Diamond enhanced insert with fine and ultrafine microstructure of pcd working surface resisting crack formation

Abstract

An insert for a drill bit may include a metallic carbide body; an outer layer of polycrystalline diamond material on the uppermost end of the insert, wherein the polycrystalline diamond material comprises: a plurality of interconnected diamond grains; a plurality of additive grains; a binder material; wherein the average additive grain size is smaller than the average diamond grain size.

What is claimed is: 
     
         1 . An insert for a drill bit comprising:
 a metallic carbide body;   an outer layer of polycrystalline diamond material on the uppermost end of the insert, wherein the polycrystalline diamond material comprises:
 a plurality of interconnected diamond grains; 
 a plurality of additive grains; 
 a binder material; 
   wherein the average additive grain size is smaller than the average diamond grain size.   
     
     
         2 . The insert of  claim 1 , wherein the average diamond grain size is less than or equal to 4 microns. 
     
     
         3 . The insert of  claim 1 , wherein the average diamond grain size is less than or equal to 2 microns. 
     
     
         4 . The insert of  claim 1 , wherein the average diamond grain size is at least 0.1 microns. 
     
     
         5 . The insert of  claim 1 , wherein the average additive grains size is less than 1 micron. 
     
     
         6 . The insert of  claim 1 , wherein the additive grains are selected from at least one of carbides, carbonitrides, and nitrides. 
     
     
         7 . The insert of  claim 1 , wherein the additive grains comprise greater than 0.5 percent by weight of the polycrystalline diamond material. 
     
     
         8 . The insert of  claim 1 , wherein the additive grains comprise greater than 2 percent by weight of the polycrystalline diamond material. 
     
     
         9 . The insert of  claim 1 , wherein the diamond grains comprise less than 85% by weight of the polycrystalline diamond material. 
     
     
         10 . The insert of  claim 1 , wherein the outer layer has a thickness greater than 250 microns. 
     
     
         11 . The insert of  claim 1 , further comprising at least one transition layer between the metallic carbide body and the outer layer. 
     
     
         12 . The insert of  claim 8 , wherein the at least one transition layer comprises diamond grains having an average grain size larger than the average diamond grain size of the outer layer. 
     
     
         13 . The insert of  claim 1 , wherein the binder material comprises from 15 percent by weight to 30 percent by weight of the outer layer. 
     
     
         14 . The insert of  claim 1 , wherein the binder material comprises cobalt. 
     
     
         15 . A drill bit comprising:
 a bit body;   at least one insert disposed on the drill bit, wherein the insert comprises:
 a metallic carbide body; 
 an outer layer of polycrystalline diamond material on the uppermost end of the insert, wherein the polycrystalline diamond material comprises:
 a plurality of interconnected diamond grains; 
 a plurality of additive grains; 
 a binder material; 
 
 wherein the average additive grain size is smaller than the average diamond grain size. 
   
     
     
         16 . The drill bit of  claim 15 , wherein the average diamond grain size is less than or equal to 4 microns. 
     
     
         17 . The drill bit of  claim 15 , wherein the average diamond grain size is less than or equal to 2 microns. 
     
     
         18 . The drill bit of  claim 15 , wherein the average additive grains size is less than 1 micron. 
     
     
         19 . The drill bit of  claim 15 , wherein the additive grains are selected from at least one of carbides, carbonitrides, and nitrides. 
     
     
         20 . The drill bit of  claim 15 , wherein the additive grains comprise greater than 0.5 percent by weight of the polycrystalline diamond material. 
     
     
         21 . The drill bit of  claim 15 , wherein the diamond grains comprise less than 85% by weight of the polycrystalline diamond material. 
     
     
         22 . The drill bit of  claim 15 , wherein the outer layer has a thickness greater than 250 microns. 
     
     
         23 . The drill bit of  claim 15 , further comprising at least one transition layer between the metallic carbide body and the outer layer. 
     
     
         24 . The drill bit of  claim 23 , wherein the at least one transition layer comprises diamond grains having an average grain size larger than the average diamond grain size of the outer layer. 
     
     
         25 . The drill bit of  claim 15 , wherein the bit body has a plurality of cones mounted thereon, and wherein the at least one insert is inserted into a hole in the one of the plurality of cones. 
     
     
         26 . The insert of  claim 15 , wherein the binder material comprises from 15 percent by weight to 30 percent by weight of the outer layer. 
     
     
         27 . The insert of  claim 15 , wherein the binder material comprises cobalt.