Scratch Test of Epoxy Composites Reinforced by Alligned Carbon Nanotubes by Magnetic Field

Based on the observation obtained from the tested composites with and without the application of magnetic field, it can be concluded that both the measured friction coefficient and wear observed for the composites prepared under magnetic field are lower than that of an ordinary epoxy resin. As a consequence, it can be recommended that oriented MWCNTs reinforced epoxy composites can be successfully produced by application of permanent magnet. However, reduced friction coefficient in aligned composites can be explained in terms of the lubricating action offered by MWCNTs. During scratch, the large interfacial area offered by MWCNTs of relatively lower friction contributed in the significant friction decrease. Scratch in the normal direction, where the orientation of MWCNTs is perpendicular to the radial direction had higher friction due to the weak strength of MWCNTs in that direction. The enhanced wear resistance observed for aligned MWCNTs reinforcing epoxy may be attributed to the strengthening mechanism and the strong interfacial bonding offered by MWCNTs. Besides, as the magnetic intensity increased, wear significantly decreased. At relatively higher values of MWCNTs, wear recorded further decrease due to the better dispersion of MWCNTs offered by the magnetic field. Besides, MWCNTs can bind the epoxy chains together to decrease their slippage and improve the wear resistance. Alignment of MWCNTs increases the effective number of loaded MWCNTs in the load direction compared to that in aligned direction. As a consequence, the wear resistance of tested composites prepared at no magnetic field is low.