The influence of polydiethylsiloxane (PDES) concentration on the tribolfilm of chlorophenyl silicone oil (CPSO) under high-temperature lubrication

As pivotal structural component, steels operating at high temperatures play a vital role in promoting the development of advanced equipment technology. Enduring and efficient lubricants are critical bottleneck for the construction of high-temperature frictional subsystems. Polydiethylsiloxane oil (PDES) significantly reduces the coefficient of friction (COF) (9.80–16.74 %) and wear rate (28.95–54.59 %) in the Si3N4–8Cr4Mo4V system without sulfur and phosphorus anti-wear additives at 250 °C. With only 1 wt% PDES, there is a remarkable 28.95 % wear rate reduction in the Si3N4–8Cr4Mo4V frictional system. The enhanced lubrication performance come from the Si–O tribofilm at lower PDES concentrations (1–15 wt%). Once exceeding a PDES concentration of 30 wt%, the as-formed Si–O tribofilm transitions to a Fe–Mo compound film, exhibiting superior friction reduction and wear resistance properties.