Hostname: page-component-76fb5796d-2lccl Total loading time: 0 Render date: 2024-04-26T21:51:26.210Z Has data issue: false hasContentIssue false
  • English
  • Français

Microstructure and Mechanical Behaviors of Nano-polycrystalline Diamonds Synthesized by Direct Conversion Sintering under HPHT

Published online by Cambridge University Press:  26 February 2011

Hitoshi Sumiya  and
Tetsuo Irifune
Hitoshi Sumiya
Affiliation:
sumiya@sei.co.jp, Sumitomo Electric Industries, Electronics & Materials R&D Laboratories, 1-1-1, Koyakita, Itami, Hyogo, 664-0016, Japan, +81-72-772-4804, +81-72-770-6727
Tetsuo Irifune
Affiliation:
irifune@dpc.ehime-u.ac.jp, Ehime University, Geodynamics Research Center, 2-5, Bunkyo-cho, Matsuyama, 790-8577, Japan
Get access

Abstract

High-purity nano-polycrystalline diamonds have been synthesized by direct conversion from graphite and various non-graphitic carbons under static high pressures and high temperatures. The polycrystalline diamond synthesized from graphite at ≥15 GPa and 2300-2600 °C has a mixed texture comprising a homogeneous fine structure (particle size: 10-30 nm, formed in a diffusion process) and a lamellar structure (formed in a martensitic process), and has a very high Knoop hardness of 120-145 GPa. In contrast, the polycrystalline diamonds made from the non-graphitic carbons at ≥15 GPa and 1600-2000 °C have a single texture consisting of a very fine homogeneous structure (5-10 nm, formed in a diffusion process) without a lamellar structure. The hardness values of the nano-polycrystalline diamonds made from non-graphitic carbons (70-90 GPa) are significantly lower than that of polycrystalline diamond made from graphite. The investigation of the microstructure beneath the indentation of these nano-polycrystalline diamonds revealed that the existence of the lamellar structure and the bonding strength of the grain boundary have a decisive effect on the hardness.

Keywords

diamondmicrostructurehardness
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 987: Symposium PP – Materials Research at High Pressure , 2006 , 0987-PP03-01
Copyright
Copyright © Materials Research Society 2007

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Irifune, T., Kurio, A., Sakamoto, S., Inoue, T. and Sumiya, H., Nature 421, 599 (2003).Google Scholar
2. Sumiya, H., Irifune, T., Kurio, A., Sakamoto, S. and Inoue, T., J. Mater. Sci. 39, 445 (2004).Google Scholar
3. Sumiya, H. and Irifune, T., Diamond Relat. Mater. 13, 1771 (2004).Google Scholar
4. Sumiya, H., Yusa, H., Inoue, T., Ofuji, H. and Irifune, T., J. High Pressure Res. 26 63 (2006).Google Scholar
5. Irifune, T. and Sumiya, H., New Diamond and Frontier Carbon Technology 14, 313 (2004).Google Scholar
6. Sumiya, H., Rev. Sci. Instrum. 76, 026112 (2005).Google Scholar
7. Sumiya, H., Toda, N. and Satoh, S., Diamond Relat. Mater. 6, 1841 (1997).Google Scholar