Method of processing polycrystalline diamond material

Abstract

A method of processing a polycrystalline diamond (PCD) material having a non-diamond phase comprising a diamond catalyst/solvent material comprises leaching an amount of the diamond catalyst/solvent from the PCD material by exposing at least a portion of the PCD material to a leaching mixture. The leaching mixture comprises hydrochloric acid and one or more additional mineral acids, the molar concentration of the hydrochloric acid being greater than the molar concentration of the one or more additional mineral acids in the leaching mixture.

1 . A method of processing a polycrystalline diamond (PCD) material having a non-diamond phase comprising a diamond catalyst/solvent material, the method comprising leaching an amount of the diamond catalyst/solvent from the PCD material by exposing at least a portion of the PCD material to a leaching mixture, the leaching mixture comprising hydrochloric acid and one or more additional mineral acids, the molar concentration of the hydrochloric acid being greater than the molar concentration of the one or more additional mineral acids in the leaching mixture. 
     
     
         2 . The method of  claim 1 , wherein the step of exposing the PCD to a leaching mixture comprises exposing the PCD to the leaching mixture wherein the one or more additional mineral acids comprise one or more of sulphuric acid, phosphoric acid, perchloric acid, or nitric acid. 
     
     
         3 . The method of  claim 1 , wherein the leaching solution comprises hydrochloric acid at a molar concentration of around 3M or greater. 
     
     
         4 . The method of  claim 1 , wherein the leaching mixture comprises a combination of two or more mineral acids in addition to hydrochloric acid, the molar concentrations of the two or more additional mineral acids being substantially identical. 
     
     
         5 . The method of  claim 1 , further comprising heating the leaching mixture to a temperature equal to or greater than the boiling temperature of the leaching mixture during the step of exposing the PCD material to the leaching mixture. 
     
     
         6 . The method of  claim 1 , wherein the metal-solvent catalyst comprises at least one of: cobalt; nickel; iron. 
     
     
         7 . The method according to  claim 1 , wherein the PCD table has a thickness of from about 1.5 mm to about 3.0 mm. 
     
     
         8 . The method of  claim 1 , wherein the step of leaching comprises leaching one or more of a carbide of tungsten, titanium, niobium, tantalum, zirconium, molybdenum, chromium, or vanadium from the PCD material. 
     
     
         9 . The method of  claim 1 , wherein for an average diamond grain size of around 10 microns, the rate of leaching by the acid leaching mixture is around 10 microns per hour. 
     
     
         10 . (canceled)