An insight into smart self-lubricating composites

Abstract The concept of storing smart Cu-BTC m-MOF nanocontainers with oleylamine for lubrication before incorporating in the epoxy resin (ER) matrix system is still in practice to fabricate self-lubricating composites. It becomes the key approach while designing any ideal self-lubricating material. During application, these Cu-BTC m-MOF nanocontainers release stored liquid lubricant instantly to reduce the coefficient of friction (COF). The metal matrix composites having MoS2 are receiving attention these days in the field of materials research. Unlike the metallic self-lubricating composites, the composites having poor lubricating properties are not environmentally friendly due to the absence of the solid lubricants. The review aims to present recent research studies and developments in the field of smart metal matrix self-lubricating composites containing MoS2, which have applications in the aerospace industries. These materials are reinforced with either glass fibers or mineral fibers in a polymeric matrix along with solid particles such as lubricating MoS2. The review also outlines the impact of fiber length over tribological behaviors of RT/Duroid 5813 and PGM-HT through a case study, which is based on a numerical technique. In the last section, applications of ionic liquids are discussed to evaluate and quantify the friction in self-lubricating bearings. It was found that the ionic liquids (lubricants) behave like the Newtonian fluids in self-lubricating (porous) journal bearings in hydrodynamic domain even at higher rates of shearing. The future applications will be based on these smart self-lubricating nanocomposites and bearings and thus they became the source of inspiration to compile the review article.