2022 Fiscal Year Final Research Report

Development of machinable boron-doped diamond

Research Project

PDF

Project/Area Number	21K18656
Research Category	Grant-in-Aid for Challenging Research (Exploratory)
Allocation Type	Multi-year Fund
Review Section	Medium-sized Section 17:Earth and planetary science and related fields
Research Institution	Japan Synchrotron Radiation Research Institute (2022) Okayama University (2021)
Principal Investigator	Tsujino Noriyoshi 公益財団法人高輝度光科学研究センター, 回折・散乱推進室, テニュアトラック研究員 (20633093)
Co-Investigator(Kenkyū-buntansha)	山崎大輔岡山大学, 惑星物質研究所, 准教授 (90346693)
Project Period (FY)	2021-07-09 – 2023-03-31
Keywords	ボロン添加ダイヤモンド / 快削性 / 高温高圧 / 融解実験 / 地球マントル
Outline of Final Research Achievements	In order to stably perform melting experiments of mantle materials under high-pressure conditions deeper than the Earth’s lower mantle using a Kawai-type multi-anvil press, we developed a method for synthesizing machinable sintered aggregates of boron-doped diamond (BDD), which has a high melting point and semiconducting properties. It was confirmed that the BDD sintered aggregates obtained in this study can be finely processed by cutting tools such as NC processing machines, and it is possible to generate a high temperature of 3000 K under the lower mantle pressure condition. It is also confirmed that the BDD heater does not greatly affect the efficiency of pressure generation. As a test, melting experiments of forsterite were carried out at 25 GPa, corresponding to the top of the lower mantle, and the partial molten part was observed in the recovered samples.
Free Research Field	高圧実験岩石学
Academic Significance and Societal Importance of the Research Achievements	地球内部を含むこれまでの地球の進化を紐解くことは、我々が住む地球の環境が今後どのように変化するのかを知る上で重要な手掛かりとなる。本研究では、地球形成初期に起きたとされる大規模熔融状態であった地球が冷却とともにどのように進化してきたのかを実験的に明らかにするための基盤を形成するものである。また、本研究では、半導体ダイヤモンドを真空または大気圧下で化学反応(原子拡散)によって合成できることを示しており、新規の材料開発の面においても非常に大きい意義を持つものである。