Polycrystalline diamond abrasive compacts

Abstract

This invention is for a polycrystalline diamond composite material comprising diamond particles and a binder phase, the polycrystalline diamond composite material defining a plurality of interstices and the binder phase being distributed in the interstices to form binder pools. The invention is characterised in that there is present in the binder phase a separate tungsten carbide particulate phase in excess of 0.05 total volume %, but not greater than 2 volume %, expressed as a % of the total composite material and that the tungsten carbide particulate phase is homogenously distributed in the composite material in such a manner that the relative standard deviation of the tungsten carbide grain size is less than 1. The invention extends to a method of manufacturing the composite material and to a polycrystalline diamond abrasive compact comprising the diamond composite material for use in cutting or abrading of a substrate or in drilling applications.

1 . A polycrystalline diamond composite material comprising diamond particles and a binder phase, the polycrystalline diamond composite material defining a plurality of interstices and the binder phase being distributed in the interstices to form binder pools, wherein there is present in the binder phase a separate tungsten carbide particulate phase in excess of 0.05 volume %, but not greater than 2 volume %, expressed as a % of the total composite material and the tungsten carbide particulate phase being homogenously distributed in the composite material in such a manner that the relative standard deviation of the tungsten carbide grain size (expressed as equivalent circle diameter) is less than 1. 
     
     
         2 . A polycrystalline diamond composite material according to  claim 1 , in which the tungsten carbide particulate phase is present in an amount not greater than 1.5 volume % expressed as a % of the total composite material. 
     
     
         3 . A polycrystalline diamond composite material according to  claim 1 , in which the tungsten carbide particulate phase is present in an amount not less than 0.1 volume % expressed as a % of the total composite material. 
     
     
         4 . A polycrystalline diamond composite material according to  claim 1 , in which the relative standard deviation of the tungsten carbide grain size (expressed as equivalent circle diameter) is less than 0.9. 
     
     
         5 . A polycrystalline diamond composite material according to  claim 1 , in which the relative standard deviation of the tungsten carbide grain size (expressed as equivalent circle diameter) is less than 0.8. 
     
     
         6 . A polycrystalline diamond composite material according to  claim 1 , in which the diamond particles have an average diamond grain size of less than 25 μm. 
     
     
         7 . A polycrystalline diamond composite material according to  claim 1 , in which the diamond particles have an average diamond grain size of less than 20 μm. 
     
     
         8 . A polycrystalline diamond composite material according to  claim 1 , in which the diamond particles have an average diamond grain size of less than 15 μm. 
     
     
         9 . A polycrystalline diamond composite material according to  claim 1 , in which the binder phase includes a catalyst/solvent for the diamond. 
     
     
         10 . A polycrystalline diamond composite material according to  claim 1 , in which the binder phase includes cobalt, nickel, iron or an alloy containing one or more of these metals. 
     
     
         11 . A polycrystalline diamond abrasive compact comprising a polycrystalline diamond composite material according to  claim 1 , in the form of a layer bonded to a surface of a cemented carbide substrate. 
     
     
         12 . A polycrystalline diamond abrasive compact according to  claim 11  wherein the substrate is cemented tungsten carbide substrate. 
     
     
         13 . A method of manufacturing a polycrystalline diamond composite material according to  claim 1 , comprising subjecting a powdered composition including diamond, finely particulate tungsten carbide particles uniformly distributed in the composition and present in an amount of 0.5 to 5 mass % of the composition to conditions of elevated temperature and pressure suitable for diamond synthesis. 
     
     
         14 . A method according to  claim 13  wherein the powdered composition includes a binder in particulate form. 
     
     
         15 . A method according to  claim 13 , in which the tungsten carbide particles are present in an amount of 1.0 to 3.0 mass % of the composition. 
     
     
         16 . A method according to  claim 13 , in which the tungsten carbide particles have a size of less than 1 μm. 
     
     
         17 . A method according to  claim 13 , in which the tungsten carbide particles have a size of less than 0.75 μm. 
     
     
         18 . A method according to  claim 13 , in which the powdered composition is placed on a surface of a cemented carbide substrate. 
     
     
         19 . A method according to  claim 13 , in which the cemented carbide substrate is a cemented tungsten carbide substrate. 
     
     
         20 . A method according to  claim 18 , in which the powdered composition forms a region adjacent the surface of the substrate on which it is placed and a layer of diamond particles is placed on the powdered composition. 
     
     
         21 . A polycrystalline diamond composite material according to  claim 1  substantially as herein described with reference to Example 1 or Example 2. 
     
     
         22 . A method of  claim 13  substantially as herein described with reference to Example 1 or Example 2.