Influence of rare earth oxide and graphite on the mechanical and tribological properties of Fe/Cu based sintered friction materials

Fe/Cu-based sintered friction materials are proven potential materials for heavy-duty applications. The current research explores the influence of rare earth oxide (Nd2O3) and graphite on the tribological characteristics of Fe/Cu-based friction materials. The constituents present in the friction material are Fe, Cu, Cg (1%, 3%, 5%, 7%), BaSO4, and Nd2O3 (5%). Optical microscopy and elemental mapping studies reveal the homogeneous distribution of elements in the matrix. Sintered density of the specimens showed a maximum of 70% of the theoretical density measured by Archimedes' principle. XRD analysis shows no new phase formation in all the sintered specimens. A peak microhardness result of 96 HV is obtained in specimen NG-01. The pin-on-disc tribotests are performed at an axial load of 50 N at a sliding velocity of 5.5 m/s. Specimen NG-03 with 3% graphite exhibited an optimum wear rate with a friction coefficient of 0.45. The surface morphology and elemental composition of the worn specimens are investigated. The morphological features inferred that the wear mechanism is predominantly mixed abrasive and adhesive.