Pressure generation to 65 GPa in a Kawai-type multi-anvil apparatus with tungsten carbide anvils

ABSTRACT

We have expanded the pressure ranges at room and high temperatures generated in a Kawai-type multi-anvil apparatus (KMA) using tungsten carbide (WC) anvils with a high hardness of H_v = 2700 and a Young’s modulus of 660 GPa. At room temperature, a pressure of 64 GPa, which is the highest pressure generated with KMA using WC anvils in the world, was achieved using 1°-tapered anvils with a 1.5-mm truncation. Pressures of 48–50 GPa were generated at high temperatures of 1600–2000 K, which are also higher than previously achieved. Tapered anvils make wide anvil gaps enabling efficient X-ray diffraction. The present pressure generation technique can be used for studying the upper part of the Earth’s lower mantle down to 1200 km depth without sintered diamond anvils.

KEYWORDS:

• Kawai-type multi-anvil apparatus
• tungsten carbide anvil
• sintered diamond anvil
• synchrotron
• lower mantle

Acknowledgements

We thank H. Kagi and two anonymous reviewers for their fruitful suggestions comments. The synchrotron radiation experiments were performed at the BL04B1 of SPring-8 with the approval of the Japan Synchrotron Radiation Research Institute (JASRI) (Proposal Nos. 2015B1319, 2015B1504, 2015B1761, 2016A1172, and 2016A1434).

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study is also supported by the research project approved by DFG (KA-3434/7, KA-3434/8 and KA-3434/9) and BMBF (05K16WC2) to T. Katsura and by the Overseas Research Fellowship from the Scientific Research of the Japan Society for the Promotion of Science (JSPS) for Young Scientists to T. I.