An experimental investigation on thermal conductivity and stability of aqueous and nonaqueous nanofluids containing Ag–Cu alloy nanoparticles

Advancement in technologies, particularly miniaturized technologies demand coolants having significantly enhanced thermal conductivity. The use of conventional heat transfer fluids in these applications can’t meet that requirement. Nanofluids, in which nanoparticles are dispersed in the conventional heat transfer fluids, have been developed and researched since the last decade in order to explore their promising cooling efficiency that enables development of smaller and smaller devices. Use of smaller particle sizes of highly conductive metals like Ag, Cu, etc in nanofluids can meet that requirement, but the stability of nanofluids particularly, when reactive metals like Cu in very small nano-scale sizes are used in base fluids like water is likely to be hampered. On the other hand, the use of noble metals like Ag in nanofluids are not recommended for their high cost. Keeping these factors in mind, in the present work Ag–Cu alloy nanopartices have been synthesized through wet chemical method at room temperature without using any inert gas protection and then the synthesized alloy nanoparticles are dispersed in water and ethylene glycol to produce nanofluids. The nanoparticles have been characterized by different structural and compositional characterization tools to confirm morphology, composition, elemental distribution within particles, crystal structure, average crystallite size and size distribution of particles. The measurements of thermal conductivity and stability of nanofluids have been carried out for different wt% loading of nanoparticles and have ensured the effectiveness of these nanofluids in targeted heat transfer applications.