Polycrystalline diamond

Abstract

A polycrystalline diamond (PCD) material 10 comprising at least 88 volume percent and at most 99 volume percent diamond grains 12 , the mean diamond grain contiguity being greater than 60.5 percent. The PCD material 10 is particularly but not exclusively for use in boring into the earth.

1 - 15 . (canceled) 
     
     
         16 . A method of making PCD material, the method including subjecting an aggregated mass of diamond grains to a pressure treatment at a pressure of greater than 6.0 GPa in the presence of a metallic catalyst material for diamond at a temperature sufficiently high for the catalyst material to melt, and sintering the diamond grains to form PCD material; the diamond grains having the size distribution characteristic that at least 50 percent of the grains have average equivalent circle diameter (ECD) size greater than 5 microns, and at least 20 percent of the grains have average ECD size in the range from 10 to 15 microns. 
     
     
         17 . A method as claimed in  claim 16 , including subjecting the PCD material to a further pressure treatment at a pressure of at least about 2 GPa. 
     
     
         18 . A method as claimed in  claim 16 , including removing metallic catalyst material for diamond from interstices between the diamond grains of the PCD material. 
     
     
         19 . A method as claimed in  claim 16 , including subjecting the PCD material to a heat treatment at a temperature of at least about 500 degrees centigrade for at least about 5 minutes. 
     
     
         20 . A method as claimed in  claim 16 , including introducing an additive material into the aggregated mass, the additive material containing at least one element selected from V, Ti, Mo, Zr, W, Ta, Hf, Si, Sn or Al. 
     
     
         21 - 27 . (canceled)