Minimization of nano-scale friction force of DLC films with the periodic structiues processed by a femto-seoond laser

飞秒激光加工周期性结构的 DLC 薄膜纳米级摩擦力最小化

• 批准号: 15560115
• 负责人: HONDA Tomomi
• 金额: $ 2.3万
• 依托单位: University of Fukui
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2004
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15560115/
• 关键词: Nano-tribology; DLC films; Femto-second laser; Nano-texturing; Low friction; Atomic force microscope; Adhesive force; Contact angle; 窒化物系セラミックス膜; 原子力間顕微鏡

It is known that the optimum surface roughness is capable of reducing lateral force. The pull-off force and lateral force were measured by using a scanning probe microscope (SPM) with various curvature radius of a spherical tip in air under the relative humidity controlled.(1)The frictional properties of the diamond-like carbon (DLC) films with the periodic structures were investigated in nano-scale using SPM. DLC films were prepared by an unbalanced magnetron sputtering method. The periodic structures have been generated on the surface of DLC films by polarized femto-second laser (τ=40fs, λ=800nm, F=10Hz) of energies nearby ablation threshold. The influence of normal load and relative humidity on the lateral forces was confirmed by the SPM. We used a silicon nitride rectangular cantilever with sharpened pyramidal tip or a spherical glass tip. Using the sharpened pyramidal tip, the lateral force of the DLC film with the periodic structures was higher than that of the film without the periodic structures. On the other hand, the lateral force of the DLC film with the periodic structures was lower than that of the film without the periodic structures using a spherical glass tip at low normal load and low relative humidity.(2)The tests were performed with two kinds of super-water-repellent coating films, which are the porous Al_2O_3+FAS and the flower-like Al_2O_3+FAS. The lateral force increases with the increase in the inclination of surface asperities in case of the SiN tip whose radius of curvature is too small. On the contrary, the lateral force hardly takes the influence of the inclination of surface asperities, and almost becomes constant value with the glass sphere tip whose radius of curvature is big.From these results, it is found that for the control of the friction force in nano-scale, the control of the surface roughness is effective and we can reduce the friction force using this method.

已知最佳表面粗糙度能够减小侧向力。利用扫描探针显微镜（SPM）测量了不同曲率半径的球形针尖在空气中的拉脱力和侧向力。（1）利用扫描探针显微镜（SPM）在纳米尺度上研究了周期性结构类金刚石（DLC）薄膜的摩擦性能。采用非平衡磁控溅射法制备了类金刚石薄膜。用能量接近烧蚀阈值的偏振飞秒激光（τ=40fs，λ=800nm，F=10Hz）在DLC膜表面产生了周期性结构。通过SPM验证了法向载荷和相对湿度对侧向力的影响。我们使用氮化硅矩形悬臂与尖锐的金字塔尖或球形玻璃尖。采用尖锐的锥尖，具有周期性结构的DLC膜的横向力高于不具有周期性结构的DLC膜。另一方面，在低法向载荷和低相对湿度下，使用球形玻璃尖端，具有周期性结构的DLC膜的横向力低于不具有周期性结构的膜的横向力。（2）对多孔Al_2O_3+FAS和花状Al_2O_3+FAS两种超拒水涂层进行了测试。在SiN针尖曲率半径过小的情况下，侧向力随着表面粗糙度的增大而增大。相反，侧向力几乎不受表面粗糙度倾角的影响，对于曲率半径较大的玻璃球针尖，侧向力几乎为一个常数，这表明在纳米尺度上控制摩擦力，控制表面粗糙度是有效的，可以降低摩擦力。