Characterization and friction performances of Co–Al-layered double-metal hydroxides synthesized in the presence of dodecylsulfate

In this paper, Co–Al-layered double-metal hydroxides (CAD-LDHs) were synthesized by co-precipitation in the presence of dodecylsulfate (DDS) and characterized by XRD, FT-IR, TG–DSC, SEM. In addition, their frictional features were evaluated by four-ball friction tester, gear tester and air compressor. The results showed that synthesized CAD-LDHs have a hexagonal platelet morphology. Most crystallites have a disk diameter of around 150–250 nm and a thickness of about 20 nm, with a0 = b0 = 0.31 nm, c0 = 8.33 nm, d-spacing = 2.78 nm and gallery height = 2.30 nm. The specific surface area is 78 m2/g. DDS anions entered the interlayer of LDHs and were perpendicular to the LDH layer in a monolayer array. As a lubricant, CAD-LDH powder has excellent dispersability and suspension stability in the lubrication oil, and can significantly reduce friction coefficient (50.7%) and wear of friction pairs (17.9%). At the same time, they can reduce the temperature of lubrication oil (6.1%) and power consumption of driving motor (2.6–6.8%). Accordingly, CAD-LDHs may broadly be used as lubrication and anti-frictional materials.