The Effect of Aging Reaction on the Colloidal Structures and Antiwear Property of Overbased Calcium Alkyl Salicylate

The aging process of overbased calcium alkyl salicylate is studied with FT IR, freeze etching electron microscopic observation (FE EM) and test of calcium distribution measurement. The results show that, when overbased calcium alkyl salicylate samples are subjected to aging reaction, the size of colloidal particles in samples decreases, the relative content of calcium hydroxide in colloidal particles increases, the viscosity of samples decreases and the total basicity number of samples increases. The detergency and anti wear properties of aged samples are better than that of non aged ones. Meanwhile, the aging efficacy of overbased calcium alkyl salicylate becomes worse if the water, methanol and residue of calcium hydroxide are removed from the reaction system. The primary aging mechanism is deduced according to the testing results as well.