Double Sintered Thermally Stable Polycrystalline Diamond Cutting Elements

Abstract

Embodiments of the invention include a polycrystalline diamond compact comprising a plurality of double-sintered polycrystalline diamond segments. The polycrystalline diamond segments are configured to remain thermally stable at a first temperature. The polycrystalline diamond segments are positioned upon and bonded to a transition layer of single-sintered polycrystalline diamond that is configured to remain thermally stable at a second temperature lower than the first temperature. The transition layer is positioned upon and bonded to a substrate. Embodiments of the invention have improved thermally stability, resulting in fewer defects during manufacturing and improved longevity in use.

1 . A polycrystalline diamond compact comprising:
 a first layer, said first layer including a plurality of polycrystalline diamond segments positioned thereupon; said plurality of polycrystalline diamond segments being separated by an interfacial boundary formed of an abrasive material;   a second layer, said first layer being bonded to a second layer, said second layer being formed in part from said abrasive material; and,   a substrate, said second layer being positioned upon and bonded to said substrate.   
     
     
         2 . The compact of  claim 1 , wherein said polycrystalline diamond segments have a granular structure comprised of polycrystalline diamond grains and interstices, said interstices being substantially free of a catalytic material. 
     
     
         3 . The compact of  claim 2 , wherein said interstices include a non-catalytic material. 
     
     
         4 . The compact of  claim 3 , wherein said non-catalytic material is a non-metallic material. 
     
     
         5 . The compact of  claim 1 , wherein said polycrystalline diamond segments have a granular structure comprised substantially of polycrystalline diamond grains and substantially free of interstices. 
     
     
         6 . The compact of  claim 1 , wherein said abrasive material comprises a granular structure comprised of polycrystalline diamond grains and a catalyst. 
     
     
         7 . The compact of  claim 1 , wherein the second layer further comprises a substantially conical surface. 
     
     
         8 . The compact of  claim 1 , wherein said first layer is configured to remain thermally stable at a first temperature and said second layer is configured to remain thermally stable at a second temperature lower than said first temperature. 
     
     
         9 . A polycrystalline diamond compact comprising:
 a plurality of double-sintered polycrystalline diamond segments, said diamond segments configured to remain thermally stable at a first temperature;   a transition layer of single-sintered polycrystalline diamond configured to remain thermally stable at a second temperature lower than said first temperature, said polycrystalline diamond segments positioned upon and bonded to said transition layer; and,   a substrate, said transition layer positioned upon and bonded to said substrate.   
     
     
         10 . The compact of  claim 9 , wherein said polycrystalline diamond segments have a granular structure comprised of polycrystalline diamond grains and interstices, said interstices being substantially free of a catalytic material. 
     
     
         11 . The compact of  claim 10 , wherein said interstices include a non-catalytic material. 
     
     
         12 . The compact of  claim 11 , wherein said non-catalytic material is a non-metallic material. 
     
     
         13 . The compact of  claim 9 , wherein said polycrystalline diamond segments have a granular structure comprised substantially of polycrystalline diamond grains and substantially free of interstices. 
     
     
         14 . The compact of  claim 9 , wherein said transition layer comprises a granular structure comprised of polycrystalline diamond grains and a catalyst. 
     
     
         15 . The compact of  claim 9 , wherein the transition layer further comprises a substantially conical surface. 
     
     
         16 . A method of forming a polycrystalline diamond compact comprising:
 providing a canister configured to receive a plurality of sintered polycrystalline diamond segments and an unsintered abrasive powder;   filling said canister with said unsintered abrasive powder;   positioning said plurality of polycrystalline diamond segments upon said unsintered abrasive powder, an interfacial boundary formed of said unsintered abrasive powder separating each of said plurality of polycrystalline diamond segments; and   applying a temperature and a pressure to said canister to sinter said unsintered abrasive powder and bond said polycrystalline diamond segments to said sintered abrasive powder.   
     
     
         17 . The method of  claim 16 , further comprising positioning a substrate in said canister, said unsintered abrasive powder being positioned between said substrate and said sintered polycrystalline diamond segments. 
     
     
         18 . The method of  claim 16 , further comprising:
 providing another canister configured to receive at least a first disc, said first disc including at least one rib on a front surface of said first disc;   filling said canister with at least diamond powder;   placing said first disc in said canister such that said front surface of said first disc is in contact with said diamond powder; and,   applying a temperature and a pressure to said canister to sinter said diamond powder to form said sintered polycrystalline diamond segments.   
     
     
         19 . The method of  claim 18 , further comprising:
 removing said sintered polycrystalline diamond segments from said another canister;   processing said polycrystalline diamond segments to make said polycrystalline diamond segments more thermally stable than unprocessed polycrystalline diamond segments.