Synthesis of high-temperature Calcium complex greases and comparingtheir thermal performance with Calcium grease

Grease is a semi-solid lubricant in which the structure is a gel composed of soap fibers arranged inlayers. Calcium greases are one of the most economical products but have low thermal stability athigh temperatures, for example, having an operating temperature of about ۹۰℃ and a dropping pointof ۱۴۸℃. We have developed a Calcium complex grease with adipic and sebacic acid as complexingagents in order to reach a higher thermal performance. The results show that the dropping points ofcomplex samples are above ۲۵۰℃, that is about ۱۰۰℃ higher than the simple one. The viscositytemperaturecures reveal that the viscosity of Calcium complex grease by sebacic acid reached fromapproximately ۱۲۰۰ mPa.s at ۸۰℃ to ۲۵۴ mPa.s at ۱۸۰℃ with the shear rate of ۵۰ sec-۱. This decreaseis more gradual compared to the sample with adipic acid. This can be explained by the longer carbonchain in sebacic acid, which helps keep the oil in the structure. Both complex greases obtainedacceptable amounts of viscosity at ۱۸۰℃ due to the considered shear rate and mineral base oil, whichare ۲۵۵ mPa.s and ۱۴۰ mPa.s for samples with sebacic and adipic acid, respectively.

کلیدواژه ها:

Gel ، Calcium grease ، Calcium complex grease ، Dropping point ، Viscosity ، highthermal stability