激光烧蚀中碳含量对甘油溅射特征的影响

Impact of Carbon Content in Carbon-doped Glycerol upon Laser Ablation Sputtering Characteristics

研究了激光等离子体推进中掺碳甘油在纳秒脉冲激光烧蚀后的烧蚀溅射特征。以石墨块材容器盛放不同质量分数的掺碳甘油工质,在波长1 064 nm,脉冲10 ns的YAG激光器不同能量的烧蚀下,分别进行靶动量、掺碳甘油散射斑和质量损失的采集。结果发现,随着激光能量的增强,溅射的甘油总量增加,液滴变小;随碳含量的增加,甘油溅射量明显降低,在碳含量达到5%时,观察不到甘油的溅射。该结果表明,碳掺杂能有效降低溅射量,但动量耦合系数与推进比冲随溅射量的减少也相应的降低,这是由于靶动量的产生主要来自于伴随等离子体产生而发生的液体溅射,同时掺碳甘油中聚焦点的转移也起到了部分作用。

Characteristics of the carbon-doped glycerol ablated by nanosecond laser pulse at different carbon contents are investigated at laser plasma propulsion. A graphite block vessel filled with carbon-doped glycerol is served as the propellant. The target momentum and the sputtering spot as well as the mass loss are melted and ablated by a YAG laser at different energy with 1064 nm wavelength and 10 ns pulse duration. Results show that with the energy increasing,the mass loss increases and the sizes of the droplet becomes smaller. Furthermore,the ejection volume decreases with the carbon content increasing. Glycerol sputtering cannot be observed at the carbon content of 5%. It means that carbondoped glycerol can reduces the sputtering efficiently. However,the coupling coefficient and specific impulse present decreasing tendency in this process. This is because that the target momentum is mainly determined by the glycerol ejection,as well as the laser focus position is varied by the doped carbon.