The Antiwear Mechanism of Benzotriazole Derivative Containing S, P Active Elements

The load carrying capacity and antiwear property of S,P containing benzotriazole derivative (BM 3) were evaluated using a four ball test machine,and compared with those of zinc salt di(butyloctyldithiophosphate)(T 202 ) and amine salt of complex ester thiophosphate (T 307 ). The antiwear mechanism of BM 3 were studied by investigating the chemical states and the mass fraction of elements on the rubbed surfaces using X ray photoelectron spectroscopy (XPS) and electron probe microanalysis (EPMA) and the thermal decomposition products using gas chromatography mass spectrograph (GC MS).The results indicate that:BM 3 as additive in liquid paraffin possesses better load carrying capacity and antiwear property than T 202 and T 307 ;In the rubbing process,BM 3 reacts chemically with iron surface to form an excellent antiwear film,which is composed of carbon and oxygen elements at high concentrations and absorpted or complexed benzotriazole group and ferric phosphate,however the sulphur element is not detected in the antiwear film;The sulphur element in BM 3 molecular structure may transform mainly into the molecular structure of the thermal decomposition product (octyl mercaptan) which has comparatively weak absorpted capacity by way of the internal isomerization and the thermal decomposition of BM 3 under the thermal action in the rubbing process.Octyl mercaptan may exist in the base oil or continue to decompose to volatile low molecular mercaptan or H 2S.