Methods of forming polycrystalline elements from brown polycrystalline tables
View Patent ↗Methods of forming a polycrystalline table may involve disposing a plurality of particles comprising a superabrasive material, a substrate comprising a hard material, and a catalyst material in a mold. The plurality of particles may be partially sintered in the presence of the catalyst material to form a brown polycrystalline table having a first permeability attached to an end of the substrate. The substrate may be removed from the brown polycrystalline table and catalyst material may be removed from the brown polycrystalline table. The brown polycrystalline table may then be fully sintered to form a polycrystalline table having a reduced, second permeability. Intermediate structures formed during a process of attaching a polycrystalline table to a substrate may include a substantially fully leached brown polycrystalline table. The substantially fully leached brown polycrystalline table may include a plurality of interbonded grains of a superabrasive material.
1. A method of forming a cutting element for an earth-boring tool, comprising:
partially sintering particles of a superabrasive material in the presence of a catalyst material to form a brown polycrystalline table;
at least substantially fully removing the catalyst material from the brown polycrystalline table;
positioning the brown polycrystalline table proximate a substrate after at least substantially fully removing the catalyst material from the brown polycrystalline table; and
fully sintering the brown polycrystalline table in the presence of another catalyst material and the substrate to form a fully sintered polycrystalline table attached to the substrate.
2. The method of claim 1 , further comprising:
distributing additional particles comprising a non-catalyst material removable by a leaching agent among the particles of the superabrasive material before partially sintering; and
at least substantially fully removing the non-catalyst material from the brown polycrystalline table before fully sintering the brown polycrystalline table.
3. The method of claim 1 , further comprising maintaining grain growth of the particles comprising the superabrasive material during the partial sintering thereof within 5 μm or less of the size of the particles before partial sintering.
4. The method of claim 1 , further comprising:
partially sintering the particles of the superabrasive material in the presence of the catalyst material and another substrate to form a brown polycrystalline table attached to the other substrate; and
removing the other substrate before fully sintering the brown polycrystalline table.
5. The method of claim 1 , wherein positioning the brown polycrystalline table proximate the substrate comprises positioning the brown polycrystalline table adjacent to another fully sintered polycrystalline table attached to the substrate.
6. The method of claim 5 , further comprising exposing at least a portion of the substrate at a surface of the other fully sintered polycrystalline table to which the brown polycrystalline table is adjacent.
7. The method of claim 1 , wherein partially sintering the particles in the presence of the catalyst material to form the brown polycrystalline table comprises partially sintering the particles to form the brown polycrystalline table having greater than 10% by volume of catalyst material and any other material located in interstitial spaces among interbonded grains of the superabrasive material.
8. The method of claim 1 , wherein partially sintering the particles in the presence of the catalyst material to form the brown polycrystalline table comprises partially sintering the particles to form the brown polycrystalline table exhibiting, for a thickness of about 2 mm, a leach rate of less than about two weeks to substantially completely remove catalyst material from the brown polycrystalline table.
9. The method of claim 1 , wherein partially sintering the particles in the presence of the catalyst material to form the brown polycrystalline table comprises pressing the particles with at least about 5 GPa of pressure at a temperature of at least about 1,400° C. for less than about 5 minutes.
10. The method of claim 1 , wherein fully sintering the brown polycrystalline table to form the fully sintered polycrystalline table comprises fully sintering the brown polycrystalline table to form the fully sintered polycrystalline table comprising less than 10% by volume of interstitial spaces among interbonded grains of the superabrasive material.
11. The method of claim 1 , further comprising at least substantially fully removing the other catalyst material from at least a portion of the fully sintered polycrystalline table.