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Lubricants in electric and high-efficiency aircrafts Aviation electrification is likely to depend on several factors, including increased government focus on restricting carbon emissions, high awareness of electric aviation benefits, adoption attractiveness, cost compatibility, customer safety, certifications, and security features, among others. In addition, manufacturing infrastructure for batteries, e-motors, charging stations, generators, and other related electric aircraft technologies along with custom lubricant requirements for e-motors, generators, etc., is expected to play a critical role in the adoption of electric aircraft.
In the future, hybrid aircraft expect to play a crucial role in the aviation sector. These aircraft incorporate gas turbines for primary propulsion and electric batteries for secondary propulsion. In these systems, there would be paramount requirements for specialised lubricants, which could handle a variety of operational requirements. In addition, the advent of high-efficiency engines will require lubricants to perform thermal and load-carrying operations, which are expected to further boost the demand for innovative lubricants such as the enhanced ester class of lubricants.
Sustainability: A mandatory step for the future Driven by customer and investor demands and regulatory requirements, sustainability and supply chain changes are important factors being considered by lubricant manufacturers to develop innovative and sustainable products. Emphasis on obtaining raw materials through viable and renewable sources, energy-efficient and environment-friendly extraction methods, minimally toxic starting products, safe disposals, and minimum energy consumption during production are prime directives for developing sustainable lubricants for future aircraft.
Space: A challenging frontier for lubricants Necessity: Increased space operations, extreme working conditions, and efficient operability Lubricant requirement in the space entirely varies from conventional applications. In space operations, lubricants should be lightweight as more fuel can be carried. Safety of astronauts and equipment is paramount, which mandates optimum functioning of lubricants. Satellites, probes, and space vehicles function in extreme environments. They have several moving parts, which need to be properly lubricated
14 LUBE MAGAZINE NO.172 DECEMBER 2022
and maintained for optimum operations. According to the Aerospace Corporation, there are many mechanical systems operating in space, which have 1,000 rotations per minute and must last long for 15 years without lubrication change.
Space-grade lubricants: Choosing the right one Choosing a lubricant is utmost importance for space-related operations. Liquid lubricants such as oil and grease coagulate in extreme cold and become loose in hot conditions, requiring highly specialised space formulations. Solid lubricants are an excellent choice for extreme cold and contamination-sensitive equipment and operations. Lubricants such as polytetrafluoroethylene (PTFE), molybdenum disulfide, perfluoropolyether (PFPE), and lead coatings are perfect for space-related applications. However, solid lubricants are adversely affected by humidity, and have less lifespan than liquid lubricants. In addition, the radiation exposure can damage solid lubricants overtime and increase fragility of the lubricant.
Application areas Application areas of lubricants in satellites and spacecrafts include mechanical parts of the satellite, solar panel deployment systems, equipment, engine systems, hydraulic systems, ball-bearing systems, reaction wheels, mast cameras, actuators, contact bearings, drive gears, and other multiple mechanisms. Several space missions such as Mars Rovers, International Space Station, NanoSats, James Webb Space Telescope (JWST), among others use custom formulations of lubricants for optimum functioning. These mechanisms use lubricants, which are applied for life i.e. after the application is no scope to change them.
Extreme conditions such as fluctuating operating temperatures and varying loads can be solved through innovative formulations such as multiply alkylated cyclopentane (MAC) base oil, PTFE and PFPE-based formulations, polyimide-matrix products, molybdenum disulfide (MoS2)-based formulations, among others which work well under extreme conditions.
Ionic liquids: Better choice for space Ionic liquids have also emerged as the preferred liquid lubricant for space missions. These synthetic fluids consist of anions and cations. They have low vapor pressure with relatively low molecular weight. When used as lubricants, an ionic charge delivers coulombic interaction with surfaces to facilitate
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