In situ synthesis of polyimide-based solid lubricating films on the surface of aluminium alloy with improved tribological performance

Polyimide-based solid lubricating films were prepared by simple and efficient spin coating proceeding. Several composite lubricating films were obtained by changing the composition and contents of inorganic solid lubricants in organic binder. The structure, physical phase, and performance of the synthesised lubricating films were characterised by using X-ray diffraction, scanning electron microscope, fourier transform infrared spectrometry, thermo gravimetric analyzer, and nano-indentation methods. And the friction coefficients of these composite lubricating films were measured by pin-on-disk structural tribometer. The results showed that all kinds of lubricating films had good adhesion strength. Compared with the pure polyimide film, the composite lubricating films exhibited better thermal and mechanical properties. These composite lubricating films, with MoS2 and graphite as solid lubricants, could effectively reduce the friction coefficient of polyimide film. Moreover, the friction coefficient of the composite lubricating film filled with the above two kinds of lubricant decreased to the minimum 0.141.