Polycrystalline Material Element with Improved Wear Resistance And Methods of Manufacture Thereof

Abstract

The present invention provides a superhard polycrystalline diamond or diamond-like element with improved wear resistance. Collectively called PCD elements for the purposes of this specification, these elements are formed with a binder-catalyzing material in a high-temperature, high-pressure (HTHP) process. The diamond material is formed and integrally bonded to a substrate containing the catalyzing material during the HTHP process. The diamond body so formed has a working surface, a plurality of crystals being exposed at the working surface, and wherein the exposed crystals are substantially free of microfractures. The exposed parts of the exposed crystals are of rounded or domed form.

What is claimed is:  
     
         1 . A PCD element comprising a body including a matrix of crystals of a superhard material, the body having a surface, a plurality of the crystals of the matrix being exposed at the surface, wherein at least an exposed part of each of the crystals exposed at at least a portion of the surface has a rounded shape as formed.  
     
     
         2 . A PCD element according to  claim 1 , further comprising a substrate to which the body is bonded.  
     
     
         3 . A PCD element according to  claim 1 , wherein the matrix of crystals defines a plurality of interstices, at least some of the interstices containing a binder-catalyst material.  
     
     
         4 . A PCD element according to  claim 3 , wherein the binder-catalyst material comprises a Group VIII material.  
     
     
         5 . A PCD element according to  claim 4 , wherein the binder-catalyst comprises cobalt.  
     
     
         6 . A PCD element according to  claim 1 , wherein the crystals of superhard material comprise diamond crystals.  
     
     
         7 . A PCD element comprising a substrate having a front face, a table of superhard material being bonded to the front face of the substrate, the table of superhard material comprising a matrix of crystals, the table having a surface at which a plurality of the crystals are exposed, at least exposed parts of the crystals exposed at at least a portion of the surface being substantially free of microfractures.  
     
     
         8 . A PCD element according to  claim 7 , wherein the exposed parts of the exposed crystals are of rounded form.  
     
     
         9 . A PCD element according to  claim 7 , wherein the matrix of crystals defines a plurality of interstices, at least some of the interstices containing a binder-catalyst material.  
     
     
         10 . A PCD element according to  claim 9 , wherein the binder-catalyst material comprises a Group VIII material.  
     
     
         11 . A PCD element according to  claim 10 , wherein the binder-catalyst comprises cobalt.  
     
     
         12 . A PCD element according to  claim 7 , wherein the crystals of superhard material comprise diamond crystals.  
     
     
         13 . A method of manufacturing a PCD element comprising: 
 sintering diamond powder with a binder-catalyst material in a high pressure, high temperature press to form a body including a matrix of diamond crystals;    performing a machining operation on the body to form a working surface thereon at which a plurality of diamond crystals are exposed; and    treating the body to render the crystals which are exposed at at least a portion of the working surface substantially free of microfractures.    
     
     
         14 . A method according to  claim 13 , wherein the binder-catalyst material is a Group VIII material.  
     
     
         15 . A method according to  claim 14 , wherein the binder-catalyst material is cobalt.  
     
     
         16 . A method according to  claim 13 , further comprising sintering the diamond powder with a substrate in the high pressure, high temperature press to bond the body to the substrate.  
     
     
         17 . A method according to  claim 16 , wherein the substrate is a tungsten carbide substrate.  
     
     
         18 . A method according to  claim 13 , wherein the step of treating the body includes performing a machining operation on the body in the absence of a coolant material.  
     
     
         19 . A method according to  claim 13 , wherein the step of treating the body includes performing a machining operation on the body with a restricted coolant supply.  
     
     
         20 . A method according to  claim 13 , wherein the step of treating the body includes performing a thermochemical treatment on the body.  
     
     
         21 . A method according to  claim 20 , wherein the thermochemical treatment involves the treatment of the working surface of the body with at least one oxidizing compound.  
     
     
         22 . A method according to  claim 20 , wherein the thermochemical treatment involves the treatment of the working surface of the body with at least one iron group element.  
     
     
         23 . A method according to  claim 13 , wherein a local temperature in excess of 2000° C. is reached at at least a portion of the working surface during the step of treating the body.  
     
     
         24 . A method of manufacturing a PCD element comprising: 
 sintering diamond powder with a binder-catalyst material in a high pressure, high temperature press to form a body including a matrix of diamond crystals;    performing a machining operation on the body to form a working surface thereon at which a plurality of diamond crystals are exposed; and    treating the body to render at least the exposed parts of the crystals exposed at at least a portion of the working surface of rounded form.    
     
     
         25 . A method according to  claim 24 , wherein the binder-catalyst material is a Group VIII material.  
     
     
         26 . A method according to  claim 25 , wherein the binder-catalyst material is cobalt.  
     
     
         27 . A method according to  claim 24 , further comprising sintering the diamond powder with a substrate in the high pressure, high temperature press to bond the body to the substrate.  
     
     
         28 . A method according to  claim 27 , wherein the substrate is a tungsten carbide substrate  
     
     
         29 . A method according to  claim 24 , wherein the step of treating the body includes performing a machining operation on the body in the absence of a coolant material.  
     
     
         30 . A method according to  claim 24 , wherein the step of treating the body includes performing a machining operation on the body with a restricted coolant supply.  
     
     
         31 . A method according to  claim 24 , wherein the step of treating the body includes performing a thermochemical treatment on the body.  
     
     
         32 . A method according to  claim 31 , wherein the thermochemical treatment involves the treatment of the working surface of the body with at least one oxidizing compound.  
     
     
         33 . A method according to  claim 31 , wherein the thermochemical treatment involves the treatment of the working surface of the body with at least one iron group element.  
     
     
         34 . A method according to  claim 25 , wherein a local temperature in excess of 2000° C. is reached at at least a portion of the working surface during the step of treating the body.  
     
     
         35 . A PCD element according to  claim 1 , comprising a preform cutting element having a facing table and a cutting surface, wherein the cutting element is mounted upon a cutting face of a fixed cutter rotary drill bit.  
     
     
         36 . A PCD element according to  claim 1 , comprising a preform cutting element having a facing table and a cutting surface, wherein the cutting element is mounted upon a body of a rolling cutter drill bit.  
     
     
         37 . A PCD element according to  claim 1 , comprising a cutting element with a cutting surface adapted for use as a cutting insert in a machining operation.  
     
     
         38 . A PCD element according to  claim 1 , comprising a drawing die.