Influence of Surface Roughness on Wear Behaviour of Ceramic Nanocomposites

Abstract

The present work describes the influence of the surface roughness on the wear behaviour of Al2O3 and SiO2 based nanocomposites, prepared with the reinforcement of exfoliated graphite nanoplatelets (xGnP) and multiwalled carbon nanotubes (MWCNT). The surface roughness for the pure sintered samples along with the various composites, reinforced with the different loading levels of xGnP and MWCNTs is determined by the scratch resistance test, using the stylus probe method. The average surface roughness (Ra) was determined by the scratch profiling technique using a stylus profilometer, having a diamond tip indenter. A detailed morphological investigation of the polished surface of the composites was carried out using an optical microscope and SEM. A clear transition in the roughness average (Ra) was observed for the composites, when the applied load was varied in range of 1 to 3 mgf. Al2O3-xGnP and Al2O3-MWCNT nanocomposites having 0.2, 0.5, 0.8, 3 and 5 vol. % of the nanofillers and SiO2-xGnP and SiO2-MWCNT having 0.5, 1, 3 and 5 vol. % of the nanofillers were fabricated through the powder metallurgy route. SiO2 based composites were sintered at 1350oC for 4 h and for Al2O3 based composites, sintering was done at 1650oC for 3 h. The effect of surface roughness on the wear behaviour of the nanocomposites was determined on the basis of the worn surface topography and wear debris analysis.