Purpose The purpose of this paper is to formulate heavy-duty lithium complex grease using low molecular weight poly tetra fluoro ethylene (PTFE) micro-particles as extreme pressure (EP) additive manufactured by E-beam scissoring and ultra-high speed grinding process of pre-sintered PTFE scrap. Design/methodology/approach Lithium complex grease is formulated with PTFE micro-particles, and optimum treat rate was studied by standard bench tests by ASTM D 2266 and IP-239 for tribological properties and compared with commercially available Molybdenum Di sulphide (Moly)-based lithium complex grease. The performance of the grease was further evaluated by a cyclic load test at varying speeds and loads to simulate the operational field conditions. Findings The lithium complex PTFE grease was manufactured using PTFE micro-particles as EP additive. The PTFE micro-particles dispersed in the lithium complex grease significantly improve the anti-wear performance and load bearing properties. Further, when the product was tested under a cyclic load conditions on standard tribological bench test against commercially available Moly lithium complex grease, shows stable anti-wear properties and reduced coefficient of friction. Originality/value The low molecular weight PTFE micro-particles, manufactured in the in-house electron beam (E-beam) and ultra-high speed micronizer facility from a pre-sintered PTFE scrap has been used as EP additive for grease applications for the first time. The results on the cyclic load tests indicate significant performance improvement in retaining the anti-wear and friction properties. Thus, value addition is done in formulating superior performance grease and evaluating under cyclic load conditions similar to field operating conditions and also in creating value added additives by converting the pre-sintered PTFE scarp which is environmental hazard due to poor biodegradability, creating a cyclic economy and a sustainable concept.

Lubrication is an important aspect when it comes to machinery and equipment in the industry where nanolubricants are extensively being explored as the future of lubricants. Nanolubricants are new-engineered fluids, which are dispersed with nanoparticles that aids in the interface movement by forming a protective layer hence reducing the wear and friction and dissipate the heat generated due to friction. In this research, a new synthetic lubricant is formulated by mixing two or more components of hydrogen bond donors and halide salt that achieves lower melting points compared to individual components. In this study, Glycerol and Polyethylene Glycol 600 (PEG) acts as the HBDs with common salt of Choline Chloride (ChCl). The nanolubricants were synthesised via two-step method by dispersing three different concentration of Functionalised Multi Walled Carbon Nanotubes (F-MWCNTs) of 0.01 wt%, 0.05 wt% and 0.10 wt% with the aid of ultrasonication. The stability of the suspensions were studied via optical microscopy and visual observation. The addition of F-MWCNT increased the resultant dynamic viscosity of the nanolubricant whereas the density was not much affected. Besides that, thermal conductivity showed positive enhancement for glycerol DES nanolubricant and negative enhancement for PEG DES nanolubricant. Thus, this study concludes that the thermophysical properties of DES base fluids and MWCNT have potential to be used as lubricants due to its enhanced physical properties.

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