Nanofluids and their application in carbon fibre reinforced plastics: A review of properties, preparation, and usage

Renewed call for the replacement of conventional materials with carbon fibre reinforced plastics (CFRPs) in many high-performance applications is responsible for the current wave of research on minimum quantity lubrication (MQL) strategy in machining. Due to their competitive advantages over conventional materials, polymer matrix composites (PMCs) are now attracting the attention, of researchers, especially in the field of machining. Although most manufacturing methods require less machining, precision machining like milling and drilling call for more research inputs. For this purpose, this review article assesses various aspects of nanofluid preparation and its application in CFRPs. Recent scientific reports on nanofluids with a focus on properties, preparation, and application (including respective methodologies) were analyzed, to contribute to the growing database for future research in this field. This review article shows that cutting temperature and cutting force remain the key determinants of surface finish, while tool wear constitutes a major parameter that machining scientists would like to keep under full control by the use of appropriate cutting fluids. Uncertainties around the quality of nanofluids which is scarcely discussed in the literature is raised in this review, while advocating for more research to unravel it. Furthermore, this review article sheds more light on the machining operations of carbon fiber-reinforced plastics using nanoparticle-laden fluids for a safe and sustainable machining experience. Finally, this review assesses the possibility of achieving excellent CFRP processing using a sustainable approach to fill existing gaps identified in literature like wasted cutting liquids, environmental pollution, and exposure of operators to health hazards.