Abstract:Core-shell calcium borates/SiO2 composites were synthesized by a facile way, using borax, calcium nitrate and tetraethoxysilane (TEOS) as row materials. The structure and morphologies of calcium borate were investigated by TEM, XRD and FT-IR, finding that SiO2 shell was covered on the calcium borates. The oil acid (OA) modified composites were mixed into liquid paraffin and the tribological properties of the oleic acid modified calcium carbonates were evaluated on fourball tester at 392 N load, 1 450 r/min for 30 min. The results show that the composites possess excellent tribological properties. The wear scare diameter is decreased from 0.7 mm to 0.5 mm and the friction coefficient is dropped from 0.09 to 0.05 as 1.0% composites are added into base oil. The wonderful friction reducing and anti-wear properties of calcium borates/SiO2 composites are attributed to the formation of tribological film containing B, Fe and Si on the worn surface.
