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

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.

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.