적층형 셀과 아연도금층을 이용한 고온고압 합성다이아몬드의 압력변화에 따른 물성 연구 |
신운, 송오성 |
서울시립대학교 신소재공학과 |
Property of the HPHT Diamonds Using Stack Cell and Zn Coating with Pressure |
Yun Shen, Oh-Sung Song |
Department of Materials Science and Engineering, University of Seoul |
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ABSTRACT |
Fine diamond powders are synthesized with a 420 ${phi}$ cubic press and stack-cell composed of Kovar ($Fe_{54}Ni_{29}Co_{17}$) (or Kovar+7 ${mu}m$-thick Zn electroplated) alloy and graphite disks. The high pressure high temperature (HPHT) process condition was executed at $1500^{circ}C$ for 280 seconds by varying the nominal pressure of 5.7~10.6 GPa. The density of formation, size, shape, and phase of diamonds are determined by optical microscopy, field emission scanning electron microscopy, thermal gravimetric analysis-differential thermal ammnlysis (TGA-DTA), X-ray diffraction (XRD), and micro-Raman spectroscopy. Through the microscopy analyses, we found that 1.5 ${mu}m$ super-fine tetrahedral diamonds were synthesized for Zn coated Kovar cell with whole range of pressure while ~3 ${mu}m$ super-fine diamond for conventional Kovar cell with < 10.6 GPa. Based on $750^{circ}C$ exothermic reaction of diamonds in TGA-DTA, and characteristic peaks of the diamonds in XRD and micro-Raman analysis, we could confirm that the diamonds were successfully formed with the whole pressure range in this research. Finally, we propose a new process for super-fine diamonds by lowering the pressure condition and employing Zn electroplated Kovar disks. |
Key words:
HPHT, Super fine diamond, Kovar, Zn, Stack-cell |
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