Ultrahigh pressure cell for materials synthesis

We describe here an apparatus for generating ultrahigh pressures and temper atures for materials synthesis. The system uses a spherically shaped explos ive charge to radially compress various materials contained within the samp le cavity. The results show the system is completely reproducible and, beca use of the geometry of the loading system, the workpiece that holds the pre cursor material is in excellent postshock condition. Samples are subjected to a pressure pulse of approximately 230 GPa for a period of 4 mu s. Using this system, C-60 has been compressed using a variety of quenching material s to attempt to generate diamond. Two organic precursors have also been tes ted to determine if the high stress conditions are suitable to synthesize b eta-carbon nitride. In this article, the design of the system, the numerica l modeling using Dyna East Finite Element Lagrangian and CTH hydrocodes, an d the results of the synthesis experiments will be presented. (C) 2000 Amer ican Institute of Physics. [S0034-6748(00)00807-8].