METHOD OF SYNTHESIS OF DIAMOND PHASES IN GRAPHITE Russian patent published in 1997 - IPC

FIELD: production of extra hard materials. SUBSTANCE: invention consists in that pressure and temperature required for occurring graphite-diamond transition are generated by electric explosion of metal foil applied onto dielectric insert on outer surface of carbon-containing specimen being in the form of a hollow cylinder. Cylindrical form of specimen ensures most full reaction and maximum dimensions of synthesis zone provided that wall thickness exceeds inner radius at least by four times. Availability of inner hollow prevents the specimen from collapse and destruction because of cumulation effect arising from convergence of shock waves to symmetry axis. To avoid internal breakings off in hollow, the latter is filled with damping viscous material, which is pressed out through end surfaces. Outer surface of explosive foil is covered with sealing layer of plastic dielectric material, its thickness and density being chosen such as to provide its weight to be not less than that of carbon-containing specimen. This condition prevents occurring of premature discharge and provides required duration of maintenance of pressures and temperatures on specified level. EFFECT: achieved high compression degree with no subsequent destruction of material. 3 dwg