▎ 摘　　要

NOVELTY - Formation of polycrystalline diamond, involves placing graphene nano-platelets into a capsule, and subjecting the platelets to a pressure of 10-20 GPa and a temperature of 1600-3000 degrees C to convert the platelets to nano-polycrystalline diamond. USE - Formation of polycrystalline diamond is used for superhard construction of tools used for cutting, milling, grinding, and drilling, as drill bit, rotary shear bit, percussion drill bit, rolling cone drill bit, hole opening tool, expandable tool, reamer, or other tools used for earth boring and rock drilling, for other abrasive applications, and as rotary fixed-cutter bit in oil and/or gas drilling (all claimed). ADVANTAGE - The method provides polycrystalline diamond having excellent abrasion resistance, impact resistance, fracture toughness, strength, and thermal stability. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for polycrystalline superhard construction. DESCRIPTION OF DRAWING(S) - The drawing shows a perspective view of a polycrystalline diamond cutter element or construction for a drill bit for earth boring. Cutting element (1) Superhard material (2) Substrate (3) Cutting face (4) Interface surface (8)