Polycrystalline diamond materials formed from coarse-sized diamond grains

Abstract

PCD materials of this invention comprise diamond crystals that are bonded together with a catalyst/binder material. The PCD material is prepared by combining diamond grains with a catalyst/binder material either as a premixture or by infiltration during sintering. The PCD material comprises 15 percent by volume or less diamond grains sized 20 micrometers or less. The diamond grains are pressurized under elevated temperature conditions to form the desired PCD material. PCD materials of this invention can constitute the exclusive material phase of a PCD construction, or can form one or more material phase in a multi-phase material microstructure, wherein the multiple material phase can be arranged in an ordered/oriented or random fashion. PCD materials of this invention display improved properties of impact and fatigue resistance, and functional toughness, when used in complex wear environments, when compared to conventional PCs materials comprising intentionally added fine-sized diamond grains.

1 . A polycrystalline diamond material prepared by pressurizing under elevated temperature conditions diamond grains and a binder to form a polycrystalline diamond material comprising 15 percent by volume or less diamond grains having a grain size of 20 micrometers or less based on the total volume of the material.  
   
   
       2 . The polycrystalline diamond material as recited in  claim 1  comprising 10 percent by volume or less diamond grains having a grain size of 20 micrometers or less based on the total volume of the material.  
   
   
       3 . The polycrystalline diamond material as recited in  claim 1  comprising 5 percent by volume or less diamond grains having a grain size of 20 micrometers or less based on the total volume of the material.  
   
   
       4 . The polycrystalline diamond material as recited in  claim 1  wherein diamond grains used to prepare the polycrystalline material comprises 15 percent by volume or less diamond grains having a grain size of 20 micrometers or less based on the total volume of the diamond grains and binder material.  
   
   
       5 . The polycrystalline diamond material as recited in  claim 1  further comprising the step of processing the diamond grains prior to pressurizing, wherein during the step of processing the volume percent of diamond grains sized 20 micrometers or less is increased from that of the diamond grains used to prepare the material.  
   
   
       6 . The polycrystalline diamond material as recited in  claim 1  wherein the binder material is selected from the group consisting of Co, Ni, Fe, and mixtures thereof, and wherein the diamond grains are present in the range of from about 50 to 95 percent by volume of the total mixture.  
   
   
       7 . The polycrystalline diamond material as recited in  claim 1  wherein a majority of the diamond grains have a grain size in the range of from about 35 to 60 micrometers.  
   
   
       8 . A rotary cone rock bit comprising a bit body including at least one journal pin extending from a leg portion of the bit, a cutter cone rotatably mounted on the journal pin, and an insert disposed along a surface of the cutter cone, the insert comprising a polycrystalline diamond construction including the polycrystalline diamond material as recited in  claim 1  disposed along a working surface of the insert.  
   
   
       9 . A polycrystalline diamond material that is prepared by: 
 processing diamond grain starting materials into a desired green part, the diamond grain starting materials having a volume percent of diamond grains sized 20 micrometers and less that is less than that of the diamond grains in the processed green part; and    pressurizing under elevated temperature conditions the green part to form the polycrystalline diamond material, wherein the polycrystalline diamond material comprises greater than about 85 percent by volume diamond grains sized greater than 20 micrometers.    
   
   
       10 . The polycrystalline diamond material as recited in  claim 9  wherein the diamond grain starting material comprises less than 10 percent by volume diamond grains sized 20 micrometers or less based on the total volume of the starting diamond grains.  
   
   
       11 . The polycrystalline diamond material as recited in  claim 9  comprising greater than 90 percent by volume diamond grains having a grain size of greater than 20 micrometers based on the total volume of the material.  
   
   
       12 . An earth-boring drill bit comprising a number of drill bit inserts attached thereto, the drill bit inserts comprising a polycrystalline diamond material disposed along an insert working surface, the polycrystalline diamond material comprising greater than 85 percent by volume diamond grains sized greater than 20 micrometers based on the total volume of the material.  
   
   
       13 . The drill bit as recited in  claim 12 , wherein the polycrystalline diamond material is prepared by: 
 processing diamond grains into a desired green part, wherein during the processing step the volume percent of diamond grains sized 20 micrometers or less is increased; and    pressurizing under elevated temperature conditions the green part to form the polycrystalline diamond material.    
   
   
       14 . The drill bit as recited in  claim 13  wherein the diamond grains used to form the green part comprises before processing less than about 10 percent by volume diamond grains sized 20 micrometers or less based on the total volume of the diamond grains.  
   
   
       15 . The drill bit as recited in  claim 13  wherein a major volume of the diamond grains used to form the green part is sized in the range of from 35 to 55 micrometers.  
   
   
       16 . The drill bit as recited in  claim 12  wherein the polycrystalline diamond material comprises greater than 90 percent by volume diamond grains sized greater than 20 micrometers based on the total volume of the material.  
   
   
       17 . The drill bit as recited in  claim 12  wherein the polycrystalline diamond material comprises up to about 50 percent by volume binder selected from the group consisting of Co, Ni, Fe, and mixtures thereof.  
   
   
       18 . The drill bit as recited in  claim 12  wherein the diamond grains in the polycrystalline diamond material are present in the range of from about 50 to 95 percent by volume based on the total volume of the material, and wherein the diamond grains comprise 10 percent by volume or less diamond grains sized 20 micrometer or less based on the total weight of the material.  
   
   
       19 . The drill bit as recited in  claim 12  wherein the polycrystalline diamond material comprises a random arrangement of multiple material phases.  
   
   
       20 . The drill bit as recited in  claim 12  further comprising: 
 a bit body including at least one journal pin extending from a leg portion of the bit; and    a cutter cone rotatably mounted on the journal pin;    wherein the drill bit inserts are disposed along a surface of the cutter cone.