The effects of dust, copper particles, and iron particles on the high-temperature oxidative degradation behavior of aviation lubricating oil were systematically examined, and the high-temperature catalytic oxidation effects of single-particle and mixed-particle systems on the lubricating oil were further analyzed, respectively. Gas chromatography/mass spectrometry analysis results indicated that significant differences exist in the catalytic oxidation activity of particles toward lubricating oils, with the activity ranking in the descending order of copper particles > iron particles > dust. Notably, following oxidation by both metal and dust particles, the acid value, particle size, and viscosity of the oil sample exhibit a significant synergistic catalytic effect, even exceeding those of the oil sample oxidized by the same amount of metal particles. Specifically, relative to the pristine oil, the oil oxidized with 5 mg of copper particles and 5 mg of dust exhibits respective increases of 213.3%, 316.11%, and 661.43% in the aforementioned properties. This variation is attributed to the physical adsorption and chemical reactions between dust and antioxidants during oxidation, which deplete antioxidants and thereby exacerbate oil oxidation. Furthermore, this study further elucidates the potential synergistic oxidation mechanism induced by metal particles and dust particles.
Yang et al. (Sun,) studied this question.