Investigation on frictional and machining characteristics of novel ALFA composite reinforced with treated waste fly ash

Abstract

Samples of aluminum-silicon alloy reinforced with fly ash (ALFA) composites were fabricated using liquid stir casting technique. The waste fly ash powders collected from power plant were modified by heat treating in a Linde type plasma reactor under neutral atmosphere. Three types of material samples such as Al-Si alloy, ALFA composite reinforced with untreated fly ash and ALFA composite reinforced with plasma treated fly ash were taken for the study. The wear behaviour in terms of weight loss (WL) and coefficient of friction (CoF) of thesamples under dry sliding conditions were tested by using a pin-on-disc friction and wear tester.Tests were performed at varied sliding velocities, normal loadings and sliding times.The wear surfaces of samples cleaned with acetone were analyzed by means of scanning electron microscopy (SEM).The experimental results revealed that the ALFA composite sample reinforced with treated fly ash has better tribological characteristics than that of other two material samples. ALFA composite sample reinforced with treated fly ash has higher wear resistance due to the in situ conversion of SiO2 to hard SiC particles in the vicinity of Al2O3 with favorable morphology of the particulates in the ternary mixture of Al2O3–SiC–C and presence of free carbon in the form of graphite in the Al-Si matrix.