Patent ID: 7350601

Claim:
A cutting element comprising: an ultra hard body comprising: an uppermost layer comprising a plurality of bonded crystals selected from the group of ultra hard materials consisting of diamond, cubic boron nitride, and mixtures thereof, and a plurality of interstitial regions disposed among the crystals, the uppermost layer including an outer surface that is a working surface of the body, the uppermost layer comprising: an outer region extending from at least a portion of the outer surface to a depth within the uppermost layer, wherein the outer region is substantially free of a catalyst material; and a remaining region that includes the catalyst material; an intermediate layer comprising a plurality of bonded crystals selected from the group of ultra hard materials consisting of diamond, cubic boron nitride, and mixtures thereof, and attached at one of its surfaces to the uppermost layer remaining region, the intermediate layer having a wear resistance that is less than that of the uppermost layer remaining region; and a metallic substrate attached to the ultra hard body; wherein the uppermost layer is formed from diamond grains having an average particle size different from the diamond grains used to form the intermediate layer.