Superabrasive articles and methods for removing interstitial materials from superabrasive materials
View Patent ↗A method of processing a polycrystalline diamond material is disclosed. According to the method, a metal-solvent catalyst is leached from a polycrystalline diamond material by exposing at least a portion of the polycrystalline diamond material to a leaching solution. The leaching solution includes water, a complexing agent, and a mineral acid. The complexing agent is configured to inhibit tungsten in the polycrystalline diamond material from oxidizing.
1. A method of processing a polycrystalline diamond material, the method comprising:
leaching a metal-solvent catalyst from a polycrystalline diamond material by exposing at least a portion of the polycrystalline diamond material to a leaching solution, the leaching solution comprising:
water;
a complexing agent at a molar concentration of between approximately 0.01 M and approximately 3 M;
a mineral acid at a molar concentration of between approximately 0.1 M and approximately 3 M.
2. The method of claim 1 , wherein the complexing agent comprises a chelating agent.
3. The method of claim 1 , wherein the complexing agent comprises a phosphate.
4. The method of claim 1 , wherein the complexing agent comprises a weak acid having an acid dissociation constant (pK a ) of between approximately −2 and 12.
5. The method of claim 1 , wherein the complexing agent comprises at least one of:
phosphoric acid;
citric acid;
tartaric acid;
oxalic acid;
ammonium chloride.
6. The method of claim 1 , wherein the leaching solution comprises the complexing agent at a molar concentration of approximately 0.125 M.
7. The method of claim 1 , wherein the metal-solvent catalyst comprises at least one of:
cobalt;
nickel;
iron.
8. The method of claim 1 , wherein the mineral acid comprises at least one of:
nitric acid;
hydrochloric acid;
sulfuric acid;
boric acid;
hydrofluoric acid.
9. The method of claim 1 , wherein the leaching solution comprises the mineral acid at a molar concentration of approximately 1.5 M.
10. The method of claim 1 , wherein the leaching solution further comprises a peroxide.
11. The method of claim 1 , wherein the complexing agent forms metal complexes with the tungsten.
12. The method of claim 11 , wherein the metal complexes are soluble in the leaching solution.
13. The method of claim 11 , wherein each of the metal complexes comprises:
a tungsten atom:
between 2 and 4 ligands.
14. The method of claim 1 , wherein:
the polycrystalline diamond material comprises bonded diamond grains;
at least a portion of the tungsten and at least a portion of the metal-solvent catalyst are disposed between the bonded diamond grains.
15. The method of claim 1 , further comprising exposing at least a portion of the polycrystalline diamond material and the leaching solution to a temperature of between approximately 25° C. and approximately 280° C.
16. The method of claim 1 , further comprising exposing at least a portion of the polycrystalline diamond material and the leaching solution to a pressure of between approximately 20 bar and approximately 100 bar.
17. The method of claim 1 , further comprising exposing at least a portion of the polycrystalline diamond material and the leaching solution to at least one of:
an electric current;
microwave radiation;
ultrasonic energy.
18. The method of claim 1 , further comprising separating the polycrystalline diamond material from the leaching solution when the polycrystalline diamond material is substantially free of the metal-solvent catalyst to a depth of between approximately 100 μm and approximately 2500 μm.
19. A method of processing a superabrasive element, the method comprising:
providing a superabrasive element comprising:
a substrate;
a polycrystalline diamond table bonded to the substrate, the polycrystalline diamond table comprising tungsten and a metal-solvent catalyst;
leaching at least a portion of the metal-solvent catalyst from the polycrystalline diamond table by exposing at least a portion of the polycrystalline diamond table to a leaching solution, the leaching solution comprising:
water;
a complexing agent at a molar concentration of between approximately 0.01 M and approximately 3 M;
a mineral acid at a molar concentration of between approximately 0.1 M and approximately 3 M.
20. A method of processing a polycrystalline diamond material, the method comprising:
providing a polycrystalline diamond material, the polycrystalline diamond material comprising:
bonded diamond grains;
tungsten;
a metal-solvent catalyst;
providing a leaching solution to the polycrystalline diamond material, the leaching solution comprising:
water;
a complexing agent at a molar concentration of between approximately 0.01 M and approximately 3 M;
a mineral acid at a molar concentration of between approximately 0.1 M and approximately 3 M;
forming metal complexes within the polycrystalline diamond material, the metal complexes comprising:
at least a portion of the tungsten;
at least a portion of the complexing agent;
dissolving at least a portion of the metal-solvent catalyst in the leaching solution;
extracting the dissolved metal-solvent catalyst from the polycrystalline diamond material.