Accelerated Thermo-Catalytic Degradation of Perfluoropolyether (PFPE) Lubricants for Space Applications

Perfluoropolyethers (PFPE) are a class of frequently used lubricants in space applications due to their high stability under demanding conditions. However, they susceptible aging, with the aging mechanism being dependent on specific material combination and storage condition. A Lewis-acid-induced thermo-catalytic degradation is concern, for example, steel-on-steel sliding contact, can be relevant long-term (LTS). Accelerated experiments were performed Fomblin® Z25 Krytox™ 143AC investigate thermal influence iron(III) fluoride (FeF3) at elevated temperatures (180 °C, 200 220 °C) up total duration 2000 h. The effects monitored via selected analysis techniques: mass loss samples subsequent evaporation during FTIR spectroscopy changes chemical structure, dynamic viscosity measurements investigation potential impact molecular mass, ball-on-disc tribological test setup obtain friction behavior aged lubricants. Distinct differences between two types PFPE regarding found. was highly affected by presence FeF3 within conditions, exhibiting loss, significant drop viscosity, an increased coefficient reactions.