Methods of forming polycrystalline bodies using rhombohedral graphite materials

Abstract

Methods of synthesizing polycrystalline bodies using rhombohedral graphite materials are disclosed and described. One procedure includes providing a particulate graphite source having a majority of carbon atoms oriented in a rhombohedral polytype configuration. The particulate graphite source can be shaped into a desired shape having a porosity from about 0% to about 30%. A sufficient amount of heat and pressure can be applied to the desired shape to form diamond and consolidate the diamond into a polycrystalline body.

Description

RELATED APPLICATIONS [0001] This application is a divisional application of U.S. patent application Ser. No. 10 / 900,037, filed Jul. 26, 2004 which application claims the benefit of U.S. Provisional Patent Application No. 60 / 490,170, filed Jul. 25, 2003, each of which are incorporated herein by reference in their entireties.FIELD OF THE INVENTION [0002] The present invention relates to methods for synthesizing polycrystalline bodies. Accordingly, this invention involves the fields of chemistry, materials science, metallurgy, and geology. BACKGROUND OF THE INVENTION [0003] The production of synthetic diamond is a process that has received much attention over the years and been sought for a variety of industrial applications. Today a number of diamond synthesis processes are known, several of which have been successfully commercialized. Examples of various diamond synthesis methods can be found in U.S. Pat. Nos. 2,947,611; 3,030,188; 3,238,019; 3,401,019; 4,377,565; 4,483,836; 5,209,91...

AI Technical Summary

Benefits of technology

[0007] Accordingly, the present invention provides methods of improved efficiency for synthesizing superabrasive particles from a superabrasive precursor. The superabrasive precursor can include a source material distributed in a metal matrix. The source material can be a rhombohedral graphite source having a majority of carbon atoms oriented in a rhombohedral polytype configuration. The rhombohedral graphite source is suitable for synthesis of diamond particles. Alternatively, the source material can be hexagonal boron nitride which is suitable for synthesis of cubic boron nitride particles. A shock wave can be passed through the source material that is sufficient to convert the source material to superabrasive particles.

[0010] Once the carbon is dissolved in the molten metal and has been converted to the rhombohedral polytype of graphite, the metal can be solidified in preparation to receive a shock wave. Optionally, prior to solidification, the metal can be shaped into a number of configurations that facilitate easy handling thereof, and which can in some respects contribute to the ease of converting graphite to diamond. Further some shapes can allow use of various shock wave sources which may otherwise be ineffective. Examples of such shapes include without limitation, bars, sheets, rods, etc. Additionally, the solidified metal containing the rhombohedral graphite can be cut into sections, or otherwise reduced in size or shaped, following solidification, but prior to application of the shock wave.

[0014] In some instances, it can be advantageous to remove the graphite from the metal once it has been converted to the rhombohedral form, and before the shock wave is applied to convert it to diamond. By so doing, it is possible to greatly improve the efficiency of making diamond tools or masses by converting the rhombohedral graphite into diamond as part of the tool fabrication process. In this manner the extra step of heating and pressing the graphite simply to convert the graphite to diamond can be avoided, and the overall process of producing diamond tools, or a polycrystalline diamond mass is greatly improved.

Problems solved by technology

Further some shapes can allow use of various shock wave sources which may otherwise be ineffective.

Images