Sustainable lubrication: low molecular weight PTFE micro-particles as extreme pressure additives for heavy duty grease applications

• Published in: Industrial lubrication and tribology Vol. 73; no. 9; pp. 1209 - 1218
• Main Authors: Gupta, TCSM, Kumar, Ajay, Prasad, Babu
• Format: Journal Article
• Language: English
• Published: Bradford Emerald Publishing Limited 07.12.2021; Emerald Group Publishing Limited
• Subjects: Additives; Behavior; Biodegradability; Coefficient of friction; Composite materials; Cyclic loads; Electron beams; Friction; Friction reduction; High speed; Journal bearings; Lithium; Load; Load tests; Low molecular weights; Lubricants & lubrication; Mechanical properties; Molecular weight; Performance evaluation; Polytetrafluoroethylene; Scrap; Sintering; Solid lubricants; Titanium; Tribology; Wear resistance; Lithium complex greases; PTFE micro-particles; E-Beam process; Tribology
• ISSN: 0036-8792; 1758-5775
• DOI: 10.1108/ILT-12-2020-0478

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.