Interface Modification of Polycrystalline Diamond Compact

Abstract

A cutting element and a method of providing the cutting element are provided. The cutting element may include a substrate, a first polycrystalline diamond zone, and a second polycrystalline diamond zone. The first polycrystalline diamond zone may be substantially free of a catalyst material. The second polycrystalline diamond zone rich in the catalyst material may be bonded to the substrate along an interface. The second polycrystalline diamond zone may be bonded to the first polycrystalline diamond zone along an effective transition zone. The effective transition zone may have a plurality of irregular projections toward the first polycrystalline diamond zone and the second polycrystalline diamond zone.

What is claimed is: 
     
         1 . A method, comprising the steps of:
 subjecting a plurality of diamond crystals to a high pressure and high temperature condition in the presence of a catalyst material to form a polycrystalline diamond material; and   exposing a portion of the polycrystalline diamond material to a leaching agent at an elevated temperature for a first period of time and then gradually cooling the leaching agent and the polycrystalline diamond material to room temperature over a second period of time, thereby forming:
 a first polycrystalline diamond zone substantially free of the catalyst material, 
 a second polycrystalline element zone rich in the catalyst material, and 
 an effective transition zone sandwiched between the first and the second zones and having:
 a plurality of inter-grain regions that are substantially free of the catalyst material, 
 a plurality of inter-grain regions that are rich in the catalyst material, and 
 a plurality of irregular projections extending toward the first zone and the second zone a distance that is at least 3 times an average diameter of the grains. 
 
   
     
     
         2 . The method of  claim 1 , wherein the second period of time is greater than 1 hour. 
     
     
         3 . The method of  claim 2 , wherein the second period of time is greater than 2 hours. 
     
     
         4 . The method of  claim 1 , wherein the first period of time is greater than 48 hours. 
     
     
         5 . The method of  claim 1 , wherein the distance is less than or equal to about 5 times a size the average diameter of the grains. 
     
     
         6 . The method of  claim 1 , wherein the distance ranges from about 50 to about 120 microns. 
     
     
         7 . The method of  claim 1 , wherein:
 a substrate is also subjected to the high pressure and high temperature condition, and   the substrate is a source of the catalyst material, and   a polycrystalline diamond compact cutting element is formed.   
     
     
         8 . The method of  claim 7 , wherein the substrate is a cemented carbide substrate. 
     
     
         9 . The method of  claim 1 , wherein the leaching agent is a mixture of acids. 
     
     
         10 . The method of  claim 9 , wherein the elevated temperature is just below a boiling temperature of the acid mixture. 
     
     
         11 . The method of  claim 1 , wherein the catalyst material is selected from the group consisting of cobalt, nickel, and iron. 
     
     
         12 . The method of  claim 1 , further comprising inserting another portion of the polycrystalline diamond material into a protective fixture before exposure to the leaching agent. 
     
     
         13 . A method, comprising the steps of:
 subjecting a plurality of diamond crystals to a high pressure and high temperature condition in the presence of a catalyst material to form a polycrystalline diamond material;   masking a portion of a top surface of the polycrystalline diamond material according to a pattern; and   exposing at least the top surface of the polycrystalline diamond material to a leaching agent for a period of time, thereby forming:
 a first polycrystalline diamond zone substantially free of the catalyst material, 
 a second polycrystalline element zone rich in the catalyst material, and 
 an effective transition zone sandwiched between the first and the second zones and having a profile corresponding to the pattern. 
   
     
     
         14 . The method of  claim 13 , wherein the profile is sinusoidal.