Wear behavior of silica and alumina-based nanocomposites reinforced with multi walled carbon nanotubes and graphene nanoplatelets

Abstract

Spark plasma sintering (SPS) technique has been employed to fabricate silica (SiO2) and alumina (Al2O3) based nanocomposites having multiwalled carbon nanotubes (MWCNTs) and exfoliated graphite nanoplatelets (xGnPs) as reinforcement phase. The influence of MWCNTs and xGnPs on the wear behavior of the nanocomposites is analyzed. SiO2-MWCNT, SiO2-xGnP nanocomposites having 0.5, 3 and 5 vol% and Al2O3-MWCNT, Al2O3-xGnP nanocomposites having 0.2, 0.8, 3 and 5 vol% of the respective nanofiller were developed. SiO2-based nanocomposites were fabricated at 1350 °C under a pressure of 40 MPa whereas Al2O3-based nanocomposites were prepared at 1450 °C under a pressure of 50 MPa. Experimental results indicate that the wear behavior of various SiO2 and Al2O3-based nanocomposites improves with the introduction of carbonaceous nanofillers like MWCNTs and xGnPs. With the addition of these nanofillers, a continuous supply of graphitic reinforcement phase at the ceramic interface provided a better lubrication to the reinforced nanocomposites, which was not found in the case of monolithic SiO2 or Al2O3 samples. Both MWCNTs and xGnPs effectively withstand the applied stress during the wear test owing to their structural morphology once subjected to the wear strain. A remarkably varied wear behavior of both SiO2 and Al2O3 based nanocomposites was observed. SiO2 based nanocomposites depict narrower wear tracks with high wear rates whereas Al2O3 based nanocomposites were found to depict broader wear tracks with low wear rates.