Development and Evaluation of a High Performance Universal Grease

Lithium based grease constitutes a large fraction of the grease consumed in the aviation and automobile industry. The durability and performance of the grease depends upon the additives added. The additive package used here includes PTFE (Poly Tetra-flouroethylene) for low coefficient of friction, ZDDP (Zinc Dialkyl Dithiophosphate) for anti wear properties, and Molybdenum sulfide for high load applications. We have developed a catalyst that helps PTFE to adhere to the metal surface at a low temperature. Block-on-cylinder tests and 4-ball weld tests were carried out to evaluate the effect of these variables. After carrying out matrix of tests at a low load and at high load, it is seen that the formulation with the combination of ZDDP, PTFE and the catalyst work in synergy. At low loads PTFE and catalyst provide wear protection and at higher loads thermal decomposition of ZDDP occurs which forms sulfates and phosphates, which adhere to metal surface to provide protection. Under extreme pressure conditions a synergistic interaction between PTFE, ZDDP, MoS₂ and catalyst is responsible for enhanced weld loads.