Development and Characterization of Graphene Oxide Induced Alumina Composite Using Powder Metallurgy

Abstract

Graphene oxide (GO)-reinforced alumina (Al2O3) composites have garnered significant attention for aerospace applications due to their enhanced mechanical properties. This study investigates the synthesis, sintering behaviour, and mechanical characterization of GO-alumina composites fabricated using powder metallurgy. GO concentrations of 0.5, 0.9, and 1.2 wt.% were incorporated into an alumina matrix and processed via uniaxial cold pressing at 450 MPa, followed by liquid-phase sintering at 1500°C and 1550°C for dwell times of 60 and 90 minutes. Material characterization through X-ray diffraction (XRD) confirmed the presence of beta or gamma alumina, while Raman spectroscopy demonstrated the structural integrity of GO within the composite. Scanning electron microscopy (SEM) revealed a uniform dispersion of GO at lower concentrations but agglomeration at 1.2 wt.%, adversely affecting densification and mechanical performance. The relative density of the composites decreased with increasing GO content due to the formation of porous regions and weak interfacial bonding. The highest relative density (91.45%) was observed in pure alumina sintered at 1550°C for 90 minutes, while GO-reinforced samples exhibited reduced densification efficiency. Vickers microhardness testing indicated peak hardness at 0.5 wt.% GO, reaching 1838 HV at 1550°C for 90 minutes. However, higher GO content (>0.9 wt.%) led to a decline in hardness due to increased porosity and structural defects. The research finding indicate the potential of GO-alumina composites for aerospace applications but also underscores the limitations of conventional liquid-phase sintering in achieving optimal densification and mechanical properties. Compared to Spark Plasma Sintering (SPS), which provides rapid heating, improved grain refinement, and reduced porosity, the current processing method resulted in lower densification and increased defect formation. Future work should explore SPS to mitigate agglomeration, enhance densification efficiency, and improve the overall performance of GO-alumina composites.