Abstract: Heterocyclic compounds are now received an increasing attention in the mechanical lubrication research area. However, the tribological properties of nitrogen-containing heterocyclic compounds without sulphur and phosphorus in multi-means of contact are still rarely discused. A new zero-sulphur/phosphorus quinazolinone amine as lubricating oil additive is prepared, the frictional behaviors of which in liquid paraffin are evaluated by four-ball tester, block-on-ring tester and all-purpose friction and wear tester. The rubbed surfaces are investigated using optical microscope, scanning electron microscope and X-ray photoelectron spectroscopy. The tribological test results indicate that the soluble additive in liquid paraffin has good tribological performances, which can remarkably improve the friction and wear conditions and evidently enhance the load-carrying capacity of the base oil. It is supposed that the additive adsorbs and reacts with the steel surfaces during the rubbing process and generates a surface protective film composed of ferrous oxide, organic containing-nitrogen compounds and nitrogen-containing metallic chelate, which is effective on improving the antiwear, friction-reduction and load-carrying capacity of liquid paraffin.

Key words: Additive, Anti-wear, Friction-reduction, Point/line/surface contact, Quinazolinone amine, Tribological properties