Method of making polycrystalline diamond material

Abstract

A method of making polycrystalline diamond material includes providing a fraction of diamond particles or grains and a sintering additive, the sintering additive comprising a carbon source of nano-sized particles or grains, forming the diamond particles and sintering additive into an aggregated mass, consolidating the aggregated mass and a binder material to form a green body, and subjecting the green body to conditions of pressure and temperature at which diamond is more thermodynamically stable than graphite and for a time sufficient to consume the sintering additive, sintering it and forming polycrystalline diamond material that is thermodynamically and crystallographically stable and is substantially devoid of any nano-structures.

1 . A method of making polycrystalline diamond material, the method including providing a fraction of diamond particles or grains and a sintering additive, the sintering additive comprising a carbon source of nano-sized particles or grains, forming the diamond particles and sintering additive into an aggregated mass, consolidating the aggregated mass and a binder material to form a green body, and subjecting the green body to conditions of pressure and temperature at which diamond is more thermodynamically stable than graphite and for a time sufficient to consume the sintering additive, sintering it and forming polycrystalline diamond material that is thermodynamically and crystallographically stable and is substantially devoid of any nano-structures. 
     
     
         2 . A method according to  claim 1 , wherein the binder material comprises a catalyst material for diamond. 
     
     
         3 . A method according to  claim 1 , wherein the sintering additive is nanodiamond. 
     
     
         4 . A method according to  claim 3 , wherein nanodiamond is UDD (ultra-dispersed nanodiamond), PDD (polycrystalline detonated diamond powder), or a crushed source of nanodiamond. 
     
     
         5 . A method according to  claim 1 , wherein the sintering additive is a nano-sized carbon source selected from the group comprising graphite, soot, coke, carbon anions and fullerenes. 
     
     
         6 . A method according to  claim 1 , wherein the sintering additive is provided in an amount of from about 0.01 to about 5 wt % of the aggregated mass, or from about 0.5 to about 1 wt % of the aggregated mass. 
     
     
         7 . A method according to  claim 1 , wherein the method includes subjecting the green body to a pressure of about 6.0 GPa or more and a temperature of about 1350° C. or more. 
     
     
         8 . A method according to  claim 1 , wherein the green body is sintered for a period of 2 minutes to 60 minutes. 
     
     
         9 . A method according to  claim 1 , wherein the diamond particles or grains, prior to contact with the sintering additive or binder material, have an average particle or grain size ranging from about 0.1 microns to about 50 microns. 
     
     
         10 . A method according to  claim 1 , wherein the step of subjecting the green body to a pressure treatment comprises subjecting the green body to a pressure of greater than 6.0 GPa, or at least about 6.2 GPa, or at least about 6.5 GPa, or at about 6.8 GPa or more, or at least about 8 GPa, or at least about 7.7 GPa, or at least about 7.5 GPa, or at least about 7.2 GPa, or at least about 7.0 GPa. 
     
     
         11 . A method according to  claim 1 , wherein the aggregated mass and the binder material are mixed in powder form with one or more binding aids. 
     
     
         12 . A method according to  claim 1 , wherein the step of consolidating the aggregated mass and binder material comprises coating the diamond particles with the binder material using any one or more of a sol-gel technique, electrolytic or electroless deposition, PVD, or CVD and consolidating the coated diamond particles with the sintering additive. 
     
     
         13 . A method according to  claim 1 , wherein the binder material is any one or more of cobalt-tungsten carbide, Ni, Pd, Mn or Fe. 
     
     
         14 . A body of polycrystalline diamond (PCD) material formed according to the method of  claim 1 . 
     
     
         15 . A tool or tool component for cutting, milling, grinding, drilling, earth boring, rock drilling, or the cutting and machining of metal, comprising an a body of PCD material formed according to the method of  claim 1 . 
     
     
         16 . A drill bit for boring into the earth for use in the oil and gas drilling industry comprising the tool of  claim 15 .