Techniques and materials for the accelerated removal of catalyst material from diamond bodies

Abstract

A method for making a thermally stable cutting element may include forming an acid mixture containing two different acid species by combining an acid solution and at least one acid-forming compound, wherein the at least one acid-forming compound is provided in solid form, and wherein the at least one acid-forming compound produces an acid that is different than the acid solution; treating at least a portion of a sintered diamond body by placing the sintered diamond body in the acid mixture, wherein the sintered diamond body comprises: a matrix phase of bonded-together diamond grains; a plurality of interstitial regions dispersed within the matrix phase; and a metal material disposed within a plurality of the interstitial regions; wherein the treating removes the metal material from at least a portion of the plurality of interstitial regions; and removing the sintered diamond body from the acid mixture after a predetermined length of time, wherein at least a portion of the diamond body removed from the acid mixture is substantially free of the metal material and is a thermally stable diamond body.

What is claimed: 
     
         1 . A method for making a thermally stable cutting element comprising:
 treating at least a portion of a sintered diamond body comprising:
 placing a sintered diamond body in an acid mixture of HNO 3  at a concentration of 4.5 to 10 mol/liter and HF at a concentration of 2.5 to 10 mol/liter, the sintered diamond body having:
 a matrix phase of bonded-together diamond grains; 
 a plurality of interstitial regions dispersed within the matrix phase; and 
 a metal material disposed within a plurality of the interstitial regions; 
 
 wherein the treating removes metal material from at least a portion of the plurality of interstitial regions; and 
   removing the sintered diamond body from the acid mixture after a predetermined length of time, wherein the at least a portion of the diamond body removed from the acid mixture is substantially free of the metal material and is a thermally stable diamond body.   
     
     
         2 . The method of  claim 1 , further comprising: forming the acid mixture by combining an HNO 3  solution and at least one HF-forming compound, wherein the at least one HF-forming compound is provided in solid form. 
     
     
         3 . The method of  claim 1 , wherein the treating step further comprises subjecting the sintered diamond body and acid mixture to at least one of elevated temperature conditions, elevated pressure conditions, vibration energy, or ultrasonic energy. 
     
     
         4 . The method of  claim 1 , wherein the sintered diamond body comprises at least about 80 percent by volume diamond. 
     
     
         5 . The method of  claim 1 , wherein the HF-forming compound is a fluoride salt. 
     
     
         6 . The method of  claim 5 , wherein the HF-forming compound is ammonium bifluoride. 
     
     
         7 . The method of  claim 1 , wherein the step of treating further comprises:
 subjecting the acid mixture and sintered diamond body to an elevated temperature; and   reducing the temperature of the acid mixture and sintered diamond body in a controlled manner so as to form soluble salts within the sintered diamond body.   
     
     
         8 . The method of  claim 7 , wherein the soluble salts are disposed within the interstitial regions of the sintered diamond body. 
     
     
         9 . The method of  claim 7 , wherein after the step of removing, further comprising:
 cleaning the thermally stable diamond body to remove the soluble salts and/or insoluble oxides therefrom.   
     
     
         10 . The method of  claim 9 , wherein the step of cleaning comprises placing the thermally stable diamond body into a volume of water that is at an elevated temperature and pressure. 
     
     
         11 . The method of  claim 9 , wherein after the step of cleaning, further comprising:
 reinfiltrating the thermally stable diamond body by filling at least a plurality of the interstitial regions of the thermally stable diamond body with an infiltrant material.   
     
     
         12 . The method of  claim 11 , further comprising:
 a second treating step, wherein the second treating step comprises:   removing the infiltrant material to a desired depth from a surface of the thermally stable diamond body.   
     
     
         13 . The method of  claim 12 , wherein the depth is substantially uniform within the thermally stable diamond body at the center of the thermally stable diamond body compared to a position along a circumferential edge of the thermally stable diamond body. 
     
     
         14 . The method of  claim 1 , wherein the metal material is a catalyst material. 
     
     
         15 . The method of  claim 1 , wherein the metal material is an infiltrant material. 
     
     
         16 . The method of  claim 1 , further comprising:
 cleaning the thermally stable diamond body to remove any residual non-diamond materials remaining therein.   
     
     
         17 . The method of  claim 16 , wherein the step of cleaning comprises subjecting the thermally stable diamond body to at least one process selected from the group consisting of ultrasonic energy, pressurization, electrolysis and gas-phase leaching. 
     
     
         18 . The method of  claim 17 , wherein the step of cleaning comprises subjecting the thermally stable diamond body to ultrasonic in a bath of a solvent. 
     
     
         19 . The method as recited in  claim 17 , wherein during the step of treating, further comprising elevating the pressure conditions of the sintered diamond body and the leaching agent to a desired pressure for a predetermined amount of time. 
     
     
         20 . A method for making a thermally stable cutting element comprising:
 treating at least a portion of a sintered diamond body comprising:
 placing a sintered diamond body in an acid mixture of HNO 3  at a concentration of 2.5 to 10 mol/liter and HF at a concentration of 4.0 to 10 mol/liter, the sintered diamond body having:
 a matrix phase of bonded-together diamond grains; 
 a plurality of interstitial regions dispersed within the matrix phase; and 
 a metal material disposed within a plurality of the interstitial regions; 
 
 wherein the treating removes metal material from at least a portion of the plurality of interstitial regions; and 
   removing the sintered diamond body from the acid mixture after a predetermined length of time, wherein the at least a portion of the diamond body removed from the acid mixture is substantially free of the metal material and is a thermally stable diamond body.