The roles of nano-SiO2 particles on the tribological behavior of short carbon fiber reinforced PEEK

In the present work, the roles of low-loading (1 vol.%) nano-SiO2 particles (13 nm) on the tribological behavior of short carbon fiber (SCF)/PTFE/graphite (micro-sized) filled PEEK were investigated. Tribological tests were carried out at room temperature in extremely wide pressure and sliding velocity ranges, i.e. from 1 MPa to 7 MPa and from 1 m/s to 2 m/s, respectively. Under all conditions studied, the nanopartilces remarkably reduce the friction coefficients. With respect to the wear rates, however, the roles of the nanoparticles show a strong dependence on the sliding conditions. Under 1 MPa, the abrasiveness exerted by possible nano-SiO2 agglomerates seems to accelerate SCF destructions. Under pressures higher than 2 MPa, however, the nanoparticles remarkably reduce the wear rate. This effect is more pronounced under high pressures and especially at high sliding velocities. The protection of SCF/matrix interface by the nanoparticles is supposed to be the main reason for the enhancement of the wear resistance.