CPC Class Codes: C04B 35/52 based on carbon, e.g. graphite
• CPC Class Codes: C04B 41/009 characterised by the material treated
• CPC Class Codes: C04B 41/4531 by C.V.D.
• CPC Class Codes: C04B 41/4545 applied as a powdery material
• CPC Class Codes: C04B 41/4556 coating or impregnating with a product reacting with the substrate, e.g. generating a metal coating by surface reduction of a ceramic substrate
• CPC Class Codes: C04B 41/5057 Carbides
• CPC Class Codes: C04B 41/5133 with a composition mainly composed of one or more of the refractory metals
• CPC Class Codes: C04B 41/52 Multiple coating or impregnating multiple coating or impregnating with the same composition or with compositions only differing in the concentration of the constituents, is classified as single coating or impregnation
• CPC Class Codes: C04B 41/522 Multiple coatings, for one of the coatings of which at least one alternative is described
• CPC Class Codes: C04B 41/90 at least one coating being a metal
• CPC Class Codes: C09K 3/1445 the coating consisting exclusively of metals
• CPC Class Codes: C23C 12/02 Diffusion in one step
• CPC Class Codes: C23C 16/0272 Deposition of sub-layers, e.g. to promote the adhesion of the main coating
• CPC Class Codes: C23C 16/14 Deposition of only one other metal element
• CPC Class Codes: C23C 16/30 Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
• CPC Class Codes: C23C 24/085 Coating with metallic material, i.e. metals or metal alloys, optionally comprising hard particles, e.g. oxides, carbides or nitrides
• CPC Class Codes: C23C 28/027 including at least one metal matrix material comprising a mixture of at least two metals or metal phases or metal matrix composites, e.g. metal matrix with embedded inorganic hard particles, CERMET, MMC.
• CPC Class Codes: C23C 28/324 with at least one metal matrix material layer comprising a mixture of at least two metals or metal phases or a metal-matrix material with hard embedded particles, e.g. WC-Me
• CPC Class Codes: C23C 28/341 : with at least one carbide layer
• CPC Class Codes: C23C 28/347 : with layers adapted for cutting tools or wear applications
• CPC Class Codes: C23C 28/36 : including layers graded in composition or physical properties
• CPC Class Codes: C23C 28/42 : characterized by the composition of the alternating layers

Abstract

A coating on mono- or poly-crystalline diamond or diamond-containing material includes a first adhesive layer formed directly on the diamond or diamond-containing material, the first layer including tungsten and tungsten carbide alloyed with fluorine in an amount of 0.001 to 0.12 wt % calculated on the total weight of the first layer. The coating further includes a second protective layer formed on the first layer, the second layer including at least tungsten alloyed with fluorine in an amount of 0.001 to 0.12 wt % calculated on the total weight of the second layer. The adhesive layer provides excellent bond strength to diamond, while the protective layer provides good protection against oxidation and molten metals used for attaching the coated diamonds to tools.

Claims

1. A coating on mono- or poly-crystalline diamond or diamond-containing material, the coating comprising a first adhesive layer formed directly on the diamond or diamond-containing material, the first layer comprising tungsten and tungsten carbide alloyed with fluorine in an amount of 0.001 to 0.12 wt % calculated on the total weight of the first layer;

and a second protective layer formed on the first layer, the second layer comprising at least tungsten alloyed with fluorine in an amount of 0.001 to 0.12 wt % calculated on the total weight of the second layer.

2. The coating as claimed in claim 1, wherein the second layer comprises tungsten and tungsten carbide alloyed with fluorine in an amount of 0.001 to 0.12 wt % calculated on the total weight of the second layer.

3. The coating as claimed in claim 1, wherein the first layer has a finer crystalline structure than the second layer.

4. The coating as claimed in claim 1, wherein carbon in the tungsten carbide of the first layer is derived from the diamond or diamond-containing material on which the first layer is formed.

5. The coating as claimed in claim 1, wherein the second layer is a chemically-deposited layer.

6. The coating as claimed in claim 1, wherein the first layer is a chemically-deposited layer.

7. The coating as claimed in claim 1, wherein the first layer includes at least one of tungsten monocarbide (WC) and tungsten semicarbide (W₂C).

8. The coating as claimed in claim 1, wherein the first layer has a thickness of 0.1 to 4 μ

m.

9. The coating as claimed in claim 1, wherein the first layer consists essentially of metal tungsten (W), tungsten monocarbide (WC) and tungsten subcarbide (W₂C), mixed in a composite layer, all alloyed with fluorine in an amount of 0.001 to 0.12 wt %.

10. The coating as claimed in claim 9, wherein the first layer has a ratio of WC:

W₂C;

W in a range (1-100);

(5-20);

(1-100)

11. The coating as claimed in claim 1, wherein the second layer includes at least one of tungsten monocarbide (WC) and tungsten semicarbide (W₂C).

12. The coating as claimed in claim 1, wherein the second layer includes tungsten carbide nanoparticles dispersed in a matrix of metal tungsten, alloyed with fluorine in an amount of 0.001 to 0.12 wt %.

13. The coating as claimed in claim 1, wherein the second layer is itself formed as a plurality of alternating sublayers of tungsten carbide alloyed with fluorine and tungsten alloyed with fluorine.

14. The coating as claimed in claim 13, wherein the sublayers of tungsten carbide alloyed with fluorine are each less than 4 μ

m in thickness.

