Effect of a new phosphate compound (BAFDP) addition on the lubricating performance of engine oils at elevated temperatures

- A new phosphate compound was synthesized and investigated as a potential antiwear lubricant additive in aircraft engine oil.
- The compound has high solubility in synthetic polyol esters.
- The tribological properties of the additive are superior to the normally used tricresyl phosphate (TCP).
- Tribochemical reactions were involved in the friction process and a surface protective film was generated on the lubricated metal surface.

A new phosphate compound bisphenol AF bis(diphenyl phosphate) (BAFDP) has been synthesized, characterized, and its tribological behaviours as a potential additives in aircraft engine oil were investigated at elevated temperature. BAFDP has high solubility in synthetic polyol esters and it is noteworthy that BAFDP exhibited effective friction reduction and antiwear characteristics when blended with trimethylolpropyl trioleate (TMPTO) and pentaerythritol oleate (PETO). The tribological properties of BAFDP were generally superior to the traditionally used tricresyl phosphate (TCP) in TMPTO and PETO. The antiwear mechanism is tentatively proposed on the basis of the morphology features and the chemical composition of the worn surfaces by SEM and XPS.