Polycrystalline Diamond Cutting Element

Abstract

A polycrystalline-diamond cutting element for a drill bit of a downhole tool. The cutting element includes a substrate and a diamond table bonded to the substrate. The diamond table includes a diamond filler with at least one leached polycrystalline diamond segment packed therein along at least one working surface thereof. The cutting element may be formed by positioning the diamond table on the substrate and bonding the diamond table onto the substrate such that the polycrystalline diamond segment is positioned along at least one working surface of the diamond table. A spark plasma sintering or double press operation may be used to bond the diamond table onto the substrate.

What is claimed is: 
     
         1 . A polycrystalline-diamond cutting element for a drill bit of a downhole tool, comprising:
 a substrate; and   a diamond table bonded to the substrate, the diamond table comprising a polycrystalline diamond material intermixed with small polycrystalline diamond particles that are substantially free of all catalyzing and other metallic material along at least one working surface thereof;   wherein the small polycrystalline diamond particles comprise small particles formed from a polycrystalline diamond blank with a metallic catalyst therein that has been subjected to a first high temperature-high pressure pressing operation, leached of substantially all of the other metallic materials, and intermixed with the polycrystalline diamond material; and   wherein the diamond table is subjected to a second high temperature-high pressure pressing operation.   
     
     
         2 . The polycrystalline diamond cutting element of  claim 1 , wherein the small polycrystalline diamond particles are formed by sintering and crushing the polycrystalline blank and sizing the crushed polycrystalline blank into the small particles. 
     
     
         3 . Polycrystalline diamond cutting element of  claim 2 , wherein the polycrystalline diamond cutting element has a higher wear resistance than a polycrystalline diamond cutting element comprising a diamond table comprising no material that has been sintered prior to formation of the diamond table. 
     
     
         4 . The polycrystalline diamond cutting element of  claim 1 , wherein the small polycrystalline diamond particles are leached particles that have been leached before the small particles are formed from the polycrystalline diamond blank. 
     
     
         5 . The polycrystalline diamond cutting element of  claim 1 , wherein the small particles are leached after they are formed from the polycrystalline diamond blank. 
     
     
         6 . The polycrystalline diamond cutting element of  claim 1 , wherein the small particles have selected sizes and shapes. 
     
     
         7 . The polycrystalline diamond cutting element of  claim 1 , wherein the substrate comprises tungsten carbide, cobalt, nickel-nano-tungsten carbide and combinations thereof. 
     
     
         8 . The polycrystalline diamond cutting element of  claim 1 , wherein the diamond material comprises diamond feedstock, diamond powder and combinations thereof. 
     
     
         9 . The polycrystalline diamond cutting element of  claim 1 , wherein the plurality of small leached polycrystalline diamond particles are positioned along at least one of a top and peripheral working surface. 
     
     
         10 . The polycrystalline diamond cutting element of  claim 1 , wherein the first high temperature-high pressure pressing operations have a temperature higher than 1300° C. and a pressure greater than 65 KBar. 
     
     
         11 . The polycrystalline diamond cutting element of  claim 1 , wherein the first high temperature-high pressure pressing operations have a temperature higher than 1300° C. and a pressure greater than 65 KBar. 
     
     
         12 . The polycrystalline diamond cutting element of  claim 1 , wherein the second high temperature-high pressure pressing operations have a temperature higher than 1300° C. and a pressure greater than 65 KBar. 
     
     
         13 . The polycrystalline diamond cutting element of  claim 1 , further comprising a carrier, the substrate bonded to the carrier. 
     
     
         14 . The polycrystalline diamond cutting element of  claim 1 , wherein the small polycrystalline diamond particles comprise small particles of less than about 5 micron in size. 
     
     
         15 . The polycrystalline diamond cutting element of  claim 1 , wherein the small polycrystalline diamond particles are leached small polycrystalline diamond particles substantially free of all catalyzing and other metallic material due to leaching. 
     
     
         16 . The polycrystalline diamond cutting element of  claim 1 , wherein the at least one working surface comprises a top working surface, a peripheral working surface, or both a top working surface and a peripheral working surface of the diamond table. 
     
     
         17 . The polycrystalline diamond cutting element of  claim 1 , wherein the at least one working surface is a leached surface, as a result of treating all or a portion of the at least one working surface in a leaching process to remove all or select portions of any catalyst that may have infiltrated during the bonding of the diamond table onto the substrate. 
     
     
         18 . The polycrystalline diamond cutting element of  claim 1 , wherein the small, polycrystalline diamond particles comprise a grit, and wherein the size, quantity, and/or layer thickness of the grit are selected such that the polycrystalline diamond cutting element is self-sharpening. 
     
     
         19 . The polycrystalline diamond cutting element of  claim 18 , wherein the small polycrystalline diamond particles comprise small particles of about 0.5 micron in size. 
     
     
         20 . The polycrystalline diamond cutting element of  claim 1 , wherein the first high temperature-high pressure pressing operation and the second high temperature-high pressure pressing operation comprise the same conditions.