An opportunity for partial replacement of phosphates and dithiophosphates in EP packages with boron-containing additives

The influence of a boric additive on standard four-ball machine lubricating parameters of tricresylphosphate, zinc-dithiophosphate and sulphurized esters of fatty acids is studied. The consumption of active elements from the bulk oil of some of the samples is estimated by atomic emission spectrometry before and after a one hour wear test. This analysis can provide valuable information for additive and surface film studies. A considerable amount of tricresylphosphate or zinc dithiophosphate can be replaced by the boric additive in synergetic mixtures, without sacrificing lubricating properties. This opens up an opportunity for the formulation of additive packages with improved ecological compatibility.