Polycrystalline diamond construction and method for making same

Abstract

A polycrystalline diamond construction comprising a body of polycrystalline diamond material is formed of a mass of diamond grains exhibiting inter-granular bonding and defining a plurality of interstitial regions therebetween, and a non-diamond phase at least partially filling a plurality of the interstitial regions to form non-diamond phase pools, the non-diamond phase pools each having an individual cross-sectional area. The percentage of non-diamond phase in the total area of a cross-section of the body of polycrystalline diamond material and the mean of the individual cross-sectional areas of the non-diamond phase pools in the image analysed using an image analysis technique at a selected magnification is less than 0.7, or less than 0.340 microns squared, or between around 0.005 to 0.340 microns squared depending on the percentage of non-diamond phase in the total area of the cross-section of the polycrystalline diamond construction. The body of polycrystalline material in the construction has a cutting surface having a surface topology comprising one or more indentations therein and/or projections therefrom. There is also disclosed a method of making such a construction.

1 . A polycrystalline diamond construction comprising a body of polycrystalline diamond material formed of:
 a mass of diamond grains exhibiting inter-granular bonding and defining a plurality of interstitial regions therebetween, and   a non-diamond phase at least partially filling a plurality of the interstitial regions to form non-diamond phase pools, the non-diamond phase pools each having an individual cross-sectional area,   wherein the percentage of non-diamond phase in the total area of a cross-section of the body of polycrystalline diamond material is between around 0 to 5%, and the mean of the individual cross-sectional areas of the non-diamond phase pools in an analysed image of a cross-section through the body of polycrystalline material is less than around 0.7 microns squared when analysed using an image analysis technique at a magnification of around 1000 and an image area of 1280 by 960 pixels; and   wherein the body of polycrystalline material has a cutting surface having a surface topology comprising one or more indentations therein and/or projections therefrom.   
     
     
         2 . A polycrystalline diamond construction comprising a body of polycrystalline diamond material formed of:
 a mass of diamond grains exhibiting inter-granular bonding and defining a plurality of interstitial regions therebetween, and   a non-diamond phase at least partially filling a plurality of the interstitial regions to form non-diamond phase pools, the non-diamond phase pools each having an individual cross-sectional area,   wherein the percentage of non-diamond phase in the total area of a cross-section of the body of polycrystalline diamond material is between around 5 to 10%, and the mean of the individual cross-sectional areas of the non-diamond phase pools in an analysed image of a cross-section through the body of polycrystalline diamond material is less than around 0.340 microns squared when analysed using an image analysis technique at a magnification of around 1000 and an image area of 1280 by 960 pixels; and   wherein the body of polycrystalline material has a cutting surface having a surface topology comprising one or more indentations therein and/or projections therefrom.   
     
     
         3 . A polycrystalline diamond construction comprising a body of polycrystalline diamond material formed of:
 a mass of diamond grains exhibiting inter-granular bonding and defining a plurality of interstitial regions therebetween, and   a non-diamond phase at least partially filling a plurality of the interstitial regions to form non-diamond phase pools, the non-diamond phase pools each having an individual cross-sectional area,   wherein the percentage of non-diamond phase in the total area of a cross-section of the polycrystalline diamond construction is between around 10 to 15%, and   the mean of the individual cross-sectional areas of the non-diamond phase pools in an analysed image of a cross section through the body of polycrystalline material is less than around 0.340 microns squared when analysed using an image analysis technique at a magnification of around 3000 and an image area of 1280 by 960 pixels; and   wherein the body of polycrystalline material has a cutting surface having a surface topology comprising one or more indentations therein and/or projections therefrom.   
     
     
         4 . A polycrystalline diamond construction comprising a body of polycrystalline diamond material formed of:
 a mass of diamond grains exhibiting inter-granular bonding and defining a plurality of interstitial regions therebetween, and   a non-diamond phase at least partially filling a plurality of the interstitial regions to form non-diamond phase pools, the non-diamond phase pools each having an individual cross-sectional area,   wherein the percentage of non-diamond phase in the total area of a cross-section of the polycrystalline diamond construction is between around 15 to 30%, and   the mean of the individual cross-sectional areas of the non-diamond phase pools in an analysed image of a cross section through the body of polycrystalline material is between around 0.005 to 0.340 microns squared when analysed using an image analysis technique at a magnification of around 10000 and an image area of 1280 by 960 pixels; and   wherein the body of polycrystalline material has a cutting surface having a surface topology comprising one or more indentations therein and/or projections therefrom.   
     
