Microwave-Assisted Synthesis, Characterization and Tribological Properties of a g-C3N4/MoS2 Nanocomposite for Low Friction Coatings

Abstract

This study explores the tribological performance of microwave-assisted synthesized g-C3N4/MoS2 coatings. The two-dimensional transition metal dichalcogenide (TMD) nanosheet is getting prominence in the study of tribology due to its layered structure. The graphitic carbon nitride (g-C3N4) nanosheet was made using the calcination method and its nanocomposite with molybdenum disulfide (MoS2) was produced using a microwave-assisted method. The structure and morphology of the samples were characterized by some well-known methods, and tribological properties were studied by a pin-on-disc (POD) apparatus. Morphological analysis revealed that graphitic carbon nitride and molybdenum disulfide coexisted, and the layer structured MoS2 was well dispersed on graphitic carbon nitride nanosheets. BET analysis was used to determine the pore volume and specific surface area of the synthesized materials. The inclusion of MoS2 nanoparticles caused the composite’s pore volume and specific surface area to decrease. The reduction in g-C3N4 pore volume and specific surface area confirmed that the pores of calcinated graphitic carbon nitride were filled with MoS2 nanoparticles. The tribological property of g-C3N4/MoS2 nanocomposite was systematically investigated under different factors such as applied loads (5N to 15N), sliding speed (500 to 1000 mm/s) and material composition (uncoated, MoS2-coated, 9 wt.% of g-C3N4 and 20 wt.% of g-C3N4 in the composite). The optimal composite material ratio was taken 9%, by weight of g-C3N4 in the g-C3N4/MoS2 composite for a variety of levels of loads and sliding speeds. The results indicates that the incorporation of g-C3N4 in nanocomposites could reduce friction and improve wear life, which were better than the results with single MoS2. This study demonstrates a solution to broaden the possible uses of g-C3N4 and MoS2-based materials in the field of tribology.