Production method of fine grain polycrystalline diamond compact

Abstract

[Problem] This invention aims to provide a production method of a fine grain polycrystalline diamond compact which is suitable for finishing cutting tool materials and/or ultra-precision machining tool materials. In the method, a freeze-drying process for preventing the growth of secondary particle formation is unnecessary, and an aid does not need to be mixed in advance. [Means for Resolution] Disclosed is a following production method of a fine grain polycrystalline diamond compact. Each of carbonate and a C—H based organic compound which is a solid at room temperature, is sandwiched between diamond powder layers to stack them up in layers in a Ta capsule. Particle size of the diamond powder is 4 μm or less in average; and the organic compound is preferably one or more selected from among polyethylene, polypropylene and polystyrene. The layers in the capsule are sintered under the conditions of a pressure of 7.7 GPa or higher and a temperature of 2000° C. or higher. In the method, diamond powder as a raw material for sintering is prepared without any freeze-drying process; also the pre-mixture of an aid and an oxalic acid dihydrate which is a hazardous material, is not required.