Tribological properties of calcium carbonate powders modified with Tween 40 as lubricant additives

Abstract

In this experiment, nanometer calcium carbonate was prepared by metathesis method. The nanometer calcium carbonate was modified by non-ionic surfactant-tween 40. The nanometer calcium carbonate before and after modification was analyzed and characterized by various methods. Scanning electron microscope (SEM) result show the size of the unmodified nano-calcium carbonate is about 200-400nm, while the particle size of the modified particles is about 200 nanometers. Contact angle indicate that CаCO₃ powders become hydrophobic after modified. Moreover the friction and wear properties of Tween 40-CаCO₃ as lubricant additives in rapeseed oil were evaluated with a four-ball friction and wear tester. Tween 40-CаCO₃ could improve the anti-wear and friction reducing capacities of rapeseed oil can conclude from the friction results. X-ray photoelectron spectroscope of worn steel surfaces indicated that an absorption film containing rapeseed oil and 40-CаCO₃ was formed.