CN_x层厚度对DLC/CN_x多层膜结构和力学性能的影响

Effects of Single Layer Thickness of CN_x on Microstructure and Mechanical Properties of DLC/CN_x Multilayer Films

为了降低DLC膜的内应力,提高其力学性能,采用磁控溅射法在Si(100)基体上交替沉积了不同CN_x层厚度的DLC/CN_x纳米多层膜。利用X射线衍射仪(XRD)、扫描电镜(SEM)、X射线光电子能谱(XPS)、拉曼光谱(Raman)、纳米压痕仪、涂层附着力划痕仪和球盘式摩擦磨损试验机等分析了多层膜的微观组织、成键结构、力学和摩擦学性能。结果表明:所有DLC/CN_x多层膜均为非晶结构,结构致密,内应力低(约-475^-170 MPa),强化效应显著。随着CN_x层厚度的增大,CN_x膜内sp3键含量降低,DLC/CN_x多层膜的硬度和结合力逐渐降低,磨损率则逐渐上升。多层膜在真空和大气中的摩擦状态平稳,摩擦因数分别为0.16和0.2,CN_x层厚度的影响很小。CN_x层厚度为0.5 nm的多层膜的硬度可达36.9 GPa,结合力为27 N,在两种测试环境中均具有优异的摩擦学性能。

In order to reduce the intrinsic stress and improve the mechanical properties of DLC films, the DLC/CNx nanometer-multilayered films with various single layer thickness of CNx were deposited on Si（100） substrate by magnetron sputtering method. The microstructure, bonding structure, mechanical properties and tribological properties of the films were characterized by XRD, SEM, XPS, Raman spectroscopy, nano-indentation tester, scratch tester and ball-on-disc tribometer,respectively. The results show that all the DLC/CNx multilayer films have amorphous and compact structure and show low internal stress（in the range of-475 to-170 MPa） and strong reinforcement effect. As the mole content of sp3 bonds in the CNx film and the hardness and adhesion of the multilayer films decrease with the increase the single layer thickness of CNx, while the wear rate of the multilayer films increase gradually. The friction of the multilayer films in vacuum and air is stable, and the friction coefficient are 0.16 and 0.20, respectively. The single layer thickness of CNx has no obvious influence on the friction coefficient. The hardness of the multilayer film with a single CNx layer thickness of 0.5 nm attains 36.9 GPa, and the interface adhesion is 27 N, exhibiting excellent tribologiacl properties in the two test environments.