Solid lubrication, graphite composites

Sliney, H.E. and Jacobson, T.P., Graphite-Fiber-Reinforced Polyimide Liners of Various Compositions in Plain Spherical Bearings, Proc. 2nd ASLE Inti. Conf. on Solid Lubrication, Denver, Colorado, (15-18 Aug. 1978) ASLE SP-6, p. 258. 

Four composites were studied. Each contained the same polyimide matrix resin, graphite fiber, and (NH4)2HP04. The composites differed in the type of solid lubricant additive employed and in the manner in which the fibers were woven. Two types of inorganic solid lubricant additives, denoted LI and L2, and two types of fiber weave, denoted W1 and W2, were employed. The materials to which... 

Graphite is one of the oldest and the most widely used (due to its lower price compared to M0S2 or BN) solid lubricants. It is obtained both as a soft mineral and as a man-made (synthetic) product. Graphite powders are used as solid lubricants in three ways (1) in dry films, (2) as an additive in liquids (oils) or semisolids (greases), and (3) as a component of self-lubricating (internally lubricated) composites. A NIOSH web site [8] has listed a total of 55 synonyms for graphite. 

Although self-reinforced UHMWPE was effectively abandoned for orthopedic bearings, interest has continued in other UHMWPE matrix composites, driven partly by new initiatives in nanocomposites materials science and polymer science. Indeed, UHMWPE matrix composites have been employed industrially for decades, and researchers have continued to explore the effect of historical standard fillers on the mechanical and dielectric properties of UHMWPE [36—40]. Solid lubricants, such as glass, graphite, ceramics (e.g., kaolin, AI2O3), and molybdenum... 

In general, the reduction of the liquid film thickness to fewer than 4-6 molecular layers can induce lateral ordering and lead to freezing. It has been demonstrated that water confined to nanospaces exhibits anomalous phase behaviors that are typically illustrated experimentally or via MD simula-tion. " Moreover, there is evidence that a possible liquid-solid phase transition occurs for ionic liquids in confined systems. We also reported the first simulation results of a liquid-solid freezing transition of an 1,3-dimethylimidazolium chloride ([Dmim][Cl]) ionic liquid between two parallel graphite walls. " This result is important to understand the microstructure and freezing processes of ILs in confined systems, such as lubrication, adhesion, and IL/nanomaterial composites. 

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