Pressure generation to 80 GPa using multianvil apparatus with sintered diamond anvils

Abstract

Experimental techniques for high-pressure generation have been developed using a multianvil apparatus with sintered diamond (SD) anvils. High-pressure cell assemblies have been optimized for SD anvils using a new Al₂O₃ pressure medium and baked pyrophyllite gaskets, which has enabled generation of pressures up to 80 GPa at room temperature. High-temperature experiments were also performed using cylindrical and graphite-windowed LaCrO₃ furnaces in the Al₂O₃ pressure medium to be suitable for in situ observations. Temperatures were generated up to 1600 K and stably maintained for more than 1 h at pressures up to 60 GPa. Present techniques using SD anvils can now reproduce the middle region of the Earth's lower mantle without sacrificing the great advantage of multianvil apparatus in stable and reproducible high-pressure and high-temperature generation.

Keywords:

• technical development
• high-pressure generation
• multianvil apparatus
• sintered diamond anvil
• in situ X-ray diffraction

Acknowledgements

We thank T. Kunimoto, T. Shinmei, Y. Kono, A. Yamada, N. Nishiyama, Y. Higo, and T. Inoue for their assistance in the synchrotron experiments. We are grateful to Y. Wang and an anonymous reviewer for their suggestions and comments. In situ high-pressure experiments were carried out at SPring-8 (proposal number: 2006A1754, 2006B1502, 2007A1868, 2007B1650-ND2b-np). This work is supported by a Grant-in-Aid for Scientific Research from the Japanese Government to T. Irifune.