Wear performance and mechanical properties of MWCNT/HDPE nanocomposites for gearing applications

MWCNT/HDPE nanocomposite spur gears prepared in concentrations of 0, 0.5, 1, 1.5, 2, and 2.5% by weight using centrifugal ball milling dispersion method followed by CNC milling. SEM examination revealed a sound dispersion of the MWCNT in the HDPE matrix until 2 wt.%. Nanocomposites exhibited higher decomposition temperature and thermal stability than neat HDPE. Yield strength increased linearly in nanocomposites up to 2 wt.%, and then it saturated. Nanofillers' addition steadily increased the young's modulus up to a weight fraction of 1.5 %, surging rapidly between 1.5 to 2 wt.%. In contrast, its rate of increase declined between 2 and 2.5 wt.%. The Taber abrasion test showed a reduction in wear loss of nanocomposites. The nanocomposites' toughness increased between 0 (neat HDPE) and 1.5 wt.% of MWCNT but declined at higher concentrations due to transition from ductile to brittle nature. At a torque of 5 N-m, the wear performance increased consistently with the increase in the concentration of nanofillers. At 10 N-m, 2.5 wt.% nanocomposite gears displayed a decline due to the increased brittleness. Satisfactory dispersion and developed interphase fervently contributed to the load transfer and mechanical properties. Nanofillers improved the wear resistance, hardness, and lowered plastic deformation. The gear damage mechanism changed from thermal bending to tooth cracking and deflection in the nanocomposite gears. The 2 wt.% MWCNT/HDPE nanocomposites emerged as potential gearing materials with enhanced hardness, tensile properties, uniform dispersion, thermal stability, wear performance, and reasonable toughness. (c) 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).