Experimental investigations to enhance the tribological behaviour of biodegradable oil by using manganese doped ZnO/FMWCNTs nanomaterials as lubricant additive

Abstract

A novel binary hybrid nanomaterial of functionalized multi-walled carbon nanotubes (FMWCNTs) anchored on the surface of manganese doped zinc oxide nanosheets Mn0.10ZnO0.90 (MnZnO) were synthesized by using simple hydrothermal method. Further, the nanomaterials such as zinc oxide (ZnO), functionalized multiwalled carbon nanotubes (FMWCNTs) and ZnO/FMWCNTs hybrid nanomaterials have also been considered to evaluate the influence of doping of manganese in ZnO nanosheets on the tribological properties. The individual nanomaterials and synthesized hybrid nanomaterials were characterized by employing X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS), Thermo gravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS) techniques. The tribological performances of ZnO nanoparticles, FMWCNTs, ZnO/FMWCNTs and MnZnO/FMWCNTs hybrid nanomaterials dispersed in castor oil were investigated by a reciprocating ball on disk tribo tester. The castor oil with optimum concentration of 0.10 wt% MnZnO/FMWCNTs hybrid nanomaterials exhibited the superior tribological performance than the castor oil, ZnO, FMWCNTs and ZnO/FMWCNTs hybrid nanomaterial additives and reduced the coefficient of friction and wear volume by 26.21 % and 89.09 % respectively. The outstanding lubricating behaviour of MnZnO/FMWCNTs hybrid nanomaterial are corresponds to the synergistic mechanism of Mn doped ZnO nanosheets and FMWCNTs and formation of boundary film on the frictional surface. The surface characteristics and chemical composition of the worn bronze specimen lubricated with various nanomaterial additives have been examined using FESEM, EDS, optical profilometer and X-ray photoelectron spectroscopy.