Tribological Behavior and Mechanical Study of Different Tribo-pairs using Chlorophenylmethyl Silicone Oil Lubricant

With the increasing performance demands of high-end equipment, the operating temperature of core transmission components has reached up to 300 ℃, rendering conventional lubricating oils inadequate for long-term high-temperature lubrication. Chlorophenylmethyl silicone oil (CPSO), a modified silicone oil, demonstrates excellent viscosity-temperature properties, enabling effective lubrication at 300 ℃ over extended periods. This study selected four typical bearing steel materials (GCr15, M50, 40Cr15Mo2VN, CSS-42L), paired with M50 steel balls and Si₃N₄ ceramic balls, to construct two types of tribo-pair systems. The tribological behavior and mechanisms of tribo-pairs under CPSO lubrication were investigated using an SRV-4 high-temperature tribological tester. The results showed that the friction coefficient of steel-steel pairs fluctuated more (0.1~0.4) than that of ceramic-steel pairs. Although the wear rate of steel-steel pairs was lower, it increased with temperature, whereas the wear rate of hybrid ceramic pairs showed different trends as the temperature rose. Specifically, the wear rates of GCr15 and M50 steel decreased by 4.14% and 48.80%, respectively, at 300 ℃ compared to 250 ℃. XPS analysis of the wear scars revealed that this difference was attributed to the tribofilm formed on steel-steel pairs under CPSO lubrication, which consisted of Fe₂O₃. In contrast, the ceramic-steel pairs formed a low-shear FeCl₂ tribofilm on the wear interface, which had better wear resistance and effectively isolated direct contact between the tribo-pairs, thus reducing the system’s friction coefficient and wear.