Polycrystalline diamond materials having improved abrasion resistance, thermal stability and impact resistance

Abstract

PCD materials comprise a diamond body having bonded diamond crystals and interstitial regions disposed among the crystals. The diamond body is formed from diamond grains and a catalyst material at high pressure/high temperature conditions. The diamond grains have an average particle size of about 0.03 mm or greater. At least a portion of the diamond body has a high diamond volume content of greater than about 93 percent by volume. The entire diamond body can comprise high volume content diamond or a region of the diamond body can comprise the high volume content diamond. The diamond body includes a working surface, a first region substantially free of the catalyst material, and a second region that includes the catalyst material. At least a portion of the first region extends from the working surface to depth of from about 0.01 to about 0.1 mm.

What is claimed is: 
     
         1 . A cutting element comprising:
 a polycrystalline diamond body comprising a plurality of bonded diamond crystals and a plurality of interstitial regions disposed among the crystals, the body comprising a first region substantially free of a catalyst material used to sinter the diamond body and a second region that includes the catalyst material, wherein at least a portion of the first region extends from a working surface of the body to a depth of less than about 0.08 mm, and wherein the diamond body includes a diamond content greater than about 93 percent by volume at first location and a diamond content less than about 93 percent at a second location; and   a substrate joined to the diamond body selected from the group consisting of metallic materials, ceramic materials, cermet materials and mixtures thereof.   
     
     
         2 . The cutting element as recited in  claim 1  wherein the first and second locations are within the first region. 
     
     
         3 . The cutting element as recited in  claim 1  wherein the first location is within at least a portion of the first region. 
     
     
         4 . The cutting element as recited in  claim 1  wherein the diamond grains used to form the diamond body have an average particle size of about 0.03 mm or more. 
     
     
         5 . The cutting element as recited in  claim 1  wherein at least a portion of the working surface is a side surface of the diamond body extending from a top surface of the diamond body a partial distance towards the substrate. 
     
     
         6 . The cutting element as recited in  claim 1  where the diamond body is formed from a multimodal distribution of differently sized diamond grains, and wherein a majority of the diamond grains have an average particle size of about 0.05 mm or more. 
     
     
         7 . The cutting element as recited in  claim 1  wherein the first region extends a depth from the working surface of from about 0.01 mm to 0.08 mm. 
     
     
         8 . The cutting element as recited in  claim 1  wherein the first region extends a depth from the working surface of from about 0.02 mm to 0.05 mm. 
     
     
         9 . The cutting element as recited in  claim 1  wherein the diamond body is prepared by subjecting a volume of diamond grains to a high temperature condition to form graphite, and then sintering the volume of diamond grains in the presence of the catalyst material at high-pressure/high-temperature conditions. 
     
     
         10 . The cutting element as recited in  claim 9  wherein the subjecting takes place in a vacuum environment. 
     
     
         11 . A cutting element comprising a polycrystalline diamond body bonded to a metallic substrate, wherein the polycrystalline diamond body is prepared by:
 subjecting a volume of diamond grains to high temperature conditions to form graphite thereon;   subjecting the diamond grains in the presence of a catalyst material to high-pressure/high-temperature conditions to form the diamond body and attach the substrate thereto; and   treating a first region of the polycrystalline diamond body to render it substantially free of the catalyst material while allowing the catalyst material to remain in a second region of the body, wherein the first region extends from a working surface of the body to a depth of less than or equal to about 0.08 mm;   wherein the diamond body comprises a diamond volume content that changes moving from the working surface to an interface with the substrate, and wherein at least a portion of the first region has a diamond content greater than about 93 percent by volume.   
     
     
         12 . The cutting element as recited in  claim 11  wherein a portion of the first region has a diamond content less than about 93 percent by volume, and wherein the first region extends along at least a partial length of a side surface of the diamond from a top surface to the substrate. 
     
     
         13 . The cutting element as recited in  claim 12  wherein the first region extends along a majority of the length of the diamond body side surface. 
     
     
         14 . The cutting element as recited in  claim 11  wherein at least a portion of the second region has a diamond content of from about 85 to 93 percent by volume. 
     
     
         15 . The cutting element as recited in  claim 11  wherein the diamond grains used to form the diamond body have an average particle size of about 0.03 mm. 
     
     
         16 . A bit for drilling subterranean formations comprising a bit body having a number of blades projecting therefrom, and a number of the cutting elements of  claim 11  attached to the blades. 
     
     
         17 . A bit for drilling subterranean formations comprising:
 a body;   a number of cutting elements attached to the body, wherein each of the cutting elements comprise a polycrystalline diamond body of bonded together diamond crystals and interstitial regions between the diamond crystals, the diamond body being attached to a metallic substrate, the polycrystalline diamond body comprising:   a first region comprising interstitial regions that are substantially free of a catalyst material used to sinter the diamond body, the first region being formed from diamond grains having an average particle size of greater than about 0.03 mm, the first region extending from a working surface of the diamond body to a depth of less than about 0.08 mm; and   a second region extending from the first region to the substrate and comprising the catalyst material in the interstitial regions, wherein the diamond body has a diamond content that changes moving from the working surface to the substrate, and wherein at least a portion of the first region has a diamond content that is greater than about 93 percent by volume.   
     
     
         18 . The bit as recited in  claim 17  wherein the first region extends a depth from the working surface from about 0.01 to 0.08 mm, and wherein a portion of the second region has a diamond content that is greater than about 93 percent by volume. 
     
     
         19 . The bit as recited in  claim 17  wherein the polycrystalline diamond body is prepared by subjecting a volume of diamond gains to a high temperature condition to form graphite thereon before sintering the diamond grains at a high-pressure/high-pressure condition. 
     
     
         20 . The bit as recited in  claim 19  wherein the graphite is formed in a vacuum environment.