Method of forming a thermally stable diamond cutting element

A method of forming a thermally stable polycrystalline diamond cutting element, comprising:

• sintering a plurality of diamond crystals and a catalyst material at high temperature and high pressure to form a polycrystalline diamond material;
• removing substantially all of the catalyst material from at least a portion of the polycrystalline diamond material to form a thermally stable material;
• placing the thermally stable material and a substrate into an enclosure having an opening;
• sealing the enclosure for maintaining a vacuum inside the enclosure;
• and
• bonding the thermally stable material to the substrate inside the vacuum-sealed enclosure at high temperature and high pressure to form a bonded thermally stable polycrystalline diamond cutting element.

A method of forming a thermally stable polycrystalline diamond cutting element, comprising:

• forming a polycrystalline diamond material attached to a first substrate;
• separating the first substrate from the polycrystalline diamond material;
• leaching the polycrystalline diamond material to remove a substantial portion of a catalyst material and form a thermally stable polycrystalline diamond material having a residual portion comprising an oxide or gas;
• and
• bonding the thermally stable polycrystalline diamond material to a second substrate at a vacuum sufficient to remove at least 80% of the residual portion from the thermally stable polycrystalline diamond material.