Evaluation of Local Mechanical Properties in Depth in MoDTC/ZDDP and ZDDP Tribochemical Reacted Films Using Nanoindentation

摘要: Local mechanical properties in depth and near the surface of MoDTC/ZDDP ZDDP tribofilms, which exhibited obviously different friction coefficients a pin-on-disc test, were determined by using nanoindentation technique combined with in-situ atomic force microscopy (AFM) observation. Tapping-mode AFM observation revealed that film was much rougher than film. Nanoindentation measurement tribofilms possessed elasto-plasticities around several nanometers from surface, although both films showed same hardness modulus distributions except area. The indicated kinds tribofilm functionally graded materials; is, they consisted layer lower providing lubrication base higher serving to modify property differences at interface. Most importantly, surfaces shearing yield stress tribofilm. results this study suggest presence some solid lubricants such as MoS2 just below reduced boundary coefficient.