The Enhancement of Overall Performance of Lubricating Grease by Adding Layered Double Hydroxides

Abstract

In this work, MgAl-layered double hydroxides (LDH) were synthesized by co-precipitation method using a colloid mill and characterized by XRD and SEM. It was found that the environmentally friendly LDHs had greater performance than the traditional antioxidant. By adding LDHs into large electric shovel grease (GRK-A) in open-pit coal mine, the service lifetime of grease was extended by 20%. With the increase in LDH addition, the grease sample attains greater activation energy, and the thermal oxidation and decomposition resistance become stronger. Comparing the energy storage modulus and flow transition index at different temperatures, adding the right amount of LDHs needs close attention for the system oxidation resistance and viscoelasticity. For the electric shovel grease, the best oxidation resistance and rheological properties can be achieved by adding 2% of LDHs. The rheological viscosity–temperature curves show that the grease samples with different ratios of solid LDHs have better low-temperature properties than the mine grease. This work outlines a simple method for creating an environmentally sustainable lubricant additive with the use of LDH. LDH serves as a novel inorganic antioxidant additive that is optimal for open gear lubrication and sliding friction.