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Lubrication and Coating Challenges in Extreme Conditions
Published in Ahmed Abdelbary, Extreme Tribology, 2020
Space tribology is a subset of the lubrication-in-vacuum field, denoting the specialized discipline dealing with friction and wear phenomena related to satellites, spacecraft and space station components (Bhushan, 2000). Such components are designed to operate in space missions, where the environment is extreme. These extreme working conditions include very large temperature gradients, from very low temperatures, below −200ºC, up to +250ºC when exposed to the sun.
Metal Matrix Nanocomposites in Aircraft Engine and Space Applications
Published in Suneev Anil Bansal, Virat Khanna, Pallav Gupta, Metal Matrix Composites, 2023
Kumar Harshit, Pulkit Garg, Pallav Gupta
The extreme conditions in space present both a test and opportunity for material researchers. Around the Earth’s orbit, common aircraft experience various natural phenomena, for example, vacuum, ionizing radiation, atomic, and thermal radiation and plasma, alongside human-made debris. For instance, the International Space Station, during its 30–40-year life, will experience around 200,000 thermal cycles from +130°C to –130°C as it moves all through the Earth’s shadow. Re-emergence vehicles for Earth and Mars missions may experience temperatures that surpass around 2000°C. Basic shuttle missions, along these lines, required lightweight space structures with high accuracy and dimensional stability within the sight of dynamic and thermal unsettling influences. Composite materials, with their high explicit solidness and low coefficient of thermal expansion (CTE), give the vital qualities to create lightweight and dimensionally stable structures. The accomplishment of space missions relies fundamentally upon the unwavering quality of space systems, and this is subject to the life and usefulness of their segment parts (Roberts, 2012). Space tribology is the administration of friction and wear forms in those parts that have a tribological component, and spotlights on hostile to grinding and against wear properties (Fan et al., 2015; Jones & Jansen, 2008; Voevodin & Zabinski, 2005). Notwithstanding, propelled aircraft engines require propelled materials to meet their efficiency, eco-friendliness, and motor properties alongside upthrust to weight proportion of the aircraft. There are three significant materials-related drivers answerable for the improvement of aerospace engines. To start with, materials and production cost decrease to diminish maintenance and support costs. Also, bringing down the weight of the material to improve explicit fuel utilization of the motor and decrease the general load of the aircraft. Thirdly, improving the nature of materials to permit structuring developments to improve the engine cycle giving higher effectiveness and motor execution; model: higher generally speaking weight proportions and higher temperatures in the blower and turbine organize separately. Materials impact all aspects of the aircraft, beginning with the purchase, design structure, fuel utilization, operational execution, safety, maintenance, dependability, recycle, removal, and so on. Aviation materials are characterized as basic materials that convey the load applied on the airframe during flight tasks (counting navigating, take-off, cruising, and landing) (Shanian & Savadogo, 2006). Basic materials are used to guarantee the security of aircraft at basic territories, for example, the wings, fuselage, empennage, landing gears, tail base, rotor cutting edges, the airframes, thermal insulators etc. Reports concerning tribological brakes that execute the slowing down activities, gripping tasks, or over-burden assurance of shuttle or space instruments are restricted, particularly in specific fields like friction materials. Along these lines, both organic matrix and metal matrix composites (MMCs) have been created for space applications.
Response Mechanism of Structure and Tribological Properties of WS2/P201 Hybrid Lubrication System Under Atomic Oxygen Irradiation
Published in Tribology Transactions, 2023
Jian Liu, Zhen Yan, Xiao Zhang, Junying Hao, Haibin Zhou, Weimin Liu
A lubrication malfunction in a space system can inflict serious damage on an aerospace mission (8). Therefore, the demand for novel lubricating materials with outstanding tribological properties in the aerospace machines is ever increasing to meet the new frontier of space mechanisms (9–11). Both solid and liquid lubrication, as the traditional technologies used in space, have specific disadvantages (12–14). The solid lubricant is easy to wear out and generates debris, and its lifetime is limited. The liquid lubricant is highly volatile and creeps easily, resulting in contamination. A combination of solid and liquid lubricating materials can minimize their individual shortcomings and maximize the respective advantages through synergistic lubrication effects, which have attracted extensive attention recently and have become a further trend in the space tribology field (15, 16).
Influence of lubricants on the performance of journal bearings – a review
Published in Tribology - Materials, Surfaces & Interfaces, 2020
Sunil Kumar, Vijay Kumar, Anoop Kumar Singh
Later on, Fleischauer and Hilton [129] discussed the space tribology applications which included sliding motion, combined sliding and rolling motion of mechanisms in heavy load and high-speed conditions. Fusaro and Khonsari [130] presented the review for space lubricants, lubrication mechanisms, environmental effects, additives and bearing failures. The tribological behaviour of PFPE lubricants (Krytox, Demnum and Fomblin-Z) in steel/steel surface interface under vacuum environment has been analysed [131]. Low wear resistance was observed in vacuum environment compared to air environment. High wear resistance was observed for krytox lubricant in air for different load conditions. High wear resistance was observed for both Demnum and krytox lubricants in vacuum for high load conditions. The Fomblin-Z lubricant observed low wear resistance and low CoF.