Study of Tribological Properties of Nano-Sized Red Mud Particle-Reinforced Polyester Composites

Red mud (RM) in powder form is a waste substance obtained during extraction of pure alumina from Bauxite ore by Bayer's method. In this work, this red mud is used as reinforcement in nano-sized particulate form in the unsaturated polyester matrix. The mean particle size of 720 nm, 612 nm, 475 nm, 263 nm, and 110 nm were produced by ball milling for the milling period of 6-30 h. The composites were prepared by varying the size of the particle and for different particle weight fraction of 0.5, 1.0, 1.5, 2.0 and 2.5 wt.%. The wear characteristics of these red mud particulate composites were studied, and the effect of the particle size variation and particle weight fraction were reported. Particle size and particle content were observed to play a major part in frictional characteristics of the composites. The reduction in specific wear rate was 47.72% for 110 nm particle size composite sample with a weight fraction of 2.5 wt.%, and it showed 39.28% reduction in coefficient of friction on comparing with that of pure cured polyester resin. Red mud particles were characterized by FTIR, XRD and AFM analysis. Worn-out surfaces were analyzed by scanning electron microscope (SEM) for morphological study.