ABSTRACT
Zn-dialkyldithiophosphates (Zn-DADTP-s) are widely used in automotive lubrication being still among the most popular components of motor oil additive packages. They are also employed in plastic greases, hydraulic oils, metal working lubricants, etc. The main functional properties of the additive compositions investigated included lubricating properties as estimated in standard four ball machine tests; thermal stability, determined by thermogravimetric analysis, thermal oxidation stability, estimated in a laboratory gasometric apparatus. Zn-DADTP ensures high Initial Seizure Loads and even below 2 % concentration achieves the results for the seizure loads of the reference package but Weld Loads with this additive are the lowest and the Load Wear Indices are rather modest. Zn-DADTP-s are considered to be additives of a relatively low thermal stability, which is a disadvantage for the mechanism of their antiwear action, and their overall performance in motor oils, since the latter have to fulfill their duties in zones of high temperatures as well.