15. The coating as claimed in claim 1, wherein the second layer is itself formed as a plurality of alternating sublayers of tungsten alloyed with fluorine, and tungsten carbide nanoparticles dispersed in a matrix of metal tungsten, alloyed with fluorine.

16. The coating as claimed in claim 15, wherein the sublayers of tungsten carbide nanoparticles dispersed in a matrix of metal tungsten are each less than 4 μ

m in thickness.

17. The coating as claimed in claim 13, wherein the sublayers have a respective thickness ratio from 10:

1 to 1;

10.

18. The coating as claimed in claim 1, wherein the second layer has a thickness of 0.5 to 500 μ

m.

19. The coating as claimed in claim 18, wherein the second layer has a thickness of 3 to 50 μ

m.

20. The coating as claimed in claim 1, formed on diamond or diamond-containing material comprising diamond, mono-crystalline diamond, poly-crystalline diamond, diamond-silicon carbide composites or other diamond-containing materials substantially free from metal catalysts and being thermally stable at temperatures up to at least 800°

C.

21. The coating as claimed in claim 1, wherein the diamond or diamond-containing material is substantially completely coated.

22. The coating as claimed in claim 1, wherein the diamond or diamond-containing material is substantially completely coated except for portions where it has been held during coating.

23. The coating as claimed in claim 1, wherein the first and second layers are substantially free from through porosity and/or through cracks.

24. The coating as claimed in claim 1, wherein the first and second layers together consist of 93.88 to 99.95 wt % tungsten.

25. The coating as claimed in claim 1, wherein the first and second layers are free from non-refractory binder materials.

26. The coating as claimed in claim 1, the coating having a hardness from 4.0 to 25 GPa.

27. The coating as claimed in claim 1, the coating having a hardness from 6 to 18 GPa.

28. A superabrasive element comprising mono- or poly-crystalline diamond or diamond-containing material coated with the coating of claim 1.

29. A cutting or drilling tool incorporating at least one superabrasive element as claimed in claim 28.

30. A method for producing a cutting or drilling tool, comprising:

coating a mono- or poly-crystalline diamond or diamond-containing material with a coating comprising a first adhesive layer formed directly on the diamond or diamond-containing material, the first layer comprising tungsten and tungsten carbide alloyed with fluorine in an amount of 0.001 to 0.12 wt % calculated on the total weight of the first layer; and

a second protective layer formed on the first layer, the second layer comprising at least tungsten alloyed with fluorine in an amount of 0.001 to 0.12 wt % calculated on the total weight of the second layer;

attaching a superabrasive element to a tool substrate by wetting the second, protective layer of the coating with molten metal.

31. The method according to claim 30, wherein the metal is selected from the group comprising:

cobalt, nickel, iron, copper, titanium, silver, gold, aluminium, indium and alloys containing at least two of these metals.

32. The method according to claim 30, wherein the molten metal is applied by way of infiltration, casting, brazing, spraying, welding, soldering, Hot Isostatic Pressing (HIP) or High Temperature High Pressure (HTHP) cycling.

33. A method of applying a coating to a substrate comprising mono- or poly-crystalline diamond or diamond-containing material, the method comprising:

forming a first adhesive layer directly on the substrate by a first stage chemical deposition process, the first layer comprising tungsten and tungsten carbide alloyed with fluorine in an amount of 0.001 to 0.12 wt % calculated on the total weight of the first layer; and

forming a second protective layer on the first layer by a second stage chemical deposition process, the second layer comprising at least tungsten alloyed with fluorine in an amount of 0.001 to 0.12 wt % calculated on the total weight of the second layer.

34. The method according to claim 33, wherein the first stage chemical deposition process comprises placing the substrate in a carbon-free solid powder medium comprising metallic tungsten powder and fluorides in an amount of 0.1 to 10 wt %, heating in a vacuum or an inert gas atmosphere, and holding at a temperature of 800 to 1050°

C. for at least 10 minutes to form the first adhesive layer.

35. The method according to claim 33, wherein the first stage chemical deposition process comprises placing the substrate in a gaseous medium comprising WF₆ and hydrogen at a volumetric ratio of tungsten hexafluoride to hydrogen from 0.6 to 0.1, at a temperature of 400 to 600°

C. and a pressure of 0.5 to 20 kPa for at least 2 minutes to produce a layer of tungsten alloyed with fluorine in an amount from 0.001 to 0.12 wt %, with a thickness of at least 0.1 μ

m, followed by heat treatment at a temperature between 800°

C. and 1000°

C. for at least 10 minutes to form the first adhesive layer.

36. The method according to claim 35, wherein the layer of tungsten alloyed with fluorine is applied to a thickness up to 100 μ

m.

37. The method according to claim 33, wherein the second stage chemical deposition process comprises placing the substrate coated with the first adhesive layer in a gaseous medium comprising WF₆, hydrogen and optionally hydrocarbons, at a temperature of 350 to 600°

C. and a partial pressure of 0.1 to 20 kPa for at least 10 minutes to form the second protective layer.

38. The method according to claim 33, wherein at least one of the coatings is deposited by way of vapour phase deposition, the vapour being non-ionized and chemically active during the deposition process, with the substrate being moved during the deposition process so as to obtain complete coating over the entire substrate surface.

39. The method according to claim 33, wherein the substrate comprises diamond or diamond-containing grit or elements.