Cutting tool insert

Abstract

A polycrystalline diamond (PCD) compact and method for making the compact are provided. The method includes bringing a first PCD wafer and a second PCD wafer together at an interface in the presence of a bonding agent to form an unbonded assembly and bonding the wafers together at the interface at a pressure and temperature at which diamond is thermodynamically stable. The first PCD wafer is more thermally stable than the second PCD wafer.

1 . A polycrystalline diamond compact comprising a first layer of polycrystalline diamond bonded to a second layer polycrystalline diamond, the first layer of polycrystalline diamond being more thermally stable and thinner than the second layer of polycrystalline diamond. 
     
     
         2 . A polycrystalline diamond compact according to  claim 1  wherein the first layer of polycrystalline diamond is thermally stable polycrystalline diamond. 
     
     
         3 . A polycrystalline diamond compact according to  claim 1  wherein the second layer of polycrystalline diamond contains a bonding phase comprising a solvent/catalyst. 
     
     
         4 . A polycrystalline diamond compact according to  claim 2  wherein the second layer of polycrystalline diamond contains a bonding phase comprising a solvent/catalyst. 
     
     
         5 . A polycrystalline diamond compact according to  claim 1  wherein the bonding between the two layers is direct diamond-to-diamond bonding. 
     
     
         6 . A polycrystalline diamond compact according to  claim 2  wherein the bonding between the two layers is direct diamond-to-diamond bonding. 
     
     
         7 . A polycrystalline diamond compact according to  claim 4  wherein the bonding between the two layers is direct diamond-to-diamond bonding.