     
         5 . A polycrystalline diamond construction according to any one of the preceding claims, wherein the body of polycrystalline diamond material has a largest dimension of around 6 mm or greater. 
     
     
         6 . A polycrystalline diamond construction according to any one of the preceding claims, wherein the body of polycrystalline diamond material has a thickness of around 0.3 mm or greater. 
     
     
         7 . The polycrystalline diamond construction according to any one of the preceding claims, further comprising a substrate bonded to the body of polycrystalline diamond material along an interface. 
     
     
         8 . The polycrystalline diamond construction according to  claim 7 , wherein the interface between the substrate and the body of polycrystalline diamond material is substantially non-planar. 
     
     
         9 . The polycrystalline diamond construction according to any one of  claim 7  or  8 , wherein the substrate comprises cemented carbide. 
     
     
         10 . The polycrystalline diamond construction according to any one of  claim 7  to  9 , wherein the substrate has a thickness at least equal to or greater than the thickness of the body of polycrystalline diamond material. 
     
     
         11 . The polycrystalline diamond construction according to any one of the preceding claims wherein the surface topology is on a first surface of the body of polycrystalline diamond material, the first surface being substantially free of material from a canister used in formation of the body of polycrystalline diamond material. 
     
     
         12 . The polycrystalline diamond construction according to  claim 11 , wherein the first surface is of the same quality as the bulk of the body of polycrystalline diamond material. 
     
     
         13 . The polycrystalline diamond construction according to any one of the preceding claims, wherein the body of polycrystalline diamond material has a thickness of up to around 6000 microns. 
     
     
         14 . An insert for a machine tool, comprising a cutter structure joined to an insert base, the cutter structure comprising the polycrystalline diamond construction as claimed in any one of  claim 1  to  13 , the surface topology being formed on a first face of the body of polycrystalline diamond material, the first surface forming a rake face or a cutting face, and the surface topology of the first surface forming chip-breaker topology. 
     
     
         15 . A cutter for boring into the earth comprising the polycrystalline diamond construction according to any one of the preceding claims. 
     
     
         16 . A PCD element for a rotary shear bit for boring into the earth, for a percussion drill bit or for a pick for mining or asphalt degradation, comprising the polycrystalline diamond construction of any one of  claim 1  to  13 . 
     
     
         17 . A drill bit or a component of a drill bit for boring into the earth, comprising a polycrystalline diamond construction according to any one of  claim 1  to  13 . 
     
     
         18 . A method for making a polycrystalline diamond construction, the method comprising:
 providing a mass of diamond grains having a first average size;   arranging the mass of diamond grains to form a pre-sinter assembly with a body of material for forming a substrate; and   treating the pre-sinter assembly in the presence of a catalyst material for diamond at an ultra-high pressure of around 7 GPa or greater and a temperature at which diamond is more thermodynamically stable than graphite to sinter together the diamond grains and a substrate bonded thereto along an interface to form an integral PCD construction; the diamond grains exhibiting inter-granular bonding and defining a plurality of interstitial regions therebetween, a non-diamond phase at least partially filling a plurality of the interstitial regions to form non-diamond phase pools, the non-diamond phase pools each having an individual cross-sectional area,   wherein the percentage of non-diamond phase in the total area of a cross-section of the body of polycrystalline diamond material is between around 0 to 5%, and the mean of the individual cross-sectional areas of the non-diamond phase pools in the image analysed is less than around 0.7 microns squared when analysed using an image analysis technique at a magnification of around 1000 and an image area of 1280 by 960 pixels; or   the percentage of non-diamond phase in the total area of a cross-section of the body of polycrystalline diamond material is between around 5 to 10%, and the mean of the individual cross-sectional areas of the non-diamond phase pools in the image analysed is less than around 0.340 microns squared when analysed using an image analysis technique at a magnification of around 1000 and an image area of 1280 by 960 pixels; or   the percentage of non-diamond phase in the total area of a cross-section of the polycrystalline diamond construction is between around 10 to 15%, and the mean of the individual cross-sectional areas of the non-diamond phase pools in the image analysed is less than around 0.340 microns squared when analysed using an image analysis technique at a magnification of around 3000 and an image area of 1280 by 960 pixels; or   the percentage of non-diamond phase in the total area of a cross-section of the polycrystalline diamond construction is between around 15 to 30%, and the mean of the individual cross-sectional areas of the non-diamond phase pools in the image analysed is between around 0.005 to 0.340 microns squared when analysed using an image analysis technique at a magnification of around 10000 and an image area of 1280 by 960 pixels;   the method further comprising forming a non-planar surface topology in a first surface of the body of polycrystalline diamond material, the surface topology comprising one or more indentations in and/or projections extending from the first surface.   
     
