递进式脉冲激光沉积CN_x薄膜的组织结构与摩擦学特性

采用脉冲激光沉积法(PLD)在不同激光通量下烧蚀CNx靶,在单晶硅基底上沉积CNx薄膜。利用扫描电子显微镜(SEM)、X射线能谱仪(EDS)、X射线光电子谱仪(XPS)等对薄膜的形貌、化学成分和微观结构进行了表征。采用球-盘式磨损试验机在大气(相对湿度48%～54%)环境下测试了薄膜的摩擦学特性。结果表明,递进式PLD技术可显著提高CNx薄膜的含氮量。当激光通量从5.0J/cm2提高至10.0J/cm2时,薄膜含氮原子数分数由23.8%上升至29.9%,膜中N-sp2 C键的含量上升,N-sp3 C键和sp3 C-C键的含量下降,薄膜的磨损率从2.1×10-15 m3/(N.m)上升至9.0×10-15 m3/(N.m)。摩擦系数为0.15～0.23,激光通量5.0J/cm2沉积的薄膜有最佳摩擦学性能。

Microstructure and Triobological Behavior of CNx Films Deposited by Iterative Pulsed Laser Deposition

The CNx films are deposited on monocrystalline silicon substrates by pulsed laser deposition (PLD) technique with different laser fluxes and CNx coating as the target. The morphology，composition and microstructure of the films are characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) respectively. The tribological behavior is investigated using a ball-on-disk tribometer in atmosphere (RH=48%~54%). The results show that an introduction of iterative PLD technique can improve the nitrogen content of the CNx films remarkably. With the increase of laser flux from 5 J/cm2 to 10 J/cm2, the percentage of N-sp2C bonding increases and the nitrogen atom fraction of the CNx film increases from 23.8% to 29.9%. A decreased percentage of N-sp3C and sp3C-C bonding of the CNx film are observed and the wear rate of CNx film increases from 2.1×10-15 m3/(N·m) to 9.0×10-15 m3/(N·m). The friction coefficient of the films ranges from 0.15 to 0.23. Compared with the others, the film deposited at laser flux 5 J/cm2 exhibites an optimal tribological performance.