Nano-polycrystalline diamond synthesized through the decomposition of stearic acid

Hideaki Kawamura, Hiroaki Ohfuji

Research output: Contribution to journalArticlepeer-review

Abstract

Here we report a novel route for synthesizing nano-polycrystalline diamond (NPD) using stearic acid (C18H36O2) as a starting material under high pressure and high temperature. The obtained NPD shows a transparent dark-yellowish color similar to the standard NPD synthesized from graphite and consists of extremely fine diamond grains (∼10 nm). The temperature required for the present synthesis of pure transparent NPD is as low as 1000°C at 13 and 17 GPa, which is surprisingly lower than that for conventional NPD synthesis (1800–2000°C). The amorphous-like, extremely poorly crystalline graphite produced by the thermal decomposition of stearic acid likely provides preferential nucleation sites for diamond and significantly lower the activation energy. The removal of volatile components such as H2O generated through the decomposition from the system is a key to obtain pore-free transparent NPD. Magnesite, MgCO3 and periclase, MgO can be used as an efficient H2O remover through the hydration reaction.

Original languageEnglish
JournalHigh Pressure Research
DOIs
Publication statusAccepted/In press - 2020
Externally publishedYes

Keywords

  • Nano-polycrystalline diamond
  • high pressure and high temperature
  • multi-anvil apparatus
  • stearic acid
  • transmission electron microscopy

ASJC Scopus subject areas

  • Condensed Matter Physics

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