Ionic Liquids as Performance Ingredients in Space Lubricants.

Area of Science:

• Materials Science
• Tribology
• Space Engineering

Background:

• Room-temperature ionic liquids offer low vapor pressure, ideal for space lubricants.
• Space environments pose challenges for lubricant supply, leading to boundary lubrication conditions.
• Effective boundary lubrication relies on forming protective adsorbed or reacted films.

Purpose of the Study:

• To evaluate hydrocarbon-mimicking ionic liquids (P-SiSO) as additives in multiply alkylated cyclopentane (MAC) for space applications.
• To assess the tribological performance of MAC with P-SiSO under vacuum and various atmospheric conditions.
• To determine the compatibility of MAC & P-SiSO with the space environment, including outgassing and electrical conductivity.

Main Methods:

• Tribological testing of MAC with P-SiSO under vacuum and different atmospheres (air, N2, CO2).
• Measurement of thermal vacuum outgassing and electrical conductivity.
• Comparison with heritage space lubricants: MAC and perfluoroalkyl polyethers (PFPE).

Main Results:

• Incorporating P-SiSO into MAC demonstrated beneficial lubricating performance.
• Effective lubrication was observed under vacuum and various atmospheric conditions.
• The MAC & P-SiSO blend showed compatibility with space environment conditions.

Conclusions:

• P-SiSO is a feasible multifunctional additive for hydrocarbon base oils in space exploration.
• The addition of P-SiSO enhances the lubricating properties of MAC for space applications.
• These findings support the use of P-SiSO-enhanced lubricants in demanding space environments.