1994 Fiscal Year Final Research Report Summary
High pressure apparatus for growth of diamond based on thermal pressure produced by constraining thermal expansion
| Project/Area Number |
05650125
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
機械工作・生産工学
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| Research Institution | Tokai University |
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Principal Investigator |
KAWASHIMA Yasushi Tokai Univ., Faculty of Engineering, Prof., 工学部, 教授 (80169721)
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| Project Period (FY) |
1993 – 1994
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| Keywords | High pressure apparatus / Thermal pressure / Synthesis of diamond / Growth of diamond / High pressure measurement |
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| Research Abstract |
The high pressure apparatus used for synthesis and growth of diamond has been usually a mechanical type of static high-pressure apparatus based on stress produced by an external force. But this type of apparatus requires a large hydraulic press and a solid pressure-transmitting medium and has a sliding part. The apparatus is complicated in structure and is accompanied by frictional force. Such problems are obstacles especially to scaling up of the apparatus.
A static high-pressure apparatus based on an internal force produced by constraining thermal expansion does not require a large hydraulic press and is not accompanied by frictional force. Therefore, the high-pressure chamber of this apparatus can be enlarged without losses of pressure due to frictional force. Furthermore, the high pressure created in the apparatus can be continuously measured by monitoring the force applied to constrain thermal expansion. In this study, in order to show that the apparatus is suitable for growth of diamond, a specimen composed of graphite and metallic catalyst for synthesis of diamond was subjected to pressure within the apparatus and attempt to synthesize diamond was done by using the apparatus, monitoring the force constraining thermal expansion. Results obtained by this study are as follows : 1. Pressures estimated from the force constraining thermal expansion are almost equal to those measured by using pressure dependence of melting points of lead and aluminum. 2. It was estimated by an x-ray diffraction study that a part of the graphite contained in the sample can be transformed into diamond. 3. The apparatus is capable of creating sustained high pressures required for growth of diamond.
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