Study on the structure and friction properties of NCG/WS2 copper-based self-lubricating composites

In this study, Cu-matrix composites incorporating Ni-coated graphite and WS2 were synthesized using the discharge plasma sintering (SPS) method. X-ray diffraction analysis (XRD) and infrared Raman spectroscopy were employed for the physical phase analysis of the composites while scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) were utilized to examine and analyze the morphology and composition of the composite surfaces. The findings revealed that substituting graphite with an equivalent volume fraction of nickel-coated graphite significantly enhanced the hardness and compressive strength of the Cu-NCG composites by 10.4 % and 61.6 %, respectively. Additionally, the Cu-NCG-WS2 composite exhibits the lowest coefficient of friction (0.13), corresponding to the lowest wear rate (5.75x10(-5) mm(3)/Nm). This superior lubrication performance can be attributed to the fine debris present on the composite surface, which effectively fills in the cracks and pits, replenishes the broken lubrication film, and thereby restores a smooth surface, achieving effective lubrication.