Next-generation surface design technology due to femtosecond-laser-induced nanostructure formed on hard thin films

本文报道了飞秒激光脉冲纳米结构的DLC、TiN、CrN薄膜和GC衬底的宏观和微观摩擦特性。在宏观摩擦性能方面，DLC和GC炭材料的摩擦系数明显低于TiN和CrN炭材料。对于淬火钢球，类金刚石的摩擦系数μ随激光功率的增大而减小，并由于类金刚石改成了GC而接近于GC的μ。在1.5mN的超轻载荷下，用微划痕试验测量了纳米结构表面的摩擦系数μ。在此条件下，类金刚石、氮化钛和氮化铬纳米结构表面的μ比未辐照的表面有所增加。而在低激光能量照射下，GC的μ表现出最小值0.05后随激光功率的增大而增大。

This paper reports macro and micro frictional properties of DLC, TiN, CrN films and GC substrate of which surfaces are nanostructured with femtosecond (fs) laser pulses. As for the macro frictional properties, the friction coefficients of carbon materials of DLC and GC exhibited fairly lower values compared with those of TiN and CrN. The friction coefficient μ of DLC obtained for a hardened steel ball decreased with an increase of the laser power and approached to μ of GC because of the modification from DLC to GC. The friction coefficient μ of the nanostructured surface was measured with a micro-scratch test at an ultralight load of 1.5mN. For this condition, μ of the nano -structured surface of DLC, TiN, and CrN increased, compared with those of the non-irradiated surface. On the other hand, μ of GC irradiated at a low laser energy has shown a minimum value of 0.05 and then increases with an increase of the laser power.