Effect of multiple reinforcements (CNT/Si3N4) on hardness, electrical conductivity and friction coefficient of aluminium hybrid composites

Abstract

Present investigation reports on the development of aluminium hybrid composites using powder metallurgy technique. Two different reinforcements namely silicon nitride (Si3N4) and carbon nanotubes (CNT) were used to reinforce pure aluminium matrix. Ball milled powder morphology and microstructure of hybrid composites were studied using scanning electron microscope to study the dispersion of Si3N4 and CNT.Microstructure studies showed uniform dispersion of both the reinforcements in aluminium matrix. Microhardness was obtained by applying a load of 50 N for dwell period of 20 seconds. Electrical conductivity in terms of %IACS was obtained using Eddy current tester. Coefficient of friction was obtained by conducting scratch test by employing a load of 10 N for a stroke length of 10 mm and scratch velocity of 0.2 mm/sec. Microhardness was found to increase with increasing content CNT content while electrical conductivity was found to decrease. Finally coefficient of friction was found to decrease with increase in CNT content owing to its lubricating nature.