Structural and tribological properties of polyimide/Al _2O _3/SiO _2 composites in atomic oxygen environment

摘要

Effects of atomic oxygen (AO) irradiation on the structural and tribological behaviors of polyimide/Al _2O _3/SiO _2 composites were investigated in a ground-based simulation facility, in which the energy of AO was about 5 eV and the flux was 7.2×10 ~(15) cm ~(-2).s ~(-1). The structural changes were characterized by X-ray photoelectron spectroscopy (XPS) and attenuated total-reflection FTIR (FTIR-ATR), while the tribological changes were evaluated by friction and wear tests as well as scanning electron microscopy (SEM) analysis of the worn surfaces. It was found that AO irradiation induced the oxidation and degradation of polyimide (PI) molecular chains. The destructive action of AO changed the surface chemical structure, which resulted in changes of the surface morphology and chemical composition of the samples. Friction and wear tests indicated that AO irradiation decreased the friction coefficient but increased the wear rate of both pure and Al _2O _3/SiO _2 filled PIs.