Tribological and physical-chemical properties of aqueous solutions of cationic surfactants

Purpose - Modern cutting fluids often are real aqueous solutions of chemical compounds. That form of cutting fluid is simpler in preparation, as compared to emulsions and microemulsions. The water base is a good cooling medium of high-ecological value. The purpose of this paper is to discover water-soluble additives that could improve the lubricity of water. Design/methodology/approach - Three cationic surfactants were chosen to be analyzed. Their tribological properties were verified using two testers: T0-2 (four-ball machine) and T-11 (ball-on-disk). The results of the tests performed using friction couples made of steel (T0-2, T-11) and steel-ceramics (T-11) were satisfactory. Findings - The friction coefficients and wear scar diameters are even a few times smaller, as compared to the ones measured in a water environment. Originality/value - The paper demonstrates that the crucial role in improvement of the tribological properties is played by the surface activity of the additives (confirmed by the measurements of the surface tension and wetting angle). As the cationic surfactants are bactericidal and anti-corrosive, they can be classified as multi-purpose additives modifying water lubricity.