The effect of thermal stressing on perfluoropolyalkylethers at elevated temperatures

摘要: Fultz et al. have reported that the thermo‐oxidative properties of linear PFPAEs can be improved by stressing fluid at elevated temperature (371°C) in presence air. A study M‐50 steel coupons exposed to unstressed and stressed PFPAE fluids 260 °C 330 each reveal complex surface layers. For coupon °C, a subsurface layer is observed between iron oxide substrate has been characterized as being composed FeF2. In contrast, marked increase thickness ∼2–3 times) when compared sample shows no evidence buried fluorine‐containing layer. An (330 °C) O–C test was required form FeF2 It proposed elimination fluorine found on increases upper limit from oxidation–corrosion studies. The implies acts like diffusion barrier which inhibits outward movement Fe0 decreased rate growth.