High-pressure and high-temperature generation using diamond/sic composite anvils prepared with hot isostatic pressing

Abstract

Using a hot isostatic pressing (HIP) technique, we synthesized diamond/SiC composites from diamond and Si powders. At an HIP condition of 1450 °C and 100 MPa, a pressure much lower than that of the diamond stability field, diamond powders react with molten Si to form well-sintered diamond/SiC composites. Cubes of the composites with 15 mm edge length were thereby fabricated, and an application to the second stage anvils in a Kawai-type high-pressure apparatus was attempted. A hybrid anvils system using four cubes of the composites and four of the conventional WC was introduced and heating experiments up to 1600 °C became possible. Because the diamond/SiC composites are transparent to X-rays, the present system is applicable not only to diffraction studies but also to radiographic studies that need a larger window for an X-ray image.

Keywords:

• Diamond composite
• SiC
• Hot isostatic pressing (HIP)
• High-pressure anvils
• Synchrotron radiation
• Multi-anvil high-pressure apparatus

Acknowledgements

We thank A. Hosomi of Tomei Diamond Inc. for the offer of diamond powder and S. Kume for invaluable comments. High-pressure in situ XRD experiments were performed with the approval of the Photon Factory Advisory Committee (Proposal Nos. 2002G063 and 2004G033). This work was supported in part by a Grant-in-Aid for Scientific Research of the Japanese Society for the Promotion of Science (JSPS).