Method of forming a thermally stable diamond cutting element

Abstract

A method for forming a diamond body includes placing a thermally stable polycrystalline diamond body and a first substrate into an enclosure, the thermally stable polycrystalline diamond body comprising a plurality of bonded diamond crystals and a plurality of interstitial regions between the bonded diamond crystals, the interstitial regions being substantially free of a catalyst material, heating the thermally stable polycrystalline diamond body and the first substrate to remove residual materials from the thermally stable polycrystalline diamond body, subjecting the thermally stable polycrystalline diamond body and the first substrate to a vacuum for evacuating such residual material, and pressing under high temperature the enclosure, the thermally stable polycrystalline diamond body and the first substrate while maintaining a vacuum in the enclosure to bond the thermally stable polycrystalline diamond body to the substrate.

What is claimed is: 
     
         1 . A method for forming a diamond body, comprising:
 placing a thermally stable polycrystalline diamond body and a first substrate into an enclosure, the thermally stable polycrystalline diamond body comprising a plurality of bonded diamond crystals and a plurality of interstitial regions between the bonded diamond crystals, the interstitial regions being substantially free of a catalyst material;   heating the thermally stable polycrystalline diamond body and the first substrate to remove residual materials from the thermally stable polycrystalline diamond body;   subjecting the thermally stable polycrystalline diamond body and the first substrate to a vacuum for evacuating residual materials from the thermally stable polycrystalline diamond body; and   pressing under high temperature the enclosure, the thermally stable polycrystalline diamond body, and the first substrate while maintaining a vacuum in the enclosure to bond the thermally stable polycrystalline diamond body to the substrate.   
     
     
         2 . The method of  claim 1 , further comprising: sintering diamond crystals and a catalyst material at high temperature and high pressure to form a polycrystalline diamond body. 
     
     
         3 . The method of  claim 2 , wherein the polycrystalline diamond body is formed unattached to a substrate. 
     
     
         4 . The method of  claim 2 , further comprising: removing at least a substantial portion of the catalyst material from the polycrystalline diamond body to form the thermally stable polycrystalline diamond body. 
     
     
         5 . The method of  claim 2 , wherein the catalyst material is provided in powder form and mixed with the diamond crystals prior to sintering. 
     
     
         6 . The method of  claim 2 , wherein prior to sintering, the diamond crystals and catalyst material are heated under a first vacuum. 
     
     
         7 . The method of  claim 1 , wherein an insulating material is disposed between the thermally stable polycrystalline diamond body and the enclosure such that the thermally stable polycrystalline diamond body does not contact the enclosure. 
     
     
         8 . The method of  claim 1 , further comprising: preventing contact of the thermally stable diamond body with the enclosure during the pressing. 
     
     
         9 . The method of  claim 1 , wherein the subjecting to a vacuum is performed after the heating is completed. 
     
     
         10 . The method of  claim 1 , further comprising sealing the enclosure by welding it closed to create a vacuum inside the enclosure. 
     
     
         11 . The method of  claim 1 , wherein the subjecting to a vacuum is initiated before the heating and maintained simultaneously with the heating. 
     
     
         12 . The method of  claim 1 , further comprising placing a braze material within the enclosure. 
     
     
         13 . The method of  claim 12 , wherein the heating comprises:
 heating to a first temperature to clean the thermally stable polycrystalline diamond body;   heating to a second temperature to melt the braze material; and   cooling to a third temperature to solidify the braze material, wherein the vacuum maintained as the braze material solidifies to create a vacuum sealed inside the enclosure.   
     
     
         14 . The method of  claim 1 , wherein, pressing under high temperatures comprises infiltrating the thermally stable polycrystalline diamond body with an infiltrant material. 
     
     
         15 . The method of  claim 14 , further comprising removing at least a portion of the infiltrant material from at least a portion of the bonded thermally stable polycrystalline diamond body. 
     
     
         16 . The method of  claim 1 , wherein the vacuum is approximately 10 −4  Torr or lower. 
     
     
         17 . A method for forming a diamond body, comprising:
 placing a thermally stable polycrystalline diamond body and a substrate into an enclosure, the thermally stable polycrystalline diamond body formed using high temperature and high pressure sintering conditions;   heating the thermally stable polycrystalline diamond body and the substrate to remove residual materials from the thermally stable polycrystalline diamond body; and   maintaining a vacuum in the enclosure while the enclosure, the thermally stable polycrystalline diamond body and the substrate are subjected to high temperature and high pressure to bond the thermally stable polycrystalline diamond body to the substrate,   wherein the high temperature and high pressure used in bonding are lower than the high temperature and high pressure sintering conditions.   
     
     
         18 . The method of  claim 17 , further comprising cooling the enclosure to room temperature after the heating, wherein after the cooling the vacuum is applied in the enclosure. 
     
     
         19 . The method of  claim 17 , wherein the vacuum is maintained by welding the enclosure closed to seal the enclosure. 
     
     
         20 . The method of  claim 17 , wherein the vacuum is maintained by melting and solidifying a braze material within the enclosure. 
     
     
         21 . The method of  claim 17 , wherein the vacuum is applied during the heating. 
     
     
         22 . The method of  claim 17 , further comprising: sintering diamond crystals and a catalyst material under the high temperature and high pressure sintering conditions to form a polycrystalline diamond body. 
     
     
         23 . The method of  claim 22 , wherein the polycrystalline diamond body is formed unattached to a substrate. 
     
     
         24 . The method of  claim 22 , further comprising: removing at least a substantial portion of the catalyst material from the polycrystalline diamond body to form the thermally stable polycrystalline diamond body. 
     
     
         25 . The method of  claim 22 , wherein the catalyst material is provided in powder form and mixed with the diamond crystals prior to sintering. 
     
     
         26 . The method of  claim 22 , wherein prior to sintering, the diamond crystals and catalyst material are heated under a first vacuum. 
     
     
         27 . The method of  claim 17 , wherein the vacuum is approximately 10 −4  Torr or lower.