Effects of fly ash introduction on friction and wear characteristics of brake pads

Abstract

Fly ash is a waste matter generally emitted abundantly from chimneys of the production facilities and should mostly be recycled. In this context, this study reveals the tribological effects of fly ash on brake pad components by doping the fly ash in basic brake pad matrix with various weight fractions of 30% (S30), 35% (S35) and 40% (S40) by reducing aluminum powder in the pad matrix. According to the results, as the fly ash concentration increases in the matrix, density and hardness of the structure were prone to decrease to an extent. Water immersion technique was used to determine density values and specially modified pin-on-disc tribotester was utilized to measure coefficient of friction (CF) and specific wear rate (SWR) values between brake pad samples and the cast iron rotating disc. Among prepared samples, maximum average reduction in density and hardness were observed to be by 3.97% and 10.67%, respectively. S30 depicted the minimum CF of 0.32 and maximum CF of 0.43 was performed by S40. Maximum specific wear rate was observed for S40 subtending to an increase of 8.67% from that of S30 to S40. Results showed that, though higher escalation in CF as the fly ash fraction elevates in the matrix, wear rates did not show a dramatic increase which is an indication of effectiveness of fly ash in brake pads in terms of braking performance and long term durability.