     
         19 . The method of  claim 18 , wherein the step of forming a non-planar surface topology in a first surface of the body of polycrystalline diamond material is during the step of treating the pre-sinter assembly in the presence of a catalyst material for diamond at an ultra-high pressure of around 7 GPa or greater and a temperature at which diamond is more thermodynamically stable than graphite to sinter together the diamond grains. 
     
     
         20 . The method of  claim 19 , wherein the step of forming the surface topology comprises:
 placing the mass of diamond grains into a canister,   placing a ceramic layer formed of a ceramic material in contact with the mass of diamond grains, the ceramic layer having a surface with surface topology, the surface topology imprinting a pattern in the mass of diamond grains complementary to the surface topology, the ceramic material being such that it does not react chemically with the diamond and/or a sinter catalyst material for the diamond grains, the method further comprising:   removing the ceramic layer from the body of polycrystalline material after the step of sintering the grains to form the integral PCD construction.   
     
     
         21 . A method according to  claim 20 , wherein the step of placing the ceramic layer in contact with the diamond grains comprises placing the ceramic material in direct contact therewith, or in indirect contact therewith through an interlayer of material, the material of the interlayer being such that it does not react chemically with the diamond material and/or a sinter catalyst material for the diamond grains. 
     
     
         22 . A method according to any one of  claim 18  to  21 , wherein the step of subjecting the diamond grains to a pressure comprises subjecting the grains to a pressure of greater than 7 GPa. 
     
     
         23 . A method according to any one of  claim 20  to  22 , wherein the step of placing the ceramic material in contact with the grains comprises placing a ceramic material formed of any one or more of the group of oxide ceramic materials that are not reduced by carbo-thermal reaction in contact with the grains. 
     
     
         24 . A method according to  claim 23 , wherein the ceramic material is formed of any one or more of the group of oxide ceramic materials comprising oxides of magnesia, calcia, zirconia, and/or alumina. 
     
     
         25 . A method according to any one of  claim 20  to  24 , wherein the step of placing the ceramic layer in contact with the aggregated mass of grains is after the step of placing the grains into a canister. 
     
     
         26 . A method according to any one of  claim 20  to  24 , wherein the ceramic layer is placed into the canister before the grains are placed in the canister. 
     
     
         27 . A method according to any one of  claim 20  to  26 , wherein step of forming the body of polycrystalline diamond material comprises forming a body having a free outer surface on removal of the ceramic layer therefrom in which the free outer surface is of the same quality as the bulk of the body of polycrystalline diamond material. 
     
     
         28 . A method according to any one of  claim 20  to  27 , comprising forming the body of PCD material on a substrate, the substrate being placed into the canister prior to sintering, the body of polycrystalline diamond material bonding to the substrate during sintering along an interface therebetween, the interface being substantially planar or non-planar. 
     
     
         29 . A method according to  claim 28 , wherein the substrate is formed of cemented carbide material. 
     
     
         30 . A method according to any one of  claim 20  to  27 , wherein the step of placing the mass of diamond grains into a canister comprises placing an aggregated mass of natural or synthetic diamond grains into the canister. 
     
     
         31 . A method according to any one of  claim 20  to  30 , wherein the step of removing the ceramic layer comprises removing the ceramic layer by impact. 
     
     
         32 . A method according to any one of  claim 20  to  31 , wherein the step of sintering comprises sintering at a temperature of between around 1300 to around 1800 degrees C. 
     
     
         33 . A method as claimed in any one of  claim 18  to  32 , further comprising treating the body of PCD material to remove catalyst material from interstices between inter-bonded grains in the PCD material after sintering. 
     
     
         34 . A method according to any one of  claim 20  to  33 , wherein the step of placing the diamond grains into the canister comprises providing a plurality of sheets comprising the grains and stacking the sheets in the canister to form an aggregation of grains. 
     
     
         35 . A method according to any one of  claim 20  to  33 , wherein the step of placing the diamond grains into the canister comprises depositing the grains into the canister using sedimentation or electrophoretic deposition techniques. 
     
     
         36 . A method according to any one of  claim 20  to  35 , further comprising constructing the surface topology of the ceramic material to impart a chamfered edge to the body of polycrystalline diamond material during sintering. 
     
     
         37 . A method of forming the polycrystalline diamond construction of any one of  claim 1  to  13 .