CAJ | 학술논문

以圆葱碳( OLC11 ,1 100 ℃及1 Pa条件下退火处理纳米金刚石所得)为原料,在500~1 400 ℃/4~6 GPa/5~30 min条件下烧结合成无添加剂纳米晶聚晶金刚石( NPCD)块体. XRD、HRTEM、FESEM、维氏硬度等分析表明,高温高压烧结后,OLC11转变为金刚石,同时金刚石颗粒长大连接形成D-D型NPCD块体. NPCD主要由金刚石组成,还含有石墨和少量无定形碳. NPCD内存在大量纳米孪晶. 烧结温度对NPCD的晶粒尺寸、密度、维氏硬度影响较大,烧结压力的影响较小. 1 200 ℃/5.5 GPa/15 min合成的NPCD平均晶粒尺寸、密度和维氏硬度指标较好,分别为10.7 nm、2.70 g/cm3 和32 GPa. 烧结过程中,高温高压使得OLC11石墨层由内而外破裂形成金刚石颗粒,相邻OLC11通过悬键连接形成金刚石大颗粒,再通过D-D键键合形成NPCD块体.
이원총탄( OLC11 ,1 100 ℃급1 Pa조건하퇴화처리납미금강석소득)위원료,재500~1 400 ℃/4~6 GPa/5~30 min조건하소결합성무첨가제납미정취정금강석( NPCD)괴체. XRD、HRTEM、FESEM、유씨경도등분석표명,고온고압소결후,OLC11전변위금강석,동시금강석과립장대련접형성D-D형NPCD괴체. NPCD주요유금강석조성,환함유석묵화소량무정형탄. NPCD내존재대량납미련정. 소결온도대NPCD적정립척촌、밀도、유씨경도영향교대,소결압력적영향교소. 1 200 ℃/5.5 GPa/15 min합성적NPCD평균정립척촌、밀도화유씨경도지표교호,분별위10.7 nm、2.70 g/cm3 화32 GPa. 소결과정중,고온고압사득OLC11석묵층유내이외파렬형성금강석과립,상린OLC11통과현건련접형성금강석대과립,재통과D-D건건합형성NPCD괴체.
The onion-like carbon(OLC11) was synthesized by annealing nanodiamond at 1 100 ℃with 1 Pa, which was taken as raw material in the sintering process at 500~1 400 ℃/4~6 GPa/5~30 min, yielding an additive-free nanopolycrystalline diamond( NPCD) blocks. The XRD, HRTEM, FESEM and Vickers-hardness testing results showed that OLC11 particles were converted into diamond after being sintered at high temperature, which grew up and bonded together forming D-D type NPCD block. NPCD was composed of diamond, graphite and trace of amorphous carbon, with many nanotwins. The sintering temperature had bigger influence on the grain size, density and Vickers-hardness of the NPCD, while the sintering pressure had the less impact. The NPCD synthesized at 1 200℃/5.5 GPa/15 min is better in the average diamond grain size, density and Vickers hardness, reaching 10.7 nm, 2.70 g/cm3 and 32 GPa, respectively. In the sintering process, elevated temperature and pressure had forced the OLC11 graphite broken from inside toward outside, forming nanodiamond particle, with the adjacent OLC11 particles bonded together through dangling bonds to form larger nanodiamond particles, which was then bonded to become NPCD through D-D bond.