Nanofluids in Metal Cutting and Grinding: A Comprehensive Review

Nanofluids suspensions of nanoparticles in conventional cutting fluids—have emerged as promising alternatives to improve cooling, lubrication, and tribological performance in machining and grinding operations. This review synthesizes two decades of research (2003–2025) on nanofluid applications in metal cutting, with emphasis on their effects on tool wear, surface finish, cutting forces, and sustainability. Oxide-based nanofluids such as Al₂O₃ and ZnO consistently enhance thermal stability and cost-effectiveness, while carbon-based systems (CNTs, graphene) deliver superior tribological performance but face challenges of dispersion and high cost. Hybrid and eco-friendly formulations demonstrate synergistic benefits and support sustainable manufacturing, though scalability and long-term stability remain barriers. Advanced approaches, including cryogenic, field-assisted, and AI-integrated nanofluids, reveal breakthrough potential but are largely confined to laboratory studies. Reported improvements include up to 45% reduction in tool wear, 20–40% decrease in cutting forces, and 15–50% enhancement in surface finish. Persistent gaps include lack of standardized benchmarking, limited techno-economic validation, and health and safety concerns. This review concludes that industrial adoption of nanofluids will require development of scalable eco-friendly systems, comprehensive lifecycle assessments, and internationally accepted testing protocols.