Design of a novel large volume cubic high pressure apparatus for raising the yield and quality of synthetic diamond

Abstract

How to raise the yield of synthetic diamond is an important problem for the cubic high pressure apparatus (CHPA). In this paper, we present a novel CHPA to solve this problem, based on the design of the new structures of anvils and the sample cell assembly (two WC anvils with a square anvil tip and four WC anvils with a rectangular anvil tip are used to compress the tetragonal geometry cell). The achievement of consistent pressure and the distributions of the cell temperature have been analyzed by the finite element method and verified by the experimental data. Our results imply that the size of sample volume, compressed by the novel CHPA, is 125.02% larger than that of conventional CHPA (six WC anvils with a square anvil tip forming a cubic cell), which can dramatically raise the yield of synthetic diamond. Furthermore, the novel CHPA can be used for correspondence between the cell temperature and the cell pressure, which can dramatically increase the quality of synthetic diamond. This work has a direct effect on varying the pressing process of the conventional CHPA.