Correlating topographical characteristics of relaxed layer to tribology in Cu-Gr-TiC composite system

Abstract

Abstract The copper graphite composites are often being applied as bearing materials in various industries. In present investigation, the correlation between the topographical characteristics of relaxed layer to tribology in Cu-Gr-TiC composite system has been investigated. For this purpose, the flake powder metallurgy approach was used to fabricate Cu-Gr-TiC composites and the tribology of these composites was studied under lubricating (synthetic SAE 20W40 motor oil) condition. Variable loads of 10 N–70 N, sliding velocities of 0.75 m s−1–3 m s−1, and sliding distances of 2000 m–8000 m were the test parameters for sliding wear of composites under lubricating conditions. The worn surfaces were examined using SEM and EDS while topographical parameters were studied by AFM. The other properties like mechanical and physical properties were also studied for the sintered samples to better correlate the overall results of surface topography and tribology. The tests depict the successful fabrication of the composites. The composite having 4.5 wt% TiC particles exhibit maximum hardness and least wear and CoF under lubricating environment. The results of sliding wear test conducted under lubrications revealed that rise in the concentration of nano TiC particles in the matrix improves the composite’s tribological performance. The mechanism of wear for pure copper sample is abrasion whereas for TiC particle reinforced composite is smooth ploughing and delamination. The surface topographical parameters that are average surface roughness, area peak to valley height and skewness depicted less roughness values and better load bearing capacity for 4.5 wt% TiC reinforced Cu-Gr sample. The fabricated TiC reinforced copper graphite composites could be utilized as bearing materials in automotive industries.