Facile Synthesis of Uniform Calcite Microcubes and Their Enhanced Tribological Performance in Lithium-Based Commercial Grease

Abstract

This study describes a facile synthesis of calcium carbonate (CaCO3) monodispersed fine particles from an abundant indigenous and economical source (quicklime) and its enhanced tribological performance as a green additive in commercial lithium grease (CLG). The effects of various experimental parameters on particle morphology were thoroughly examined, and the conditions were optimized. The synthesized uniform particles were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffractometry, and thermogravimetric (TG) /differential thermal analysis (DTA), and their results confirmed the calcite structure of the synthesized particles. The friction and wear studies were carried out under the applied load of 0.863 N at an ambient temperature for 5 min. The tribological performance of various amounts (1–7%) of cubic-CaCO3 (CCC) particles in CLG showed that 5 wt. % of CCC was the optimum concentration as additive in the present case. For comparison purposes, a commercial CaCO3 powder was used and a decrease in the friction coefficient of CLG was observed to be 33.4% and 16.4% for 5 wt. % CCC and commercial CaCO3 additives, respectively. The significantly enhanced antiwear and antifriction performance of the optimum CCC-CLG in comparison with the blank and commercial CaCO3-additized CLG was quite encouraging, and extensive studies in a real machine-operating environment are in progress for evaluation of the CCC-CLG blend to be used as an economical, green, and high-performance lubricant in mechanical components.