• Korean Journal of Materials Research
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• v.10 no.9
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• pp.648-655
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• 2000

Synthesis of the crystalline film was investigated under the diamond growth condition with altering the addition of the nitrogen from 0% to 95%. With increasing the nitrogen concentration, surface morphology of the film was changed from the diamond film with {100} growth plane to the non-faceted diamond film with nano-scale grains. It also showed that the deposition of the diamond film could be synthesized using only methane and nitrogen gases without hydrogen gas. Separated particles with diamond structure showed an octahedral shaped I the nitrogen ranges between 30% and 80%, and newly formed hexagonal crystals are observed when substrate temperature with diamond structure, however, also identify that the hexagonal crystal was SiCN composite composed of Si, C and N atoms.

• Proceedings of the KAIS Fall Conference
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• 2011.05b
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• pp.854-857
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• 2011

육방정프레스 $420{\phi}$를 활용한 고온고압(high pressure high temperature: HPHT) 방법으로 금속촉매층 ($Ni_{77}Fe_{11}Mn_9Co_3$)과 카본디스크가 순차적으로 적층된 셀에 인산칼슘을 첨가함에 따라 합성다이아몬드 성장에 미치는 변화를 확인하였다. HPHT 공정의 압력, 온도, 시간을 각각 8 GPa, $1500^{\circ}C$, 280s로 고정하고, 카본과 금속촉매 층 사이에 인산칼슘을 각각 0, 0.08, 0.20, 0.28 mg씩 첨가하여 고온고압 합성을 수행하였다. 합성공정 후 적층셀의 중간부 셀 수직단면을 광학현미경과 마이크로 라만분광기로 분석하였다. 결과적으로 인산칼슘을 0.08 mg 도포하여 첨가하면 다이아몬드의 생성이 향상되었다. 반면 0.20 mg 이상에서는 도포되는 양이 증가 할수록 다이아몬드 생성이 억제되다가 0.28 mg 이상 첨가에서는 다이아몬드가 거의 생성되지 않는 특징을 보였다.

• The Journal of the Petrological Society of Korea
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• v.5 no.2
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• pp.129-134
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• 1996

Possibile phase transitions of graphite have been examined experimentally using piston cylinder and DAC with synchrotron radiation. The graphite-forming processes in high pressure and low temperature conditions and the phase change under super high pressure were studied in the conditions of 0.7 Gpa and 270-$360^{\circ}C$ in piston cylinder and under 39.6 Gpa in DAC. In the piston cylinder experiment using LiCO3as a catalyzer, we could synthesize disordered graphites whose TGD values change progressively form 9 to 53. It was known that the temperature of graphitization in 0.7 Gpa is between 270-$300^{\circ}C$. Numerous unknown XRD peaks were observed in the super high-pressure experiment. However, it is difficult to pick up a new peak of a hexagonal diamond phase. Application of the different high pressure apparatus as well as a peculiar X-ray source and various graphite specimen would be useful for super high-pressure experiment, and more detailed works are needed to characterize the unknown phase(s) observed in this study.

• The Journal of the Petrological Society of Korea
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• v.6 no.2
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• pp.88-95
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• 1997

High pressure X-ray diffraction study was carried out on a polycrystalline graphite to investigate the phase transition(s) at room temperature. Energy dispersive X-ray diffraction method was employed using a Mao-Bell type diamond anvil cell with an Wiggler synchrotron Radiation at the National Synchrotron Light Source. Sodium chloride power was used as the internal pressure sensor for the high pressure determinations as well as the pressure medium for quasihydrostatic pressure environment. Graphite transforms into a hexagonal didose not agree with the previously reported observations and this phase persists when pressure is released down to 0.1 MPa. This result dose not agree with the previously reported observations and this discrepancy would be due to the kinetics in phase transition as well as the uniaxially oriented pressure field in the diamond anvil cell.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2013.05a
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• pp.46-47
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• 2013

다이아몬드와 같은 $sp^3$ 결합을 가지며, 다이아몬드 다음으로 경도가 강한 입방정 질화붕소(cBN)는 철계금속가공에의 적합성 및 낮은 증착온도로 인하여 표면 코팅소재로의 응용이 크게 기대되어 왔다. 그러나 증착시 cBN 상의 핵생성 이전에 필연적으로 증착되는 비정질 질화붕소(aBN) 및 육방정 질화붕소(hBN) 층의 대기 하에서의 불안정성 그리고 cBN 상의 증착에 수반되는 높은 압축 잔류응력으로 인해 모재와의 밀착력이 낮아지는 문제점 등으로 인해 응용이 크게 제한되어져 왔다. 본 발표에서는 아르곤(Ar)과 질소($N_2$)를 반응가스로 이용하여 스퍼터링법으로 증착한 질화붕소에서 발생하는 높은 잔류응력의 원인과 이를 낮추기 위해 반응가스에 첨가한 수소의 효과에 대해서 상세히 고찰해 보고자 한다.