Methodof forming a diamond tooth insert for a drill bit and a diamond cutting element formed thereby

摘要

An improved bond between diamond and a metallic matrix can be achieved by hot pressing the metallic matrix onto a cleaned polycrystalline diamond (PCD) element. The PCD is degreased and then maintained substantially free from subsequent oxidation. The cleaned nonoxidized PCD is then disposed within a hot press and bonded under pressure and temperature with a conventional metallic matrix to form a cutting element. The cutting element thus formed is comprised of a PCD portion and a metallic portion with a high strength bond formed therebetween, on at least one surface of the diamond and, preferably, two adjacent surfaces. Typically, the metallic matrix is a carbide-forming metal or mixture of carbide-forming metals, and the diamond is a thermally stable porous, sintered polycrystalline product. The insert is subsequently placed within a bit mold and a bit is fabricated according to conventional powder metallurgical infiltration techniques. The diamond- to-metal bond in the insert remains stable during the furnacing of the infiltration bit, and a high-strength bond is formed between the metallic portion of the insert and the matrix body bit.