毫秒脉冲激光辐照炭黑颗粒悬浮液制备纳米金刚石  

Preparation of nanodiamond from carbon black suspension by millisecond pulsed laser

作　　者：田飞[1] 孙景[1] 胡胜亮[1] 江雷[1] 

机构地区：[1]天津大学材料科学与工程学院,天津300072

出　　处：《金刚石与磨料磨具工程》2008年第6期17-20,30,共5页Diamond & Abrasives Engineering

基　　金：天津市自然科学基金重点资助项目(06YFJZJC01200)

摘　　要：采用较低功率密度（10^6W／cm^2左右）的Nd：YAG毫秒脉冲（脉宽0．2～20ms）激光辐照循环溶液中的经球磨的炭黑颗粒悬浮液，成功地合成出了尺寸在5nm左右的纳米金刚石，且粒度分布均匀，利用透射电镜对提纯前和提纯后的产物进行了分析，发现产物中同时存在纳米碳洋葱、石墨颗粒和金刚石颗粒。推测可能的相变机理是激光束辐照炭黑，因为激光束内能量分布不均匀，导致部分炭黑温度升高较小．颗粒经历低温退火作用后少量炭黑无序组织发生石墨化转变，体积收缩形成纳米碳洋葱。温度升高较大的炭黑组织大量发生石墨化转变，后续的能量导致石墨化组织再通过固-固切变机制转化为金刚石结构。Nd：YAG pulsed laser with a long pulse-width of millisecond and low power density （ 10^6 W/cm^2） was employed to irradiate the ball milling processed carbon black suspension that circulating within a recycle system driven by a pump 5 nm sized nanodiamonds with evenly distributed grit size were successfully synthesized. High resolution transmission electron microscope was used to characterize and analyse the morphology and structure of the as-prepared samples and the purified samples. Graphite nanoparticles, carbon onions and nanodiamonds were observed in the purified sample. We proposed that the uneven distribution of energy within a laser beam is the reason why products with different morphology and structure appear. At the exterior of laser ablated zone, the carbon black was heated up to rather low temperature, the disordered structure in carbon black could experience graphitization after laser ablation and resulted in the carbon onions. By comparison, the carbon black located in the interior of laser beam was heated up to high temperature and lead to the graphitization of carbon black, then the graphitized structure could be transformed into nanodiamond via solidsolid shear mechanism driven by the follow-up laser energy.

关 键 词：炭黑 纳米金刚石 脉冲激光 切变机制 

分 类 号：TQ164[化学工程—高温制品工业]