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. 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.   
     
     
         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.   
     
     
         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.   
     
     
         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.   
     
     
         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  claims 7  or  8 , wherein the substrate comprises cemented carbide. 
     
     
         10 . The polycrystalline diamond construction according to any one of  claims 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 . A cutter for boring into the earth comprising the polycrystalline diamond construction according to any one of the preceding claims. 
     
     
         12 . 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  claims 1  to  10 . 
     
     
         13 . A drill bit or a component of a drill bit for boring into the earth, comprising a polycrystalline superhard construction according to any one of  claims 1  to  10 . 
     
     
         14 . 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.   
     
     
         15 . A method of forming the polycrystalline diamond construction of any one of  claims 1  to  10 . 
     
     
         16 . A polycrystalline diamond construction substantially as hereinbefore described with reference to any one embodiment as that embodiment is illustrated in  FIGS. 3 to 10   b  of the accompanying drawings. 
     
     
         17 . A method of forming the polycrystalline diamond construction substantially as hereinbefore described with reference to any one embodiment as that embodiment is illustrated in  FIGS. 3 to 10   b  of the accompanying drawings.