Thermally stable pcd with pcbn transition layer

Abstract

The present disclosure relates to cutting tools incorporating polycrystalline diamond bodies used for subterranean drilling applications, and more particularly, to a thermally stable polycrystalline diamond body joined to a substrate to form a cutting element. The thermally stable polycrystalline diamond body may be binderless polycrystalline diamond or a non-metal catalyst polycrystalline diamond. A polycrystalline cubic boron nitride layer is also provided, bonded on one side to the polycrystalline diamond body and on the other side to the substrate.

What is claimed is: 
     
         1 . A cutting element comprising:
 at least one thermally stable polycrystalline diamond body comprising a material microstructure comprising a plurality of bonded-together diamond crystals, wherein the thermally stable polycrystalline diamond body is selected from the group of bodies consisting essentially of binderless polycrystalline diamond bodies and non-metal catalyst polycrystalline diamond bodies;   a layer comprising polycrystalline cubic boron nitride, the layer being bonded to the thermally stable polycrystalline diamond body and having an interface surface; and   a substrate,   wherein the interface surface of the polycrystalline cubic boron nitride layer is bonded to the substrate.   
     
     
         2 . The cutting element of  claim 1 , wherein the at least one thermally stable polycrystalline diamond body comprises the non-metal catalyst polycrystalline diamond body, wherein the non-metal catalyst material is selected from the group consisting essentially of carbonates, sulfates, hydroxides, and iron oxides, and wherein the material microstructure further comprises interstitial regions between the diamond crystals, and the non-metal catalyst material occupying the interstitial regions. 
     
     
         3 . The cutting element of  claim 1 , wherein the at least one thermally stable polycrystalline diamond body comprises binderless polycrystalline diamond. 
     
     
         4 . The cutting element of  claim 3 , wherein the binderless polycrystalline diamond comprises a diamond volume content of at least 98%. 
     
     
         5 . The cutting element of  claim 1 , wherein the polycrystalline cubic boron nitride layer is bonded to the substrate by a braze layer. 
     
     
         6 . The cutting element of  claim 1 , wherein the polycrystalline cubic boron nitride layer is bonded to the substrate by high pressure high temperature sintering. 
     
     
         7 . The cutting element of  claim 1 , wherein the polycrystalline cubic boron nitride layer includes a mixture of polycrystalline cubic boron nitride and polycrystalline diamond. 
     
     
         8 . The cutting element of  claim 1 , wherein the at least one thermally stable polycrystalline diamond body comprises a plurality of bodies, at least one of which is surrounded by the polycrystalline cubic boron nitride layer. 
     
     
         9 . The cutting element of  claim 1 , wherein the at least one thermally stable polycrystalline diamond body comprises a top surface, a cutting edge meeting the top surface, and a bottom surface opposite the top surface, and wherein the bottom surface of the thermally stable polycrystalline diamond body is bonded to the polycrystalline cubic boron nitride layer. 
     
     
         10 . The cutting element of  claim 1 , wherein the polycrystalline cubic boron nitride layer comprises a ceramic binder or a metal binder. 
     
     
         11 . A shear cutter, comprising:
 a thermally stable polycrystalline diamond body comprising:
 an interface surface; 
 a top surface opposite the interface surface; 
 a cutting edge at the top surface; and 
 a material microstructure comprising a plurality of bonded-together diamond crystals; 
   a polycrystalline cubic boron nitride transition layer having opposite first and second surfaces;   a first bond between the first surface of the polycrystalline cubic boron nitride transition layer and the interface surface of the polycrystalline diamond body;   a substrate; and   a second bond between the second surface of the polycrystalline cubic boron nitride transition layer and the substrate,   wherein the thermally stable polycrystalline diamond body is selected from the group of bodies consisting essentially of binderless polycrystalline diamond bodies and non-metal catalyst polycrystalline diamond bodies.   
     
     
         12 . The shear cutter of  claim 11 , wherein the first bond comprises a ceramic binder. 
     
     
         13 . The shear cutter of  claim 11 , wherein the second bond comprises a braze. 
     
     
         14 . The shear cutter of  claim 11 , wherein the second bond is formed by high pressure high temperature sintering. 
     
     
         15 . A method for joining a thermally stable polycrystalline diamond body to a substrate, comprising:
 bonding a thermally stable polycrystalline diamond body to a polycrystalline cubic boron nitride body; and   bonding the polycrystalline cubic boron nitride body to a substrate.   
     
     
         16 . The method of  claim 15 , further comprising forming the thermally stable polycrystalline diamond body by sintering diamond particles and a non-metal catalyst at high temperature and high pressure to form a non-metal catalyst thermally stable polycrystalline diamond. 
     
     
         17 . The method of  claim 15 , further comprising forming the thermally stable polycrystalline diamond body by subjecting carbon to an ultra-high pressure, high temperature sintering process without a catalyst material, to form binderless thermally stable polycrystalline diamond. 
     
     
         18 . The method of  claim 15 , wherein bonding the thermally stable polycrystalline diamond body to the polycrystalline cubic boron nitride body comprises sintering the thermally stable polycrystalline diamond body in contact with cubic boron nitride particles at high temperature and high pressure. 
     
     
         19 . The method of  claim 15 , wherein bonding the polycrystalline cubic boron nitride body to the carbide substrate comprises brazing. 
     
     
         20 . The method of  claim 15 , wherein bonding the polycrystalline cubic boron nitride body to the carbide substrate comprises sintering cubic boron nitride particles in contact with a substrate at high temperature and high pressure.