Over the past few years, amorphous carbon films with a single nanostructure have attracted enormous attention. However, multiple nanostructural amorphous carbon films with excellent mechanical and tribological properties have rarely been reported.

The research group headed by Prof. LIU Weimin and Dr. HAO Junying at the State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics (LICP), Chinese Academy of Sciences (CAS), has developed a self-assembled dual nanostructural amorphous carbon film with super high elastic recovery and near frictionless performance under high vacuum through radio frequency (13.56 MHz) magnetron sputtering deposition.

a) A typical loading–unloading curve; b) A frictional curve of the film (Image by LIU Weimin et al.)

A cross-linking network combined with fullerene-like nanostructure was observed in the film by high-resolution transmission electron microscopy (HRTEM). The film exhibited an extremely elastic recovery (about 95%). Interestingly, the film performed superior wear resistance and super-lubricity under vacuum even when the initial Hertzian contact pressure of the sliding surface was close to its hardness(Friction coefficient was as low as 0.001). The dual nanostructure significantly impacting the macroscale properties of carbon-based film will continuously be a design methodology for developing solid lubricating materials. Meanwhile, this kind of film has very important theoretical significance and practical value to save energy and reduce emission of the high-tech equipment and vehicle dynamic systems.

This work was received support from the National Natural Science Foundation of China (50905177) and the CAS (KJZD-EW-M01). The findings have been published in Advanced Materials (2012, 24, 4614-4617).