【摘要】 使脉冲激光与石墨粉在空气中相互作用,并对其氧化提纯．对产物进行的显微激光拉曼光谱(Raman)与高分辨电子显微镜(HRTEM)分析表明,产物中含大量纳米金刚石颗粒,其尺寸为5 nm左右,且具有较多的晶体缺陷和残余内应力．提出了石墨转变为金刚石纳米晶的机理:在脉冲激光产生的高温高压的条件下,具有石墨结构的原子团发生快速滑移切变,形成立方金刚石晶核,碳等离子体中高化学活性的碳粒子集团使金刚石晶核迅速长大,形成金刚石微晶．更多还原

【Abstract】 Graphite powders were irradiated by pulsed laser in atmosphere and normal pressure. The collected product was enriched by boiling in perchloric acid. The analysis on the Raman spectra and HRTEM suggests that diamond particles can be synthesized by pulsed laser and the particles size be about 5 nm. There are high defect density and internal stress in the synthetic diamond. The mechanism for synthesis of nanocrystalline diamond is that many graphite clusters turn into diamond nuclei by sliding and compressing in the laser-induced high temperature and high pressure state. The carbon plasma plays an important role in the processing, because it acts as a group of carbon ions with high chemical activation.更多还原