中文摘要：

为了提高激光合成纳米金刚石的效率,对不同的激光器作用于不同的碳原料悬浮液的合成效果进行了研究。以Nd：YAG毫秒脉冲激光（功率密度为106W.cm-2）作用于土状石墨,成功合成了纳米金刚石,实现了较低激光功率密度下的制备,有利于提高合成效率;以红宝石纳秒脉冲激光（功率密度〉109W.cm-2）作用于鳞片石墨合成了纳米金刚石;以上2种激光没有使碳黑转变为纳米金刚石。较低功率密度（106W.cm-2）毫秒脉冲激光照射石墨悬浮液时,其相变机理为：石墨颗粒吸收激光能量快速升温并达到熔融状态,激光脉冲过后,碳液滴迅速冷却,进入金刚石稳定区,金刚石形核并长大。

英文摘要：

In order to improve output rate of nanodiamond synthesized by laser irradiation, a process that the graphite particles suspended in water is irradiated by laser beam was proposed. Nanodiamonds were synthesized sueessfully with flake and scale like graphite powders being irradiated by pulsed Nd-YAG laser with power density （10^6W·cm^-2） and pulsed ruby laser with higher power density （〉 10^9 W·cm^-2）. For the laser beam with power density （106W·cm^-2）, the mechanism of the phase transformation in the process is that the graphite is molten by the caser pulse, and nanodiamonds nucleate and grow up in the liquid carbon cooled qcickly.