Effect of mechanical milling of fly ash on friction and wear response of brake friction composites

摘要

The effect of milled fly ash on the tribological response of brake friction composites is studied. Two specimens were developed using raw fly ash (RFA) and milled fly ash (MFA) and tested for the friction and wear performance at different loads (50-100 N) with sliding velocities varying from 1.7 to 3.3 m/s. It was observed that the spherically shaped RFA particles transformed into rough and uneven shaped particles after ball milling. The particle size range was found to be 22.05-206.19 mu m before milling which reduced to 3.02-40.64 mu m after milling while the specific surface area increased from 138.23 m(2)/m(3) to 1008.98 m(2)/m(3). The mu(avg) of RFA specimen varied from 0.23 to 0.57 during braking conditions. However, the MFA specimen experienced approximately a constant value of 0.52 at 50 N with the increase in sliding velocities, whereas slight variation was observed at higher loads. The results showed that the mechanical milling enhances the stability and consistency of friction coefficient as compared to raw fly ash.