GLC/成分梯度CN_(x)多层膜的微观结构和摩擦学性能

Microstructure and Tribological Properties of Magnetron Sputtered Graphite-Like-Carbon/Composition-Gradient CN_(x) Multilayer Films

类金刚石碳膜通常内应力大、结合力低,而多层膜结构可提高结合力。采用磁控溅射技术在Si基体上沉积不同CNx层厚度的GLC/成分梯度CNx纳米多层膜。通过扫描电子显微镜(SEM)、X射线衍射仪(XRD)、X射线光电子能谱(XPS)、Raman光谱仪、球盘式摩擦仪、纳米压痕仪等对多层膜的表面形貌、微观结构、力学以及摩擦性能进行分析。结果表明:多层膜表面平整光滑,CNx层厚度为50 nm的多层膜有明显的层状结构。多层膜中存在石墨相而CNx以微晶或非晶存在。薄膜的sp3键含量、结合力、硬度等均随CNx层厚度的增加先增加后减小。CNx层厚度对多层膜的大气环境摩擦因数影响很小,但显著降低其真空环境摩擦因数。多层膜的硬度为(15~17.6)GPa,大气中的磨损率为(1.03~2.33)×10-16m3N-1m-1,真空中为(2.06~3.34)×10-16m3N-1m-1。CNx层厚度为20 nm的多层膜综合性能最佳。

Diamond-like-carbon film usually presents high internal stress and poor adhesion,whereas the multilayer architecture helps to improve its adhesion.Graphite-like-carbon(GLC)/composition-gradient CNx nano-multilayer films with different thicknesses of CNx single layer were prepared on silicon substrates by magnetron sputtering technique.The surface morphologies,microstructure,mechanical properties and tribological properties of the films were analyzed by SEM,XRD,XPS,Raman spectroscopy,ball-on-disk tribotester and nano-indentation tester,respectively.As the result,the surface of the multilayer film is smooth and the multilayer film with CNx single layer thickness of 50 nm displays an obviously layered structure.Graphitic phase exists in multilayer film while the CNx layers are microcrystalline or amorphous.The content of sp3 hybrid bonds,the adhesion and hardness of the film firstly increase and then decrease with the increase of CNx single layer thickness.The thickness of CNx single layer has little effect on the atmospheric friction coefficient of multilayer film,but it significantly reduces the friction coefficient in vacuum environment.The hardness of the multilayer film is(15~17.6)GPa,and the wear rate is(1.03~2.33)×10-16m3N-1m-1 in air and(2.06~3.34)×10-16m3N-1m-1 in vacuum.The multilayer film with CNx single layer thickness of 20 nm shows the best comprehensive performance.