Tribological and Microstructure Behavior of Quicklime (CaO) Filled Silicon Bronze Alloy for Bearing Material

Abstract

CaO filled silicon bronze (SiBr) alloy composites have been fabricated by a high temperature vacuum casting technique at five different weight percentages (0 wt%, 2.5 wt%, 5 wt%, 7.5 wt% and 10 wt% of CaO). The void contents, hardness and wear behavior of the CaO filled SiBr alloy composites were studied showing that the addition of particulates in base alloy reduces the void contents from 0.827 % to 0.504 % for 0 wt% to 7.5 wt% of CaO respectively. Similarly, the hardness of CaO filled SiBr alloy composites initially increases from 119.25 Hv to 140.8 Hv on addition of 7.5 % CaO but on further increase in filler content (10 wt%) the hardness decreases to 114.5 HV respectively. The specific wear rate of composite materials for applied load and sliding velocity factors showed surpassing behavior compared to unfilled alloy composites. To get the optimum response of wear behavior of composite materials the Taguchi L25 orthogonal array was applied and the result shows the higher S/N ratio i.e. 106.33 dB. The analysis of variance (ANOVA) result shows that the filler content plays a major effect compared to other factors. The particulate filled composites were examined through scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDAX) and atomic force microscopy (AFM) in order to understand the wear mechanism and morphology behavior of the composites.