Sintered Diamond and Research of the Earth's Interior

Abstract

The maximum attainable pressure in a Kawai-type of high-pressure apparatus (KHA) is limited to about 27 GPa when using tungsten carbide (WC) as the anvil material. Recently a remarkable innovation has been made for the KHA by adopting sintered diamond (SD) as the anvil material. So far pressures up to 50 GPa have been confirmed in SD anvil assemblies without any reduction of the specimen volume. Therefore, phase equilibrium and melting experiments of Earth materials have been extended to conditions deep into the lower mantle. The results will substantially advance our understanding of the structure of the lower mantle and the state of the Earth early in its history.