Tribological and mechanical characteristics of aluminum–graphene oxide composites synthesized by the ECAS method

Abstract In this study, aluminum–graphene oxide composite materials were fabricated via the powder metallurgy (PM) method. Graphene oxide (GO), synthesized using a modified Hummers method, was coated with a Ni–P layer through the electroless plating technique to establish a uniform and stable interface. Composite powders were prepared by mixing pure aluminum powders with Ni–P–coated GO powders in ethanol using an ultrasonic homogenizer. Pure aluminum and aluminum powders containing 0.5 wt.%, 1 wt.%, and 2 wt.% GO were sintered under pressure using current-assisted electrical sintering (ECAS) technique. Crystalline and microstructures of the composites were analyzed using XRD and FESEM, while Raman spectroscopy was used to evaluate structural defects in the GO sheets. Pure aluminum and GO-reinforced composites were evaluated for microhardness, tensile strength, and wear resistance. Highest hardness (60 HV) was found in the composite with 1 wt.% GO, which also showed the lowest friction coefficient and wear rate, along with highest yield and tensile strength. Mechanical enhancement arises from the combined effect of load transfer to graphene oxide and dispersion strengthening from its uniform distribution. GO addition also refines aluminum grain structure, boosting grain boundary strengthening. Consequently, 1 wt.% GO significantly improves the strength and wear resistance of aluminum composites.