Focus on self‐repairing performance and mechanism of Cu‐DDP additive in base lubricating oil

PurposeThe purpose of this paper is to prove the self‐repairing Cu film of Cu‐DDP additive in base lubricating oil.Design/methodology/approachCu nanoparticles coated with dialkydithiophosphate (Coded as Cu‐DDP) were synthesized in situ by redox method. The size and structure of Cu‐DDP were characterized using transmission electronic microscopy (TEM) and electronic diffraction (ED) analysis. The self‐repairing performance of Cu‐DDP as additive in base lubricating oil was evaluated by MRH‐3 stock‐on‐ring testing machine. Scanning electronic microscopy (SEM), UMT‐2 tribometer, X‐ray photoelectron spectroscopy (XPS), and energy‐dispersive spectrum (EDS) were used to study the self‐repairing Cu film on the stock.FindingsThe test results showed that the modified Cu‐DDP additive in base lubricating oil exhibited excellent anti‐wear and friction‐reducing properties, as well as good self‐repairing performance.Research limitations/implicationsThe thickness of the self‐repairing Cu film was unknown, and the relationship between thickness of the Cu film and load, time, rotation velocity was still necessary to investigate.Practical implicationsThe Cu‐DDP additive was involved P and S elements, therefore, it is still promising to seek environment friendly additive without P and S elements.Originality/valueFor the first time, MRH‐3 stock‐on‐ring testing machine, Scanning electronic microscopy (SEM), UMT‐2 tribometer, X‐ray photoelectron spectroscopy (XPS), and energy‐dispersive spectrum (EDS) were widely used to study the self‐repairing Cu film on the stock.